Care and Service of Passenger and Light Truck (LT) Tires€¦ · Chapter 1 - Basic Tire Information...

© Rubber Manufacturers Association, August 2011

Care and Service of Passengerand Light Truck (LT) Tires

Including Tire Replacement Guidelines andRecreational Vehicle Applications

Chapter 1 - Basic Tire InformationOverview ....................................................................................................................Chapter 1, page 2Tire Construction and Terminology ..........................................................................Chapter 1, page 2Tire Size Designations ..............................................................................................Chapter 1, page 3The Sidewall Story ....................................................................................................Chapter 1, page 6Tire Service Description ..........................................................................................Chapter 1, page 10Uniform Tire Quality Grading Standards for Passenger Car Tires ........................Chapter 1, page 11Sidewall Marking for Retread Tires ........................................................................Chapter 1, page 11

Chapter 2 - Tire Care and ServiceOverview ..................................................................................................................Chapter 2, page 13Proper Tire Inflation ................................................................................................Chapter 2, page 13Tire Loading ............................................................................................................Chapter 2, page 16Sudden Ride Disturbance or Vibration ..................................................................Chapter 2, page 16Tire Inspection Guidelines ......................................................................................Chapter 2, page 16Tire Service Life ......................................................................................................Chapter 2, page 18Tire Rotation ............................................................................................................Chapter 2, page 20Conditions Affecting Tread Wear ............................................................................Chapter 2, page 22Proper Tire Repair ....................................................................................................Chapter 2, page 24Passenger and Light Truck Used Tires ..................................................................Chapter 2, page 26Spare Tire Maintenance ..........................................................................................Chapter 2, page 26Tire Storage Recommendations ............................................................................Chapter 2, page 26Cleaning Tires ..........................................................................................................Chapter 2, page 27Tire Sidewall Indentations ......................................................................................Chapter 2, page 27Tire Explosions and Flammable Substances ........................................................Chapter 2, page 28Tire Spinning ............................................................................................................Chapter 2, page 29Mounting and Demounting Procedures ................................................................Chapter 2, page 29Tire/Wheel Balancing and Installation ..................................................................Chapter 2, page 32“Zipper Ruptures” in Steel Cord Radial Medium and Light Truck Tires ..............Chapter 2, page 34Tire Retreading ........................................................................................................Chapter 2, page 35

Care and Service of Passenger and Light Truck (LT) Tires Including Tire Replacement Guidelines and Recreational Vehicle Applications

Table of Contents

Chapter 3 - Tire Replacement GuidelinesOverview...................................................................................................................Chapter 3, page 37 The Right Tire for the Vehicle..................................................................................Chapter 3, page 37Tire Size, Inflation & Load.......................................................................................Chapter 3, page 37Self-Supporting Runflat Tire Replacement .............................................................Chapter 3, page 40Tire Mixing................................................................................................................Chapter 3, page 41Replacing Less Than Four Tires ..............................................................................Chapter 3, page 42 Tire Rim/Wheel Selection........................................................................................Chapter 3, page 42Tire, Vehicle Clearance and Tire Diameter .............................................................Chapter 3, page 43Plus Sizing ................................................................................................................Chapter 3, page 43Important Considerations ........................................................................................Chapter 3, page 45 Passenger and Light Truck Used Tires ....................................................................Chapter 3, page 46

Chapter 4 - Recreational Vehicle ApplicationsOverview ..................................................................................................................Chapter 4, page 48RV Tire and Vehicle Placards/Labels ......................................................................Chapter 4, page 48RV Tire and Vehicle Load Limits ..............................................................................Chapter 4, page 49Proper RV Tire Inflation ............................................................................................Chapter 4, page 50Proper RV Tire and Vehicle Loading ........................................................................Chapter 4, page 52How to Determine an RV’s Actual Weight ..............................................................Chapter 4, page 53RV Tire Inspection Guidelines ..................................................................................Chapter 4, page 54Severe Service Operation ........................................................................................Chapter 4, page 54Sudden Ride Disturbance/Vibration........................................................................Chapter 4, page 58Tire Rotation ............................................................................................................Chapter 4, page 58RV Tire Service Life ..................................................................................................Chapter 4, page 58Proper Tire Repair ....................................................................................................Chapter 4, page 59Parking an RV ..........................................................................................................Chapter 4, page 60Passenger and Light Truck Used Tires ....................................................................Chapter 4, page 61Storing RV Tires ........................................................................................................Chapter 4, page 61

Purpose

The purpose of this manual is to provide both thetire service professional and end user (consumer)with an understanding of the many factors that areessential to the proper care and service ofpassenger and light truck tires (also known as"light vehicle tires"*).

This manual is not all inclusive. RMA does notintend for it to eliminate the need for in-depth,hands-on training, especially in such areas as: tiremounting and demounting; tire and wheelbalancing; tire retreading; tire pressure monitoringsystems (TPMS) and tire repairing.

Personnel that service tires must receiveprofessional training. Tire manufacturers andindustry organizations, such as the Tire IndustryAssociation**, provide comprehensive, hands-ontraining programs for tire service professionals.

The "WARNINGS" and "CAUTIONS" contained inRMA publications are important and must befollowed. Questions pertaining to specific productsor pieces of service equipment should be addresseddirectly to the manufacturer of that product.

RMA does not endorse, certify, approve, consent, orconfirm in any way products, brands,creations/inventions, etc. of any company,corporation, business or firm.

Introduction

The Rubber Manufacturers Association (RMA)represents companies that manufacture tires in theUnited States. The RMA and its members recognizehow important tires are to safety.

Tires are designed and manufactured withadvanced technology and great care to providethousands of miles of excellent service. Formaximum safety, performance and service life, theymust be maintained properly.

This Care and Service Manual will address theseand other factors relative to the care and service ofpassenger car and light truck tires. For the mostcurrent printed materials, visit the RMA web site at

www.rma.org and click on “Publications” to searchfor other manuals, bulletins, wall charts, etc. Forquestions regarding RMA publications, call (202)682-4800.

Care and Service of Passengerand Light Truck (LT) TiresIncluding Tire ReplacementGuidelines and Recreational

Vehicle Applications

CHAPTERS:

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Published by

Rubber Manufacturers Association1400 K Street, NW Suite 900

Washington, DC 20005www.rma.org

All rights reserved. The contents of this publication may notbe reprinted or otherwise reproduced in any form without

the express written permission of RMA.

© Rubber Manufacturers Association, August 2011

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* The Federal Motor Vehicle Safety Standards Part 139 (FMVSS-139) defines “light vehicles” as motor vehicles with a gross vehicle weight rating (GVWR) of 10,000lbs. or less. Tire sizes for light vehicles include all passenger car tires and light truck tires through load range “E.”** The Tire Industry Association (TIA) is a trade association that represents all segments of the tire industry, including those that manufacture, repair, recycle, sell,service or use new or retreaded tires, and also those suppliers or individuals who furnish equipment, material or services to the industry. Visit www.tireindustry.orgfor more information.

Basic Tire Information

Chapter 1, Page 1

CHAPTER 1 (OF A 4 CHAPTER SERIES)

BASIC TIREINFORMATION

CSPLT1-0811

Overview

Tires are designed and manufactured to meet strictgovernmental requirements, internal companystandards, vehicle performance characteristics andconsumer expectations. Modern tire technologyblends a unique mix of chemistry, physics andengineering to give consumers a high degree of tireperformance that provides safety, reliability,efficiency, long wear and comfort. Tires aremanufactured, inspected and tested to assureconsumer safety and satisfaction. As a result,properly cared-for tires will provide a longer servicelife.

Tire Construction andTerminology

Nearly all passenger and light truck tires are radial plyconstruction that provides sidewall flexibility withbody cords that run across the tire nearlyperpendicular to the beads. Radial tires have belt plieswith steel and/or other cords laid diagonally underthe tread to stabilize and reinforce the tread areaduring contact with the road.

Passenger Tire vs. Light Truck Tire Construction -Differences between passenger and light truck tireconstruction are due to their different uses andoperating conditions. Compared to passenger tires,light truck tires usually operate at higher inflationpressures and carry greater loads on a regular basis.Light truck tires are typically designed for moresevere service such as in commercial vehicleapplications or for off-road use. In order to meet theseperformance needs, light truck tires may haveadditional components/layers and heavier-dutymaterials. As a result, light truck tires tend to beheavier than passenger tires.

Rubber Compounding - Rubber compounding is acomplex science of mixing different raw materialstogether to produce rubber compounds withspecific characteristics. Rubber compounds differdue to their location and functional purpose in thetire. Example: Outside tread compound providestraction and treadwear characteristics. Althoughrubber is the main material used for making tires, there are a number of other materials used as well.

These materials are combined with specific rubbercompounds in the different components that makeup the tire's construction.

Body Ply - Most tires have one or two body plies,each typically comprised of polyester, rayon, ornylon cords within a rubber layer. Body pliesfunction as the structure of the tire and provide thestrength to contain the inflation pressure.

Bead - Tire bead bundles (usually strands of wire)secure the tire to the wheel.

Belts - Typically, two belts with steel cords laid atopposing angles. Belts provide stability to the treadarea of the tire, which contributes to wear, handlingand traction.

Innerliner - A rubber compound used to retain theinflation pressure inside the tire.

Sidewall - A rubber compound used to cover thebody plies on the sides of the tire, which providesabrasion, scuff and weathering resistance.

Tread - The tread rubber compound and treadpattern provide grip and abrasion resistancecontributing to traction and treadwear.

Chapter 1, Page 2


Tire CutawayTypical Construction Features

1st Belt 2nd Belt

Section Height - The height of a new tire from thenominal rim diameter to the top of the tread.

Section Width - The width of a new tire includingnormal sidewalls, but not including protective sideribs, bars, or other decorations.

Overall Diameter - Twice the section height(unloaded) plus the nominal rim diameter.

Rim Width - The measurement on the inside of therim between the two flanges.

Rim Diameter Code - The nominal rim diameter ininches.

Tire Size Designations

Size designation systems presently in use:

P-MetricEuropean Metric (a.k.a. Metric)*LT-MetricLT High FlotationLT NumericEuropean Commercial Metric (C-Type)*ST-Type Special TrailerT-Type Temporary Spare

Size designations usually include letters, as well asnumbers, which have the following meanings:

P = P-Metric (Passenger)LT = Light TruckC = European Commercial (Light Duty)ST = Special TrailerT = Temporary SpareR = Radial ConstructionF = Self-Supporting, RunflatD = Diagonal (Bias) Construction B = Belted Bias Construction

Other letters denoting speed symbols such as “M”,“N,” “P,” “Q,” “R,” “S,” “T,” “U,” “H,” “V,” “W,” “Y”, “(Y),”“Z,” etc., may appear in the tire size designation orservice description. (See “Tire Service Description” onp. 10 for more information.)


Chapter 1, Page 3

Cross-Section of Tire and Rim

* European Metric tires do not have an alpha character prefix in the size designation.

Passenger Tire Examples:

P-Metric

Chapter 1, Page 4

P265/70R16P 265 70 R 16

P-metric Nominal Cross-section Width(millimeters)

Ratio of Height toCross-section Width

(aspect ratio)

Radial Construction Rim Diameter Code

P225/50R15 90HP 225 50 R 15 90H


Ratio of Height toCross-section

Width (aspect ratio)

RadialConstruction

Rim DiameterCode

Load Index &Speed Symbol

(ServiceDescription)

P205/60ZR15P 205 60 Z R 15




Speed Symbol RadialConstruction

Rim DiameterCode

European Metric (a.k.a. Metric)

T115/70*15T 115 70 *D or R 15

Temporary Spare Nominal Cross-sectionWidth

(millimeters)


(aspect ratio)

D (Diagonal/Bias) or R(Radial) Construction

Rim Diameter Code

225/45R17 91H225 45 R 17 91H

Nominal Cross-sectionWidth (millimeters)


(aspect ratio)

Radial Construction Rim Diameter Code Load Index & SpeedSymbol

(Service Description)

T-Type Temporary Spare

NOTE: Tire size designations without service descriptions are no longer in general use.



Chapter 1, Page 5

LT265/75R16 Load Range ELT 265 75 R 16 E

Light Truck Nominal Cross-section Width(millimeters)



RadialConstruction

Rim DiameterCode

Load Range

31X10.50R15LT Load Range C31 10.50 R 15 LT C

Overall Diameter (inches)

Nominal Cross-section Width

(inches)

Radial Construction

Rim Diameter Code

Light Truck

7.50-16LT Load Range D7.50 - 16 LT D

Nominal Cross-section Width (inches)

Non-radial Construction(bias)

Rim Diameter Code

Light Truck

ST225/75R15 Load Range DST 225 75 R 15 D

Special Trailer Nominal Cross-section Width(millimeters)



Radial Construction

Rim Diameter Code

LT235/85R16 120/116Q Load Range ELT 235 85 R 16 120/116Q E

Light Truck Nominal Cross-section Width(millimeters)

Ratio of Heightto Cross-

section Width(aspect ratio)

RadialConstruction

Rim DiameterCode

Load Index &Speed Symbol

(ServiceDescription)

(Single/Dual)

Load Range

NOTE: Tire size designations without service descriptions are no longer in general use.

* It is common for P-Metric and European Metric tire sizes to be placed on pickups, vans, sport utility vehicles, and other vehicles thatmight be perceived as a “light truck.” Check to see which type of tire is on the vehicle. For more information, see Chapter 3, “TireReplacement Guidelines.”

** Tires designed specifically for trailer use in highway service.

ST-Type Special Trailer **

LT Numeric

Flotation

LT-Metric

Light Truck Tire Examples*:

225/70R15C 112/110R 225 70 R 15 C 112/110R

Nominal Cross-section Width(millimeters)

Ratio of Height to Cross-section


Radial Construction

Rim Diameter Code

EuropeanCommercial (Light Duty)

European Commercial Metric (C-Type)

LoadRange

LoadRange

Load Index & SpeedSymbol

(Service Description)(Single/Dual)

Load Range

The Sidewall Story

Tires have very useful information molded onto theirsidewall. It shows the brand and model name of thetire, its size, whether it is tubeless or tube type, themaximum load and the maximum inflation, safetywarning(s), and much more. Figures 1 and 2 (on p. 8and 9) show typical information on the sidewall ofpassenger car and light truck tires.

P225/60R16 97T - Size marking and ServiceDescription (load index, speed symbol) for a P-Metricspeed-rated passenger tire. An aspect ratio number,typically ranging from 30 to 80, in a tire sizedesignation indicates the ratio of the tire sectionheight to section width. Aspect ratios are also referredto as “series” and “profile” numbers. In the examplebelow of a tire with an aspect ratio of 60, the sectionheight of the tire is 60% of the section width.

SERVICE DESCRIPTION - Includes the load index(numeric) and speed symbol (alpha character). In theexample above, “97” is the load index; “T” is thespeed symbol. The numeric load index is a codegenerally ranging from 50-129 that represents themaximum load carrying capacity. Alpha speedsymbols represent the speed capability (see page 10for more information).

RADIAL - A tire with a radial construction mustshow the word “RADIAL” on the sidewall. A radialtire is also delineated by the character “R” in the sizedesignation.

MAX. LOAD 730 kg (1609 lbs) AND 240 kPa (35 psi)MAX. PRESSURE COLD - Indicates maximum loadand maximum cold inflation pressure of the tire.Sidewall markings are given in both metric andEnglish units. Follow tire inflation pressurerecommendations on the vehicle tire placard,certification label, or in the owner’s manual.

PLIES/FABRIC INFORMATION - The ply/fabricinformation identifies the number of plies and typeof cord materials in the tire tread and sidewall areas.

DOT MA L9 ABCD 0309 - The “DOT” symbol certifiesthe tire manufacturer's compliance with U.S.Department of Transportation (U.S. DOT) tire safetyperformance standards. Next to these letters is the tireidentification number (TIN) - also known as the tire“serial” number. The first two digits are the factorycode indicating where the tire was made. The lastfour digits are numbers identifying the week and yearof manufacture (Example: "0309" means third week ofthe year 2009).

Chapter 1, Page 6

NOTEThe recommended inflation pressure on a vehicletire placard is based on a number of factors (suchas load). Therefore, it may not be the same as themaximum inflation pressure molded on the tire'ssidewall. For example, the U.S. Department ofTransportation allows the following maximuminflation pressures in passenger tires:

Standard Load tires - 240 kPa (35 psi),300 kPa (44 psi), or 350 kPa (51 psi) - butno increase in the tire's load (from that ofthe 240 kPa pressure) is allowed. Extra Load tires - 280 kPa (41 psi) or 340kPa (50 psi) - but no increase in the tire'sload (from that of the 280 kPa pressure) isallowed.

In other words, the pressure indicated on the tiresidewall is the MAXIMUM allowed in the tire,irrespective of the vehicle or the load. It is not tobe used exclusively for setting pressure for anyspecific vehicle.


Other characters in between the first four and lastfour are optional manufacturer's codes for tire type,make, etc. All tires produced after September 2009must have the full TIN on the intended outboard sideof the tire and at least a partial TIN on the othersidewall. The partial TIN does not include the datecode.

Prior to the year 2000, the last three digits of the TINrepresent the date code. (Example “025” is thesecond week of 1995.) For the 1990-1999 decadesome tires may be marked with a symbol (such as atriangle) after the TIN date code. Beginning in theyear 2000, the last four characters are numbersidentifying the week and year (example “0309”means the third week of the year 2009).

TUBELESS - The tire must be marked either"tubeless" or "tube type."

M + S - This mark is commonly found on “allseason” tires. In several formats, the letters "M" and"S" indicate the tire is intended for limited mud andsnow service.1 Other formats include: "MS," "M/S,"or "M&S."

MOUNTAIN-SNOWFLAKE SYMBOL - Thismark is commonly found on dedicated winter/snowtires. Tires that meet the RMA definition forpassenger and light truck tires for use in severesnow conditions are marked on at least one sidewallwith the letters "M" and "S" (as stated above) plus apictograph of a mountain with a snowflake, asshown here.2

TREADWEAR 600 TRACTION ATEMPERATURE B - Treadwear, traction, andtemperature are quality grades established andrequired by U.S. DOT under the Uniform Tire QualityGrading Standards (UTQG). These standards areonly applicable to passenger car tires with someexclusions. See page 11 for a more detailedexplanation on UTQG.

TThhee ffoolllloowwiinngg ppeerrttaaiinnss ttoo tthhee LLiigghhtt TTrruucckk SSiiddeewwaallllEExxaammppllee sshhoowwnn iinn FFiigguurree 22.. Other markings on alight truck tire sidewall have the same meanings asthose defined for passenger car tires.

LT245/75R16 Load Range E - This markingindicates that the size designation is for a metriclight truck tire with a Load Range “E.” The loadrange identifies the tire's load and inflation limits.

SERVICE DESCRIPTION - Includes the load index(numeric) and speed symbol (alpha character). Inthe light truck sidewall illustration, “120/116” arethe load indices for single/dual application; “Q” isthe speed symbol. The numeric load index is a codegenerally ranging from 50-129 that represents themaximum load carrying capacity. In the light truckexample, single and dual application load indicesare listed. Alpha speed symbols represent the speedcapability. See page 10 for more information.

MAX LOAD SINGLE 1380 kg (3042 lbs) AT 550 kPa(80 psi) MAX PRESSURE COLD indicates themaximum load of the tire and correspondingmaximum cold inflation pressure for that load whenused as a single. Sidewall markings are given inboth metric and English units. Follow tire inflationpressure recommendations on the vehicle tireplacard, certification label, or in the owner’smanual.

MAX LOAD DUAL 1260 kg (2778 lbs) AT 550 kPa(80 psi) MAX PRESSURE COLD indicates themaximum load of the tire and correspondingmaximum cold inflation pressure for that load whenused in a dual configuration. Sidewall markings aregiven in both metric and English units. Follow tireinflation pressure recommendations on the vehicletire placard, certification label, or in the owner’smanual.


Chapter 1, Page 7

1 Refer to RMA Tire Information Service Bulletin, Vol. 10, “RMA Snow Tire Definitions for Passenger and Light Truck (LT) Tires.”2 Refer to RMA Tire Information Service Bulletin, Vol. 37, “RMA Definition for Passenger and Light Truck Tires for Use in

Severe Snow Conditions.”


Chapter I, Page 8

FIGURE 1: Passenger Tire Example

P225 / 60R 16 97T M+S

P225/60R1697T

DO

TM

AL9

ABCD

0309M

AX.LOAD

730

kg(1

609

lbs)

AN

D24

0kP

a(3

5p

si)M

AX

.PR

ES

SU

RE

CO

LD

P-metric passenger tire

Nominal width of the tirein millimeters

Aspect Ratio (ratio of height to width) Radial Construction

Rim Diameter Code

Load Index and Speed Symbol

Maximum load carryingcapacity and maximum cold inflation pressure

UTQG ratings

PLIES: SIDEW

ALL

PO

LYE

STE

R2

RADIAL TUBELESSTR

EADP

OLY

ESTE

R2

+S

TEE

L2

TIRE NAME

BRANDNAME

Tire ply compositionand material used

TRE

AD

WE

AR

600TR

AC

TION

ATEM

PERATURE

B

DOT Tire IdentificationNumber

Tubeless


Chapter 1, Page 9

FIGURE 2: Light Truck Tire Example

LT245 / 75R 16 120/116 Q M+S

DO

TM

AL9

AB

CD

0309

MAX. LO

AD

SIN

GLE

1380kg

(3042)AN

D550

kPa

(80psi)M

AX.PRESS.COLDMAX.LOADDUAL1260KG(2778lbs)AT550kPa(80psi)

MAX

PRESS.

CO

LD

LOAD RANGE ERADIAL TUBELESS

Light truck tire

Nominal width of the tirein millimeters

Aspect Ratio (ratio of height to width)

Radial Construction Rim Diameter Code

Load Range

Load Index (single/dual) and Speed Symbol

Maximum load carrying capacity at maximum cold inflation pressure(single and dual load)

TIRE NAM

EP

LIES

: SID

EW

ALL

PO

LYE

STE

R2

TR

EA

DP

OLY

ES

TER

2+

STEEL

2+

NYLO

N1

DOT Tire IdentificationNumber

Tire ply compositionand material used

BRANDNAME

Tubeless

Tire Service Description

Load Index - The load index is a numerical codeassociated with the maximum load a tire can carry atthe speed indicated by its speed symbol underspecified service conditions up to 130 mph (210km/h). For speeds in excess of 130 mph (210 km/h),the actual load on the tire shall be reduced inaccordance with tire selection. For detailedinformation, refer to the appropriate standardsmanual (such as The Tire and Rim AssociationYearbook) for the vehicle load adjustment (based onspeed) for "V," "W," "Y," and "ZR" rated tires.

Tires with the same load index, regardless of the tiresize, may carry the same load, but not always, andthey may require different inflation pressures. Inaddition, some tire sizes are available in more thanone load index. Refer to Table 1 for different examples.The load index may not be used independently todetermine replacement tire acceptibility for loadcapacity. An equal or greater load index does notalways correspond to equal or greater capacity at allinflation pressure settings, particularly whencomparing P-metric and European metric passengercar tires.

Speed Symbol - The speed symbol in a tire servicedescription is also known as a “speed rating.” SeeTable 2. The speed symbol indicates the speed categoryat which the tire can carry a load corresponding to itsload index under specified service conditions. Speedratings are based on laboratory tests that relate to performance on the road, but are not applicable if tiresare underinflated, overloaded, worn out, damaged, oraltered.

Although a tire may be speed rated, RMA does notendorse the operation of any vehicle in an unsafe orunlawful manner. Furthermore, tire speed ratings do

not imply that a vehicle can be safely driven at themaximum speed for which the tire is rated, particularly under adverse road and weather conditions or if thevehicle has unusual characteristics. Consult the tiremanufacturer for speed capability when there is noservice description or speed symbol marked on the tire.


Chapter 1, Page 10

M M 81 130Q Q 99 160R R 106 170S S 112 180T T 118 190U U 124 200H H 130 210V V 149 240W W 168 270Y Y 186 300(Y) -- >186 >300

ZR

**

Speed Category*

MPH KM/H

Speed Symbol

SpeedRating

* In standardized laboratory tests that relate to highway speeds.Actual tire speed and performance capability depend on factors suchas inflation pressure, load, tire condition, wear, and drivingconditions.

** Any tire having a maximum speed capability above 149 mph(240 km/h) may, at the tire manufacturer's discretion, include a"Z" in the size designation (i.e. P275/40ZR17). For tires having amaximum speed capability above 186 mph (300 km/h), a "Z" mustappear in the size designation and must include a servicedescription with a “(Y).”

Consult the tire manufacturer for speed capability when there is noservice description or speed symbol marked on the tire.

Examples:P275/40ZR17 max speed > 149 mph - consult tire mfr.P275/40R17 93W max speed = 168 mphP275/40ZR17 93W max speed = 168 mphP275/40ZR17 93Y max speed = 186 mphP275/40ZR17 (93Y) max speed > 186 mph - consult tire mfr.

TABLE 2: Speed Symbols

TTAABBLLEE 11:: EExxaammpplleess ooff TTiirree SSiizzee aanndd LLooaadd IInnddeexx VVaalluuee DDiiffffeerreenncceessLoad Capacity (lbs.) at Various Inflation Pressures

Size Load Index

26 psi(180 kPa)

29 psi(200 kPa)

32 psi(220 kPa)

35 psi(240 kPa)

38 psi(260 kPa)

41 psi(280 kPa)

44 psi(300 kPa)

P205/65R15 92 (SL) 1213 1279 1334 1400 1400 1400 1400P205/60R16 92 (SL) 1069 1157 1257 1389 1389 1389 1389

205/55R16 90 (SL) 1014 1102 1190 1279 1323 1323 1323205/55R16 91 (SL) 1047 1135 1224 1312 1356 1356 1356205/55R16 94 (XL) 1003 1102 1179 1268 1356 1433 1477

Uniform Tire Quality GradingStandards for Passenger Car Tires

The National Highway Traffic Safety Administration(NHTSA) established the Uniform Tire QualityGrading Standards (UTQG)3 as a way to assist theconsumer to compare various tires. UTQG applies tothe vast majority of passenger car tires (excludingtires such as winter-type snow tires).

NHTSA sets the standards that rate the relativeperformance of tires based on three criteria:treadwear, traction and temperature. The grades aremolded on the tire sidewall. Replacement tires havea label affixed to the tread that lists and explainsthese grades. A vehicle's engine type, transmissiontype, gear ratios, driving styles, road surface,inflation pressure, etc. can affect actual performanceof the tire from one vehicle to another.

The UTQG tire characteristics are as follows:

Treadwear - The treadwear grade is a comparativerating based on the wear rate of the tire when testedunder controlled conditions on a specifiedgovernment test course. In the example shown, thetreadwear grade is 600, which means it would weartwice as well on the government course as a tiregraded 300. The relative performance of tiresdepends upon the actual conditions of their use andmay depart significantly from the norm due tovariations in driving habits, service practices anddifferences in road characteristics and climate.

Traction - The traction grades, from highest tolowest, are AA, A, B, and C and they represent thetire's ability to stop on wet pavement as measuredunder controlled conditions on specifiedgovernment test surfaces of asphalt and concrete.The traction grade assigned is based on braking

(straight ahead) traction tests and does not includecornering (turning) traction.

Temperature - The temperature grades are A (thehighest), B and C, representing the tire's resistanceto the generation of heat and its ability to dissipateheat when tested under controlled conditions on aspecified indoor laboratory test wheel. Thetemperature grade is established for a tire that isproperly inflated and not overloaded. Excessivespeed, underinflation, or overloading, eitherseparately or in combination, can cause heatbuildup which may result in tire damage and/or tirefailure.

UTQG Tire Marking Example

Sidewall Marking for Retread Tires

Applicable retread tires, which operate on publicroads in the United States, are permanently markedon the sidewall with "DOT-R" and followed by a 7 to13 character tire identification number (TIN). If theoriginal new tire was certified by the manufacturerto the applicable safety standards and regulations,the original "DOT" certification mark and the newtire TIN may remain on the tire casing afterretreading, along with the retreader's TIN.

If a speed rated tire is retreaded, the speed rating isno longer valid.

3 Refer to Code of Federal Regulations: 49 CFR 575.104.4 Refer to Code of Federal Regulations: 49 CFR 571.139.

Chapter 1, Page 11

NOTEDon’t sell, use or retread tires whose originalDOT marking/serial number has been removed,obliterated or branded over.

NOTEIn addition to the UTQG standards, all passengercar tires must conform to federal performancesafety requirements.4


Tire Care and Service

Chapter 2, Page 12

CSPLT2-0811

CHAPTER 2(OF A 4 CHAPTER SERIES)

TIRE CARE AND SERVICE

Overview

Tires are designed and manufactured with advancedtechnology and great care to provide thousands ofmiles of excellent service. For maximum safety,performance and service life, they must be maintainedproperly.

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This chapter will address these and other factorsrelative to the care and service of passenger car andlight truck tires.

Proper Tire Inflation

The recommended inflation pressures for tires aretypically measured in pounds per square inch (psi)and are indicated on the vehicle tire placard,certification label or in the owner's manual. Neverset tire inflation pressures below the recommendedinflation pressure found on the vehicle tire placard,certification label or owner's manual. Underinflation causes excessive heat build-up and internalstructural damage that may lead to a tire failure,even at a later date. Do not exceed the maximuminflation pressure shown on tire sidewall. Overinflated tires (over the maximum molded on the tiresidewall) are more likely to be cut, punctured ordamaged by sudden impact from hitting an obstacle,such as a pothole.

PPrrooppeerr IInnffllaattiioonn iiss CCrriittiiccaall - Inflation pressure enablesa tire to support the load and to control the vehicle,therefore proper inflation is critical. With the rightamount of inflation pressure, the vehicle and the tireswill achieve their optimum performance. In addition totire safety, this means your tires will wear longer andimprove vehicle fuel consumption.

Chapter 2, Page 13

NOTEThe pressure indicated on the tire sidewall is themaximum allowed in the tire, irrespective of thevehicle. Follow the vehicle manufacturer’srecommendations for inflation pressure foundon the vehicle tire placard, certification label orin the owner’s manual.


Driving on tires with improper inflation pressureis dangerous.

• Under inflation causes excessive heat build-up and internal structural damage.

• Over inflation makes it more likely for tires tobe cut, punctured or broken by suddenimpact.

These situations can cause a tire failure,including tread/belt separation, even at a laterdate, which could lead to an accident and seriouspersonal injury or death.

Consult the vehicle tire placard, certification labelor the owner's manual for the recommendedinflation pressures.

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Note that some vehicles may have different coldinflation pressures for tires on the front and rearaxles.

It is impossible to determine whether radial tires areproperly inflated just by looking at them (see Figure3). You must use a tire gauge to properly check theinflation pressure. Motorists should have their owngauge and keep it in the vehicle.

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Properly Inflated 50% Under Inflated

Check inflation pressure with an accurate tire gauge.A gauge calibrated in 1 psi increments up to 60 psiis sufficient for most passenger tires. A dual headgauge calibrated in 2 psi increments up to 100 psi issufficient for light truck tires. Even if it is difficult tocheck the inflation pressures of inside tires in dualfitments, it is imperative that these inflationpressures be checked and properly maintainedbecause the inside dual tires are subjected to moresevere operating conditions, such as:

• High heat exposure, due to close proximity tobrakes

• Lower air circulation to assist in cooling • Crowned road surfaces (which can cause inside

dual tires to support more of the load than theoutside dual tires)

WWhheenn ttoo CChheecckk IInnffllaattiioonn PPrreessssuurree - Check inflationpressure when tires are cold, that is, when the vehiclehas been parked for at least 3 hours or has been drivenless than one mile at moderate speed. The inflationpressure in all tires, including the spare tire and insideduals, should be checked with an accurate tire gaugeat least once per month. Additional checks should bemade before long trips, carrying heavy loads, towing

a trailer and any time high speeds are anticipated.This includes vehicles equipped with a Tire PressureMonitoring System (TPMS). Maintaining properinflation pressure maximizes fuel economy andoptimizes overall tire performance.

Never “bleed” or reduce inflation pressure whentires are hot from driving, as it is normal forpressures to increase above recommended coldpressures. If a hot tire pressure reading is at orbelow recommended cold inflation pressure it maybe dangerously under inflated. In this case,immediately determine the cause and/or have thetire checked by a tire service professional.

Passenger and light truck tires may lose 1 to 2 psiinflation pressure per month under normalconditions and 1 to 2 psi for every 10 degrees Ftemperature drop. If a tire continually loses morethan 2 psi per month, have it checked by a tireservice professional.

Significant changes in altitude or temperature atwhich a vehicle will regularly operate will result inchanges in inflation pressure and will require aninflation pressure check and adjustment.

CCoonnttiinnuuoouuss IInnffllaattiioonn PPrreessssuurree LLoossss - Any tire thatcontinually requires re-inflation is a serious safetyrisk. The cause may be the result of a puncture, roadhazard damage, leaking valve, tire mountingdamage, or other irregular condition. Continuoususe of a tire in an under inflated condition will resultin heat build-up and internal tire damage. This mayresult in a tire failure, including tread/beltseparation. Tires that continuously require re-inflation should be inspected thoroughly by a tireservice professional and be properly serviced orreplaced immediately.


Inflating an unsecured tire is dangerous. If itbursts, it could be hurled into the air withexplosive force resulting in serious personal injuryor death.

Never inflate a tire unless it is secured to a vehicle,tire mounting machine or other restraining device.

Chapter 2, Page 14

DDuuaall TTiirree AAsssseemmbbiilleess -- For vehicles equipped withdual tire assemblies (duals), if one of the dual tiresbecomes significantly underinflated or flat, the othertire will carry the load for both tires, resulting in anoverloaded condition. Both tires should be inspectedby a tire service professional for damage.

TTiirree PPrreessssuurree MMoonniittoorriinngg SSyysstteemmss ((TTPPMMSS)) -- It is stillimportant to check inflation pressure at least once amonth, even on vehicles that are equipped with aTPMS. TPMS are designed to be beneficial andaccurate. However, they should not be solely reliedon for inflation pressure maintenance since somesystems may have limitations, such as:

• Lack of warning of low inflation pressure untilone or more tires are as much as 25% below thevehicle manufacturer recommendations.

• May only detect inflation pressure differencesbetween tires (in other words, if all tires are losinginflation pressure at the same rate, it is possible thatthe TPMS will not adequately warn of inflationpressure loss).

• May not warn of rapid inflation pressure loss in asingle tire.

Under inflation (prior to a TPMS warning) isincreasingly dangerous at high speeds, heavyvehicle loads, extended distances and at highambient temperatures.

SSppaarree TTiirree IInnffllaattiioonn PPrreessssuurree - Full-size andtemporary spare tire inflation pressure should bechecked monthly and before any long trips. Use anaccurate gauge. T-type temporary spare tires require60 psi (420 kPa). When adjusting inflation pressurein T-type tires, do so in small amounts since the tireis smaller and the pressure level changes rapidly. Donot over inflate.

VVaallvvee CCaappss - Always cover the valve stem with asealing cap. This helps prevent moisture, dirt andother contaminants from entering the valve core, aswell as providing an additional seal.

IInnffllaattiioonn PPrreessssuurree ffoorr OOffff--RRooaadd UUssee - Inflationpressures for tires used in most off-road situationsshould be the same as those for highway driving. If a

lower inflation pressure is used to gain additionalflotation/traction at low speeds, the tires must be re-inflated before resuming driving on the highway or athigher speeds, whether on- or off- road.

UUssiinngg NNiittrrooggeenn IInnffllaattiioonn -- Nitrogen may be offeredas an alternative to air for tire inflation. Nitrogen isan inert (non-flammable) gas - basically, nothingmore than dry air with oxygen removed (air containsabout 78% nitrogen). Because of its inert properties,nitrogen is often used in highly specialized serviceapplications and/or demanding environments. Forinstance, aircraft, mining and commercial/heavyapplications use nitrogen to help reduce the risk ofinternal combustion (fire) if the brake/rim/wheelcomponents overheat. Also, dry nitrogen is used inprofessional racing to help reduce variation ininflation pressures (caused by moisture) where evensmall differences in pressure can affect vehiclehandling at the extreme limits of performance.

For normal tire service applications, nitrogeninflation is not necessary. However, nitrogeninflation is permissible as its properties maycontribute to minor reductions in inflation pressureloss. Nevertheless, several other sources of pressureleaks, such as punctures, tire/rim interface (bead),valve, valve/rim interface, and the wheel, maynegate the benefit of nitrogen. If the tire inflationpressure is below the pressure specified on thevehicle tire placard, certification label or owner’smanual, the tire must be re-inflated -- whether withair or nitrogen -- to the proper inflation pressure. Donot operate tires under inflated and/or over loaded.

Depending on nitrogen alone to reduce therequirements for inflation maintenance may lead tounder inflated operation which may result inpremature tire failure. With the right amount ofinflation pressure, the vehicle and tires will achieve

Chapter 2, Page 15

NOTEWhether inflated with air or nitrogen, regularinflation pressure maintenance remains criticaland necessary. Use of nitrogen alone is not areplacement for regular inflation pressuremaintenance.


ire Maintenance Manual

Chapter 2, Page 16

their optimum performance. In addition to tiresafety, this means your tires will wear longer andimprove vehicle fuel consumption.

Nitrogen and air can be mixed in any and allproportions. Nitrogen filled tires can and shouldhave air added whenever nitrogen is not readilyavailable, to maintain proper inflation as specifiedby the vehicle manufacturer.

For information on storing and handling nitrogen,follow the manufacturer's and/or supplier's safetyguidelines.

Tire Loading

To avoid over loading tires, maintain the properinflation pressure and never exceed the vehicle'sload capacity, gross axle weight ratings (GAWR) orthe Gross Vehicle Weight Rating (GVWR) stated onthe vehicle tire placard, certification label or thevehicle owner’s manual. The vehicle load must alsobe distributed so that no individual axle, tire or dualassembly is over loaded.

The maximum load for each tire is molded on thetire sidewall (along with the maximum inflationpressure for that load). Never exceed the maximumlimits on the tire, rim or wheel assembly.

For improved fuel efficiency, reduce vehicle weightas much as possible by removing unnecessary itemsfrom your cargo storage areas (in addition tokeeping tires properly inflated).

Consult your vehicle owner’s manual for loadrecommendations and special instructions (such astrailer towing).

Sudden Ride Disturbance orVibration

If the vehicle experiences a sudden vibration or ridedisturbance and/or there is a possibility the tiresand/or vehicle have been damaged, graduallyreduce speed. Do not abruptly brake or turn. Drivewith caution until you can safely pull off the road.Stop and inspect the tire. If the tire is under inflated

or damaged, deflate and replace it with the sparetire. If a cause cannot be detected, the vehicleshould be towed to the nearest vehicle or tire dealerfor an inspection.

Tire Inspection Guidelines

In addition to maintaining inflation, regularlyinspect the tire tread and sidewalls for irregulartread wear, cracking, scrapes, bulges, cuts, snags,foreign objects or other damage resulting from use.It is recommended that tires, including the spare, beperiodically inspected by a tire service professionalduring routine maintenance intervals such as oilchanges and tire rotations.

Remove any stones, glass, foreign objects, etc.embedded in the tread to prevent damage. Evenminor damage can lead to further injury andeventual tire failure. Also, it is a good practice tocheck between dual tire/wheel assemblies forforeign objects, like large rocks, that may havebecome lodged between the tires, especially afteroff-road service.

Tires with excessive cracking on the tread orsidewall(s) should be removed from service. This istypically caused by under inflation, over loading,


Under inflation and/or over loading of a tirecauses excessive heat build-up and internalstructural damage. This may cause a tire failure,including tread/belt separation, even at a laterdate, which can lead to an accident and seriouspersonal injury or death.

Over loading a vehicle can have other serioussafety consequences such as suspension orwheel failure, increased braking distance orbrake failure (particularly on steep grades), andadverse vehicle handling/stability.

Consult the vehicle tire placard, certification labeland owner’s manual for the recommendedvehicle load limits and tire inflation pressures.

improper storage, and/or improper long-termparking.

Replace tires when worn to 2/32” (1.6 mm) depthremaining anywhere on the tread face. For vehicleswith a GVWR in excess of 10,000 pounds (4,536 kg),federal regulations state that tires on the front axleshould be removed when worn to 4/32” (3.2 mm)tread depth.5

Built-in tread wear indicators or “wear bars,” whichlook like narrow strips of smooth rubber across thetread, will appear on the tire when the tread is wornto 2/32” (1.6 mm), see Figure 4. When a wear bar isflush with the tread surface, the tire is worn out andit is time to replace it.

Consumers should check their tire tread andsidewall areas during monthly inflation pressurechecks, looking for uneven or irregular tread wear,cuts, cracks, scrapes, snags, bulges, foreign objectsor other damage.

A manual published by the Tire Industry Association(TIA) entitled, “Passenger and Light Truck TireConditions Manual,” may be used by service garages,tire dealers, state motor vehicle inspection stations,etc., as a reference for inspection of tires, rims, andwheels.

RReeaassoonnss ffoorr TTiirree,, RRiimm//WWhheeeell oorr VVaallvvee RReemmoovvaall - Ifany of the conditions below are found wheninspecting a tire, rim/wheel or valve, the itemshould be removed from service. (Note: this list isnot all-inclusive.)

Tread Conditions• Worn to 2/32” (1.6 mm) or less anywhere on

the face of the tread and/or tread wearindicators showing

• Localized spot wear due to separation• Cuts, cracks, bulges, or snags in the tread or

groove exposing cord or fabric material(excludes repairable conditions)

• Unrepairable punctures

Sidewall Conditions• Impact break (e.g. rim bruise break) • Bulges, blisters or deep cuts/cracks • Excessive sidewall abrasion • Exposed cords or fabric material

Bead Conditions• Sharply bent or broken beads or bead wires• Deep cuts/cracks • Torn or severely chafed bead covers exposing

fabric or wire• Excessive rim flange grooving

Innerliner Conditions• Exposed body ply cords • Unrepairable punctures• Previous improper repairs • Foreign object damage • Cracking with visible cord material • Run flat damage as exhibited by abrasions,

cracking, blisters, wrinkles, discoloration, orbreakdown of cord material

Rim/wheel and valves should be removedfrom service and replaced if any of thefollowing are found:

Chapter 2, Page 17

5 Refer to Code of Federal Regulations: 49 CFR 570.62 and 49 CFR 393.75(b)


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Driving on damaged tires is dangerous. Adamaged tire can suddenly fail leading tosituations that may result in serious personalinjury or death. Tires should be regularlyinspected by a qualified tire service professional.

• Any rim/wheel that is bent, dented, cracked,excessively corroded or otherwise damaged

• Damaged valve and/or valve core

CCoommmmoonn TTyyppeess ooff TTiirree DDaammaaggee - Several types oftire damage are covered in this section. However, itis not all-inclusive and should only be used as ageneral guideline for identifying a variety of damageconditions. Refer to TIA's “Passenger and Light TruckTire Conditions Manual” for additional information.

UUnnddeerr IInnffllaattiioonn aanndd//oorr OOvveerr LLooaaddiinngg DDaammaaggeeUnder inflation and/or over loading is the leadingcause of tire failure, so it is important to maintaininflation pressure and to properly load the vehicle.See “Proper Tire Inflation” on p. 13 and “Tire Loading“on p. 16.

Under inflation and/or over loading of a tire causesexcessive heat build-up and internal structuraldamage. This may cause a tire failure, includingtread/belt separation, even at a later date, whichcan lead to an accident and serious personal injuryor death.

It is important to inspect tires for under inflationand/or over loading damage such as internal tireseparation, heat discoloration, cracking, rim flangegrooving, and localized accelerated treadwear (spotwear).

RRooaadd HHaazzaarrdd DDaammaaggeePunctures, cuts, snags, etc., can lead to furtherdamage if not repaired in time. The tire must bedemounted and carefully inspected to determinewhether it is repairable. Some road hazard damagemay result in gradual inflation pressure loss. If notcorrected as soon as possible, such damage can ruintires that could otherwise have been repaired. Forinformation on proper tire repair, see “Proper TireRepair” on page 24.

IImmppaacctt DDaammaaggeeImpact damage to the tire may initially show little orno exterior evidence. However, internal damage canprogress with additional mileage and eventuallycause internal tire separation, detachment orsudden loss of inflation. Impact damage may causegradual inflation pressure loss. After experiencingan unusual impact, have the tire inspected by a tireservice professional.

A rim bruise break (pinch shock) occurs when thetire strikes a rigid object (like a curb or pothole) hardenough to crush the tire's sidewall between the rimflange and the rigid object. Vehicles operated off-road or in areas away from paved roads canencounter many objects that can cause tire damage.Careful inspection of the tires should be made afteruse in off-road service.

DDeemmoouunnttiinngg oorr MMoouunnttiinngg DDaammaaggeeTires that have been damaged by improperdemounting/mounting procedures may failprematurely. For instance, a torn bead may causegradual inflation pressure loss and even lead tointernal tire separation. See RMA wall chart,“Demounting and Mounting Procedures for Passengerand Light Truck (LT) Tires.” Also see RMA TireInformation Safety Bulletin, Vol. 43, “Avoid Tire BeadDamage on Tire Mounting Machines that Secure theRim from Underneath.”

OOzzoonnee CCrraacckkiinngg oorr WWeeaatthheerr CChheecckkiinnggWeather checking/ozone cracking can occur duringdirect and extended exposure to damaging effects ofthe environment, such as ozone and heat fromsunlight. Ozone cracking can also be caused byexposure to electric motors, welding equipment, orother ozone generating sources. Ozone levelsshould not exceed 0.08 ppm (parts per million).

Tires with severe weather checking/ozone crackingor any cracking extending to the tire casingcords/plies should be removed from service. Formore details on storing mounted and unmountedtires, see “Tire Storage Recommendations” on p. 26.

Treating tires with incompatible dressings or harshcleaning agents will hasten oxidation and result inpremature cracking. Always avoid petroleum-basedtire dressings/cleaners. Check with the tiremanufacturer recommendations for cleaning tires.See “Cleaning Tires” on p. 27.

Tire Service Life

It is important to have tires in good operatingcondition, thus tires may need to be replacedbecause of service conditions long before the treadis worn out. To determine if tires, including thespare, should remain in service, it is recommended

Tire Maintenance Manual

Chapter 2 , Page 18


Chapter 2, Page 19

Common Examples of Tire Damage

Run Flat (w/Breakage) Run Flat Run Flat

Tread/Belt Separation

Bulge - Exterior Rim Bruise (Pinch Shock)

Scuff/Curb Damage Tread (Crown) Break Tread (Crown) Break

Tread/Belt Separation

Bead Cut/Tear Ozone/Weather Cracking

Sidewall Break

Diagonal Cracking


Sidewall SeparationSidewall Separation

Puncture

Improper Repair (Plug Only)

that they be periodically inspected by a tire serviceprofessional during routine maintenance intervalslike oil changes and tire rotations. The service life oftires includes their overall condition and vehicleusage factors, not just tread wear. All of thesefactors should be taken into account whenconsidering tire replacement.

Follow the vehicle and tire manufacturers’ specificrecommendations, if any, regarding tire service lifeand replacement. In order to determine the age ofthe tire, look for the last four digits of the DOT tireidentification number (see Chapter 1, "Basic TireInformation" for details). For example, a tire with aDOT tire identification number ending with the last4 digits of 0309 indicates it was manufactured the3rd week of 2009.

Tires that have been permanently removed fromservice should be rendered unserviceable anddestroyed so no one else can use them.

Tire Service Life is Not Determined by

Chronological Age - Tires are composed ofvarious materials, including rubber, havingperformance properties essential to the properfunctioning of the tire. These component propertiesevolve over a combination of time, service andstorage conditions. For each individual tire, thischange is affected by many elements such astemperature, storage conditions, and conditions ofuse (e.g., load, speed, inflation pressure, impactsand road hazard injury) to which a tire is subjectedthroughout its life. Since service and storageconditions vary widely, accurately predicting theservice life of any specific tire based on calendar ageis not possible. RMA is not aware of scientific ortechnical data that establishes or identifies a specificminimum or maximum service life for passengerand light truck tires. However, in some cases a tireor vehicle manufacturer may make a specific tire

replacement recommendation regarding itsproducts. If so, the consumer should consult themanufacturer with any questions with regard tofollowing the recommendation. Furthermore, anysuch recommendation should not be considered aminimum service life for the tire.

Tire Rotation

Before rotating tires, always consult the vehicleand/or tire manufacturer for specificrecommendations regarding rotation. The purposeof regularly rotating tires is to prolong tread lifeand promote more uniform tread wear for all tireson a vehicle. If no rotation period is specified, tiresshould be rotated every 5,000 to 8,000 miles (or perthe tire manufacturers recommendations) or at anysign of uneven wear. The first rotation is the mostimportant. Going for extended mileage, where thetires are not rotated, can result in a situation wherea pair of tires wears prematurely and unevenly. Iftires show uneven tread wear, check for andcorrect any misalignment, imbalance, or othermechanical problems before rotation.

Any vehicle showing a tendency for weardifferential should have tires rotated more often.Always consult the vehicle and/or tiremanufacturer for specific rotation instructions.

Many vehicle manufacturers recommend replacingall tires on the vehicle at the same time. Thismakes rotation even more important formaintaining uniform tread depth and optimumtread wear of the entire set.

In the absence of vehicle manufacturer rotationrecommendations, follow the rotation patterns inFigure 5. Note that certain types of tires cannot berotated in the manners shown. Such tires mayinclude directional and asymmetrical tires. Also,some vehicles may have different sized tiresmounted on the front and rear axles, and thesedifferent sized tires have rotation restrictions. Forthese special cases, check the recommendations inthe vehicle owner's manual for proper rotation.

When tires are rotated, the inflation pressures mustbe adjusted for the tires' new positions inaccordance with the vehicle manufacturer's


Chapter 2, Page 20


Chapter 2, Page 21

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FRONT

VVeehhiicclleess wwiitthh DDuuaall RReeaarr WWhheeeellss ((SSiixx--TTiirree RRoottaattiioonn))

FRONTFRONTFRONT

All Vehicles

FRONT

FRONT

Rear and Four Wheel Drive Vehicles

Rear and Four Wheel Drive Vehicles

with Full Size Spare TireFront Wheel Drive Vehicles

with Full Size Spare Tire

Front Wheel DriveVehiclesAll Vehicles

FRONT FRONT

Full SizeSpare

Full SizeSpare

FRONT FRONT

Rear Tire Irregular Wear Front Tire Irregular Wear

recommendations; see the vehicle tire placard,certification label, or owner’s manual. Underinflation may result in rapid and/or abnormaltreadwear, improper vehicle handling anddecreased fuel economy. Over inflation can alsoresult in rapid and/or abnormal tread wear,decreased traction and premature wear ofsuspension components. Improper tire inflation maycause a tire failure, including tread/belt separation,even at a later date, which can lead to an accidentand serious personal injury or death. See “ProperTire Inflation” on p. 13.

Do not include a "Temporary Use" or T-type sparetire in any of these rotation patterns. If the vehiclehas a matching full-size spare tire, it isrecommended that it be included in the tirerotation. Use one of the tire rotation patternsillustrated, inserting the full-size spare at the rightrear position. Always check and adjust the inflationpressure of the full size spare when incorporating itinto the rotation scheme.

Conditions Affecting TreadWear

Service Conditions

Tread wear is affected by many different vehicleoperating conditions. Abnormal wear typicallyresults from a combination of unsatisfactoryconditions and may make an accurate diagnosis ofthe cause(s) difficult. It is important to identify theemergence of abnormal wear in its early stage andcorrect the cause before valuable tire treadwear islost. Most of the causes of abnormal treadwear canbe corrected. The causes can include excessive tirestresses due to driving habits, road surfaces, terrainand axle position.

Driving HabitsThe way a vehicle is driven has a great deal to dowith tread wear and safety. Observe posted speedlimits and avoid hard stops, starts and cornering. Inaddition, avoid potholes, objects on the road, andcurbs (such as hitting/forcing the tire against thecurb when parking). The rate of wear increasesduring hard cornering at both high and low speedsdue to scuffing caused by lateral forces, particularly

on the front tires. Hard acceleration or braking willalso cause increased wear due to torque and weighttransfer. The tires with the most weight on them,typically the front tires, are doing the most braking.

Road Surfaces/TerrainRapid or abnormal tread wear may be caused byabrasive road surfaces such as those with sharp orcoarse highway paving materials. Areas that havenumerous hills or curves can also lead toaccelerated treadwear.

Axle PositionThe position of a tire on a vehicle determines whatstresses the tire will experience. The tires on thedrive axle are affected by acceleration. Dependingon the vehicle, this can be the rear axle, the frontaxle or, in the case of four-wheel drive, both axles.On front-wheel drive vehicles, the front axle alsosteers the vehicle and performs most of the braking.Free-rolling, rear tires may also experience someabnormal tread wear. Rotating tires on the vehiclemay help to minimize abnormal wear.

Maintenance Conditions

There is a close relationship between severalmechanical systems on a vehicle and its tires. Tires,wheels, brakes, shock absorbers, drive train,steering and suspension systems, etc., must allfunction together to perform safely and comfortablyand to give optimum tread wear. Improper orinadequate vehicle maintenance can cause tires towear rapidly and/or abnormally. All of the followingmaintenance conditions can be adjusted or repaired.

Improper Tire InflationFor optimum service, use the inflation pressuresspecified by the vehicle manufacturer on the vehicletire placard, certification label or owner’s manual.Under inflation may result in rapid and/or abnormaltread wear, improper vehicle handling anddecreased fuel economy. Over inflation can alsoresult in rapid and/or abnormal tread wear,decreased traction and premature wear ofsuspension components. Improper tire inflation maycause a tire failure, including tread/belt separation,even at a later date, which can lead to an accidentand serious personal injury or death. Check andadjust tire pressure (including the spare) at least


Chapter 2, Page 22

once per month with a pressure gauge (see “ProperTire Inflation” on page 13).

Vehicle Wheel MisalignmentIf the vehicle wheels are not properly aligned, tireswill experience stresses as if they were constantlycornering. This will cause increased and abnormaltread wear. A qualified mechanic should correctmisalignment of wheels. Front-wheel drive vehiclesand those with independent rear suspension requirespecial attention with alignment of all four wheels.For any vehicle, four-wheel alignment can identifyproblems such as “dog tracking,” when the rear tiresdo not follow in the paths of the front tires. This canalso result in abnormal tread wear. The vehiclealignment geometry should be checked periodicallyas specified by the vehicle owner's manual or ifmisalignment is suspected.

Lack of Tire RotationTire rotation procedures are established to equalizethe tread wear for each tire to prolong tread life. Byregularly changing a tire to another position on thevehicle, any abnormal wear patterns that werestarting to develop may be corrected (see “TireRotation” on page 20).

Tire and Wheel Assembly Out-of-BalanceA tire and wheel assembly that is out-of-balancecan cause abnormal tread wear due to vibration and

irregular road contact which may be worse atspecific speeds (see page 32 for information on tirewheel balance).

Damaged WheelsDamaged wheels can cause a tire to contact theroad unevenly and cause abnormal tread wear.Wheel damage may not be visually obvious andshould be checked by a tire service professionalusing proper measuring equipment.

Brakes in DisrepairIf not in proper working order, brakes can grabunevenly and cause abnormal tread wear.

Worn Struts, Shock AbsorbersA worn strut or shock absorber will not properlydampen vehicle motion and cause abnormal treadwear.

Worn or Loose Suspension and Steering Systemsand Worn Ball JointsExcessive wear and looseness anywhere in thesuspension and steering systems (such as tie-rodends and ball joints) can cause tire and wheelassemblies to move in ways in which they were notdesigned. This will cause rapid and/or abnormaltread wear.


Chapter 2, Page 23

Diagonal Wear Heel and Toe Wear One-Sided Wear

Both Shoulder Wear Center Wear Cupping Wear

Examples of Abnormal Tread Wear

Tire Worn Out Tire Worn Out

Tire Worn Out Tire Worn Out

Proper Tire Repair

Tires driven even a short distance while underinflated may be damaged beyond repair. Running atire under inflated is like running the vehicle'sengine without enough oil or coolant. It may seemto work fine for a time, but serious permanentdamage has occurred. Adding oil or coolant won'trepair engine damage, and adding inflation pressurewon't fix tire damage. The tire will remain seriouslydamaged and can still fail, even after inflationpressure is corrected.

If a tire is losing inflation pressure, a tire serviceprofessional should check the tire surface and thevalve for the source of the leak(s) by using water ora soap solution prior to demounting the tire from therim. Mark the injured area and totally deflate thetire. Then remove the tire from the wheel beingcareful to avoid further damage to the tire,particularly to the bead area. Perform a completeinternal inspection.

For vehicles equipped with dual tire assemblies(duals), if one of the dual tires becomes significantlyunderinflated or flat, the other tire will carry the loadfor both tires, resulting in an overloaded condition.Both tires should be inspected by a tire serviceprofessional for damage. See Tire InspectionGuidelines on p. 16.

Always read, understand and follow the RMA wallchart "Puncture Repair Procedures for Passenger andLight Truck Tires" which covers the proper repairprocedures for passenger and light truck tiresthrough Load Range "E." Never repair a tire with aninjury that is greater than ¼ inch (6mm) in diameter.Do not repair an injury outside the puncture repairarea as shown in Figure 6.

The basic principles for proper puncture repair:

• Remove the tire from the wheel for inspection and repair;

• Prepare the injured area;• Fill the injury with a suitable, vulcanizing material

or rubber stem that must fill the injury and keepmoisture out;

• Seal the innerliner with a patch to prevent loss ofinflation and keep moisture out; and,

• Re-inspect the finished repair.

Refer to the RMA wall chart for complete step bystep procedures.

Not all tires can be repaired. In addition to the RMApuncture repair procedures, there may be additionallimitations based on individual tire manufacturerrepair policies. These may include the type of servicesuch as speed rating, load index, run-flat technologyand commercial application. When repairing a tirepuncture:

• Never perform a tire repair on-the-wheel • Never use only a plug (stem)• Never use only a patch


Chapter 2, Page 24

Puncture repairs are limited to the tread area as generallydepicted above. DO NOT make repairs where the injurydamage extends into the shoulder/belt edge area OR wherethe injury extends at an angle into the shoulder area. If thereis any question that the injury extends into the shoulder/beltedge area, then the tire must be scrapped.

FFiigguurree 66:: PPuunnccttuurree RReeppaaiirr AArreeaa

Improperly repaired tires can fail while in service,such as by tread/belt separation, which can leadto an accident and serious personal injury ordeath.

Tires must always be properly repaired asdescribed in the RMA wall chart, “Puncture RepairProcedures for Passenger and Light Truck Tires.”

PUNCTUREREPAIRAREA

VVeehhiiccllee OOrriiggiinnaall EEqquuiippmmeenntt TTeemmppoorraarryy TTiirreeMMoobbiilliittyy KKiittssA temporary tire mobility kit may be supplied by thevehicle manufacturer as an alternative to a spare orrunflat tire in passenger car and light truckapplications. The temporary tire mobility kit isnormally comprised of a puncture sealant and asmall air compressor or container of propellant.

Use of a temporary tire mobility kit:

• Is not considered a repair to the tire

• Only provides a temporary solution to promptlyreach a service location for professionalinspection and possible repair of the affected tire.Refer to tire manufacturer for specific guidelinesregarding repairability and warranty.

End-users of temporary tire mobility kits supplied asoriginal equipment in a passenger car or a lighttruck vehicle should always follow all instructionsprovided by the vehicle manufacturer, includinglimits on the amount of driving at reduced speedsallowed to safely reach a tire service location.

AAfftteerrmmaarrkkeett SSeeaallaannttss The RMA does not endorse aftermarket sealantproducts. Aerosol, liquid, gel or other substancesinjected into a tire through the valve are notconsidered proper repairs. Such products may beflammable and potentially explosive, may damagethe tire, may void the tire manufacturer's warrantyand may interfere with or damage tire pressuremonitoring system sensors.

Consult the tire manufacturer's servicerecommendations and warranty policy. See "TireExplosions and Flammable Substances" on p. 28.

Chapter 2, Page 25


If a tire continually loses inflation pressure or haslost all or most of its inflation pressure, it must beremoved from the wheel for a complete internalinspection to check for damage. Driving ondamaged tires is dangerous. A damaged tire cansuddenly fail, including by tread/belt separation,even at a later date, which can lead to an accidentand serious personal injury or death.

Never perform a tire repair without removing thetire from the wheel assembly for an internalinspection. Do not perform an outside-in tirerepair or an on-the-wheel repair.

The photo above is an example of a tire that wasoperated in an underinflated condition with apuncturing object that caused dangerous, non-repairable damage to the innerliner and body plymaterial. This type of damage would not havebeen visible from the outside of the tire.

Every tire must be removed from the wheel for aninspection and to assess repairability.

Tire changing can be dangerous and should bedone by trained personnel using proper tools andprocedures. Always read and understand anymanufacturer’s warnings contained in owner’smanuals, on the equipment, listed on websitesand molded onto tire sidewalls.

Failure to comply with these procedures mayresult in faulty positioning of the tire and/or rimparts and cause the assembly to burst withexplosive force sufficient to cause seriousphysical injury or death. Never mount or usedamaged tires or rims.

For more information on tire mounting safetyand procedures, refer to the RMA wall chart“Demounting and Mounting Procedures forPassenger and Light Truck (LT) Tires.”

Passenger and Light TruckUsed Tires6

This information pertains to used passenger andlight truck tires installed as replacement tires or asequipped on a used vehicle.

Once tires are applied to a vehicle and put intoservice (this includes spare tires), they areconsidered “used.” There is a potential riskassociated with the installation of used tires thathave uncertain or unknown history of use,maintenance or storage conditions. Such tires mayhave damage that could eventually lead to tirefailure.

Not all tire damage that can lead to tire failure isoutwardly visible. For instance, improper repairs ordamage to a tire’s innerliner can only be observed byinspecting the inside of the tire, demounted from thewheel. A qualified tire service professional shouldinspect the internal and external condition of theused tires prior to application. In the case of a usedvehicle purchased by a consumer, the only way todetermine the condition of its tires is to have themdemounted by a tire service professional for thesame type of inspection.

Spare Tire Maintenance

Spare tire (full-size and temporary spare) inflationpressure should be checked monthly and before anylong trips. Use an accurate gauge. T-type temporaryspare tires require 60 psi (420 kPa). When adjustinginflation pressure in T-type tires, do so in smallamounts since the tire is smaller and the pressurelevel changes rapidly. Do not over inflate.

Inspect the spare tire/rim/wheel periodically (i.e.during tire rotation intervals) for any visible damageto the tire or corrosion on the wheel.

If the vehicle has a matching full-size spare tire, itis recommended that it be included in the tirerotation. Always check and adjust the inflationpressure of the full size spare when incorporating itinto the rotation scheme.

Tire StorageRecommendations7

Stored tires should be protected againstenvironmental effects such as sunlight, high heat,ozone and other potentially damaging conditions.

• Store tires where the area is clean, dry and wellventilated, but with a minimum of circulating air.

• Store tires in an area with temperate ambientconditions (mild temperatures, shaded or dark).

• Store tires raised off a storage area's floor surfaceto minimize exposure to moisture or damage.

• Avoid contact with petroleum-based productsand/or other volatile solvents or substances.

• Store tires away from electric motors, batterychargers, generators, welding equipment or otherozone generating sources.


Chapter 2, Page 26

6 Refer to RMA Tire Information Service Bulletin, Vol. 45, “Passenger and Light Truck Used Tires.”

7 Refer to RMA Tire Information Service Bulletin, Vol. 23, “Tire Storage Recommendations.”


T-type temporary spare tires should only be usedwith rims/wheels specifically intended for them.

Rims/wheels intended for use with T-type tiresshould not be used with any other types of tires.

A temporary spare tire and wheel assemblyshould never be used on a vehicle with which it isnot compatible. Never use more than onetemporary spare tire at a time.

Indoor storage is recommended, however if tiresmust be stored outdoors:

• Store tires where they are raised off the ground (oron storage racks) and not in contact with heatabsorbent surfaces.

• Protect tires with an opaque, waterproof coveringwith some type of vent openings to avoid creatinga "heat box" or "steam bath" effect.

IIff ttiirreess aarree mmoouunntteedd oonn aa ssttoorreedd vveehhiiccllee::Store the vehicle such that all weight is removedfrom the tires. If vehicle weight cannot be removed,unload the vehicle to minimize the weight. Maintainthe recommended tire inflation pressure, includingthe spare. The surface where parked/stored shouldbe firm, reasonably level, well drained and clean.Vehicle should be moved every three (3) months sothe tire flex area is changed.

RReettuurrnniinngg ttiirreess ffrroomm ssttoorraaggee bbaacckk ttoo sseerrvviiccee::Before placing stored tires back into service, a tireservice professional should conduct a visual andtactile inspection to be sure each tire is clean, dry,free of foreign objects, and/or does not show signsof damage. See “Tire Inspection Guidelines” on p. 16.Once mounted on a rim/wheel, the tire (includingthe spare tire) should be inflated to therecommended inflation pressure. See “Proper TireInflation” on p. 13.

Cleaning Tires

Clean tires with soap and water and a soft bristlebrush or a shop cloth. Treating tires withincompatible dressings or harsh cleaning agents willhasten oxidation and result in premature cracking.Never use petroleum-based products as tiredressings/cleaners. Use of a pressure washer orsteam cleaner may be damaging to the tire.

Tire Sidewall Indentations8

The condition, sometimes referred to as sidewallundulations, is a common characteristic of radialtire construction (see Figures 7 and 8). Theseindentations are more noticeable in tire sizes with higher aspect ratios and/or higher inflationpressures.

In a radial tire the body ply cords run straight acrossthe tire from bead to bead. The joining of the plymaterial creates a narrow overlap of ply cords in theradial direction at each junction. These overlappedply cords slightly restrict the natural expansion ofthe sidewall when inflated. This results in anindentation. Since the belt plies reinforce the tread,only the sidewalls are indented.

Sidewall indentations are a cosmetic characteristicand will not affect the performance of the tire. Ifbulges, rather than indentations, appear on thesidewall or if there is any question concerning thesidewall appearance, the tire should be examined bya tire service professional.

Chapter 2, Page 27

8 Refer to RMA Tire Information Service Bulletin, Vol. 21, “Sidewall Indentations in Radial Tires.”


FFiigguurree 77:: SSiiddeewwaallll IInnddeennttaattiioonn

FFiigguurree 88:: RRaaddiiaall BBooddyy PPllyy OOvveerrllaapp

Tire Explosions andFlammable Substances9,10

Inflation pressure in a tire represents tremendouspotential energy. If improperly treated, a tire canexplode, suddenly releasing the stored-up energywhich may result in serious injury or death. Causesfor tire/wheel assembly explosions can include:

• Tire damaged during mounting/demounting• Tire mounted on wrong size rim• Improper mounting/demounting procedures• Use of flammable solvents during tire mounting or

to seat beads • Exceeding tire maximum pressure limitation• Flammable liquids or vapors introduced into the

tire including sealents and aerosol inflators• Welding, heating, or brazing an inflated

tire/wheel assembly• Improper tube fitment and pinching of the tube

between the rim and tire during inflation• Re-inflating a tire which has been run in an

under inflated or over loaded condition• Tire damaged in service or improperly repaired

and reinflated• Exceeding rim maximum pressure limitation • Brake over heating

Avoid flammable vapors inadvertently beingpumped into a tire when the tire is inflated.

• Do not use alcohol, methanol, dry gas or any otherflammable material in the compressor tank toprevent freezing or condensation.

• Do not store flammable solvents or rubber cementsnear the intake of the compressor.

• Do not clean the compressor intake screen/filterwith flammable solvents such as gasoline.

• Do not use a battery charger near the compressorintake. This can result in hydrogen gas being drawninto the compressor.

Locate compressor indoors where freezing will notoccur and in an area by itself away from operationssuch as tire repairing, battery charging, etc. Eachday, open the bleed valve on the tank to expelmoisture. Add a filter, trap, or dryer to thecompressor to remove moisture.

AAfftteerrmmaarrkkeett SSeeaallaannttss//IInnffllaattoorrssFlammable propellants and/or liquids inaftermarket sealants or aerosol inflators may causea tire to explode under certain circumstances. Neverintroduce a flammable substance into a tire. Tireservice professionals should assume that anyaftermarket product used to seal or inflate a tire isflammable. In addition to following properdemounting procedures (see p. 29), take thefollowing precautions:

• Keep the tire away from heat, flame, sparks orother ignition sources.

• Use tools with caution, particularly tire irons,reamers and hammers, to avoid causing sparks.

• In a well-ventilated area--and with the tiresecured to a vehicle, tire mounting machine orother restraining device--remove the valve coreand completely deflate the tire.

• Re-inflate and deflate the tire a few times tofurther dissipate and expel potentially flammablevapor.

9 Refer to RMA Tire Information Service Bulletin, Vol. 3, “Tire Explosions Caused by Tire Spinning.”10 Refer to RMA Tire Information Service Bulletin, Vol. 41, “Tire Bead Lubricants, Mounting Aids, Bead Sealers, OEM Mobility Kits, Tire Sealants, Balancing

Substances and Flammable Substances.”


Chaper 2, Page 28

Never, under any circumstance, introduce aflammable substance into a tire.

Igniting this substance in an effort to facilitateseating the beads is extremely unsafe. This mayresult in an explosion of the tire with forcesufficient to cause serious personal injury ordeath.

This practice may also result in undetecteddamage to the tire or rim that could result infailure of the tire in service.

Serious injury or death may result from anexplosion of the tire and rim/wheel assembly dueto heating the rim/wheel. Never rework, weld,braze or heat a wheel or rim.

Tire Spinning11

The centrifugal forces created by a rapidly spinningtire can cause an explosion by literally tearing thetire apart. These forces act on the complete tirestructure, and can be of such magnitude as to breakthe beads in addition to rupturing the tire. Somevehicles are able to bring a tire to its centrifugalforce failing point in just 3 to 5 seconds.

• When stuck on ice, snow, mud, or wet grass, thevehicle should be rocked gently (alternately usingforward and reverse gears) with the least amount ofwheel spinning. Repeatedly shift the gear leverfrom drive to reverse on automatic transmissionsor reverse to second on manual transmissions,while applying gentle pressure to the accelerator.Vehicles with ABS or traction control systemsneed to follow the instructions in their owner'smanual.

• Never exceed 35 mph (56 km/h) indicated speedon the speedometer.

• Never allow anyone to stand near a spinning tire.

Mounting and DemountingProcedures

For detailed instructions on mounting passengerand light truck tires, refer to the RMA wall chart“Demounting and Mounting Procedures for Passengerand Light Truck (LT) Tires.” Read and understand theprocedures and safety warnings before proceeding.

For additional information on mounting low aspectratio, high performance passenger and light trucktires, refer to RMA Tire Information Service Bulletin,Vol. 46, “Proper Tire Mounting of Low Aspect Ratio,High Performance Passenger and Light Truck Tires.”

TTiirree BBeeaadd LLuubbrriiccaannttss UUsseedd ttoo MMoouunntt TTiirreess -- Usecommercially available lubricants made for beadseating to seat tire beads. Also, vegetable oil andanimal soap solutions may be used. If a lubricant iswater-based, it should contain a rust inhibitor. Careshould be exercised to avoid excessive applicationof lubricant to minimize moisture in the pressurechamber. Do not allow any lubricant to run betweenthe tube and casing in tube-type tires or on theinside surface of tubeless tires. When dry, thelubricant should not remain slippery.

TTiirree MMoouunnttiinngg AAiiddss aanndd BBeeaadd SSeeaalleerrss -- Somemounting aids (such as rubber "O" rings or "donuts")can become trapped between the tire bead and rimduring mounting. This prevents the bead fromproperly seating on the rim, which can lead tofailure.

Bead sealers may also impede bead seating ifallowed to dry on beads and rim contact surfacesbefore mounting.

VVaallvvee MMaaiinntteennaannccee1122 -- Always remove and replacesnap-in valves when replacing tires. Never reusesnap-in valves. Only valves that are compatible withthe rim being serviced should be used.

Always cover the valve stem with a sealing cap. Thishelps prevent moisture, dirt and other contaminants


Chapter 2, Page 29

11 Refer to Tire Information Service Bulletin, Vol. 3, “Tire Explosions Caused by Tire Spinning.”12 Refer to Tire Information Service Bulletin, Vol. 40, “Tubeless Type Valves for Passenger and Light Truck Tires Including Tubeless Snap-In Tire Valve InstallationProcedure.”

Excessive speed in a free-spinning tire can causethe tire to explode from extreme centrifugalforce. The energy released by such an explosionis sufficient to cause serious physical injury ordeath.

Never spin a tire above a speedometer reading of35 mph (56 km/h). Never stand near a spinningtire.

NOTEOnly mount tires on approved rim widths.

from entering the valve core as well as providing anadditional seal. Any time a tire is demounted for anyreason (including repairs), inspect the valve stem fordamage (crack, tears, etc.) to determine if the valvestem should be replaced. For inflation pressuresabove 65 psi (450 kPa), a high-pressure valve mustbe used. The proper valve must be used for theparticular tire/wheel application.

Tire/wheel assemblies that are equipped with a tirepressure monitoring system (TPMS) may have asensor that is attached to or is part of the valve

assembly. When new tires are installed it isrecommended to also replace all components that areincluded in the TPMS valve replacement kit. Inaddition, whenever the sensor is disassembled for anyreason, install a new TPMS replacement kit. Alwaysreplace any damaged sensor.


Chapter 2, Page 30

NOTEIf the TPMS valve is replaced by a conventional

valve, the TPMS will not function.

Tire changing can be dangerous and should be done by trained personnel using proper tools andprocedures. Always read and understand any manufacturer’s warnings contained in owner’s manuals, onthe equipment, listed on websites and molded onto tire sidewalls.

Failure to comply with these procedures may result in faulty positioning of the tire and/or rim parts andcause the assembly to burst with explosive force sufficient to cause serious physical injury or death. Nevermount or use damaged tires or rims.

For more information on tire mounting safety and procedures, refer to the RMA wall chart “Demounting andMounting Procedures for Passenger and Light Truck (LT) Tires.”

NEVER INFLATE BEYOND 40 PSI TO SEAT BEADS.NEVER STAND, LEAN, OR REACH OVER THE ASSEMBLY DURING INFLATION.

Inspect both sides of the tire to be sure that the beads are evenly seated. If tire is mounted on a machinethat does not have a positive lock-down device to hold the wheel, inflation should be done in a safety cageor other restraining device. If both beads are not properly seated when pressure reaches 40 psi, completelydeflate the assembly, reposition the tire and/or tube on the rim, relubricate, and reinflate.

Inflating beyond 40 psi inflation pressure when trying to seat the beads is a DANGEROUS PRACTICE thatmay break a tire bead (or even the rim) with explosive force, possibly resulting in serious injury or death.After the beads are fully seated, pressure may be increased above 40 psi to operating pressures, as shownon the vehicle placard but not to exceed the maximum molded on the tire sidewall.


Chapter 2, Page 31

There is a danger of serious injury or death if a tire of one bead diameter is installed on a rim or wheel of adifferent rim diameter. Always replace a tire with another tire of exactly the same bead diameter as thediameter of the rim on which it will be mounted.

For example: a 16” tire goes on a 16” rim. Never mount a 16” tire on a 16.5” rim. A 16.5” tire goes on a 16.5”rim. Never mount a 16.5” tire on a 16” rim. While it is possible to pass a 16" diameter tire over the lip or flangeof a 16.5” size diameter rim, it cannot be inflated enough to position itself against the rim flange. If an attemptis made to seat the tire bead by inflating, the tire bead will break with explosive force and could cause seriousinjury or death.

Rims of different diameters and tapers cannot be interchanged. The following diagram illustrates thedifference between rims of two different tapers and diameters:

The following diagram shows how beads of a 16” tire will not seat on a 16.5” rim. The beads cannot be forcedout against the rim flanges by using more inflation pressure because this will break the beads and the tire willexplode with force sufficient to cause serious injury or death.

Silicone, petroleum, or solvent-based lubricantsmust not be used. These substances may:

• cause the tire to slip on the rim.• have a harmful effect on the tire, tube, flap

and/or rim.• create explosive mixtures of air and vapors in

the tire which may result in serious injury ordeath.

Never, under any circumstance, introduce aflammable substance into a tire.

Igniting this substance in an effort to facilitateseating the beads is extremely unsafe. This mayresult in an explosion of the tire with forcesufficient to cause serious personal injury ordeath.

This practice may also result in undetecteddamage to the tire or rim that could result infailure of the tire in service.

Tire/Wheel Balancing andInstallation

Tire/wheel balance is important for proper tire treadwear. Out-of-balance conditions may reduce tiremileage significantly and can be the source ofvehicle vibration and bounce. Maintainingtire/wheel balance over the service life of the tirehelps to maximize the tire's performance.

There are two types of out-of-balance conditions fortire/wheel assemblies that cause vibration athighway speeds. See Figure 9. Static balance, alsoknown as single plane balance, may result invibration due to vertical (up and down) movement.It can be corrected using a bubble or spin balancer.Uneven distribution of weight across another axis ofthe wheel causes vibration due to rotationalmovement (wobble or shimmy). It can only becorrected using a dynamic spin balancer which alsocan correct static imbalance.

DDyynnaammiicc CCoommppuutteerr--CCoonnttrroolllleedd BBaallaannccee MMaacchhiinneeSSeett--uupp aanndd UUssaaggee -- Tire/wheel service centers usingdynamic spin balancing machines establish theoptimal balance of the tire/wheel assembly by correcting both types of imbalance. Only trained tireservice professionals should perform tire balancing.Balancing equipment should be properly set up andcalibrated with particular attention to the wheelassembly alignment (e.g. hub-centric or lug-centricwheels). With larger passenger and light truck tires,flange plate adaptors may be required to obtainaccurate tire/wheel balance.

TTiirree//WWhheeeell AAsssseemmbbllyy IInnssttaallllaattiioonn -- Consult thevehicle owner's manual for recommendations ontire/wheel assembly installation. Identify lug torquespecifications for proper installation. It isrecommended that lug nuts and bolts be tightenedto exact torque specifications with a torque wrench.Improper torque, either too loose or too tight, maycause loss of lug nuts, breaking of the stud(s),damage to the tire/wheel assembly, or detachment of the tire/wheel assembly from the axle. Never useair tools to install custom wheels. Always use atorque wrench for final tightening and followaccepted tightening (torquing) procedures.


Chapter 2, Page 32

FFiigguurree 99:: TTwwoo TTyyppeess ooff TTiirree//WWhheeeell IImmbbaallaannccee

Serious injury or death may result from explosionof tire and rim/wheel assembly due to impropermounting.

• Never exceed 40 psi (inflation pressure)when seating beads.

• Always use a safety cage or other restrainingdevice with a clip-on extension hose.

• Only specially trained persons should mounttires.

.

TIRE SEALANTS AND BALANCING SUBSTANCES

Solvent-based liquids must not be used due tothe possibility of creating explosive mixtures ofvapors in the tire, which may result in seriousinjury or death.

Ride Comfort OptimizationProcedures and Diagnostics

Tire Manufacturer Match-Mount Markings -- Newtires are often marked by the manufacturer toindicate the location (known as the “high point”)that should be matched to a particular location on awheel. The marking is generally a colored-spot onthe sidewall. It should be matched to a location onthe wheel (known as the “low point”) often at ornear the valve.

Consult with the tire manufacturer for the meaningof match-mount markings and recommendationsfor match-mounting to wheels.

Match-Mount Balancing Machines -- Consumerexpectations and increased sensitivity of vehicleshave resulted in additional procedures to produce asmooth, quiet ride. Modern ride optimizationmachines may be used to resolve manyride/vibration complaints.

These machines have the capability of evaluatingthe tire/wheel assembly and the wheel alonefollowing prescribed match-mounting procedures.Match-mounting techniques can minimizepotential vibration. Wheel measurements canhighlight possible wheel irregularities. Use of thesemachines can assist with diagnosis of tire/wheel-related vibration complaints.

However, match-mounting balancing machines arenot laboratory or factory-grade tire unformitymeasurement machines and should never be usedto screen new tires for uniformity. Consult the tiremanufacturer for their policy regarding tiresevaluated using match-mount balancing machines.

Manual Ride Optimization Procedure (ManualRun-Out Method) - Follow these steps to manuallydiagnose a tire/wheel assembly suspected ofcausing vibration:

1. Test drive the vehicle to determine where thevibration is originating.

2. Place the suspect tire and wheel assembly on thebalance machine and check its balance. Correct ifnecessary and test drive the vehicle again.

3. If the balance is acceptable and the vibration isstill present, next check the tire and rim for run-out.

a. Place the suspect tire and wheel assemblyon the balance machine.

b. Place a run-out gauge or dial indicator inthe center of the tire tread. Set the gauge atzero.

c. Slowly rotate the tire and rim assembly 360degrees. While rotating, observe the gaugeand determine the location of greatest run-out. Mark that location on both the tire treadand wheel.

d. Deflate the tire and rotate it, until the markon the tire is exactly opposite from the markon the wheel (180 degrees).

e. Reinflate the tire. Recheck the tire/wheelassembly run-out by slowly rotating theassembly 360 degrees.

f. If the run-out has been reduced, install thetire/wheel assembly on the vehicle andperform a test drive. If the run-out has notbeen reduced, find the peak run-out. If thepeak run-out is located near the area wherethe rim was originally marked, the rim maybe the cause. Consult the rim manufacturer.If the peak run-out is located near the areawhere the tire was marked, the tire may bethe cause of vibration. Consult the tiremanufacturer.


Chapter 2, Page 33

NOTETo confirm the run-out of the rim, it may benecessary to demount the tire and check the rimwith a run-out gauge indicator against each beadseat ledge.

”Zipper Ruptures” in SteelCord Radial Medium andLight Truck Tires

The following applies to tires with steel cordcasings.

Any inflated tire suspected of having been operatedunder inflated and/or over loaded must beapproached with caution. A tire service professionalmust remove the valve core and completely deflatethe tire before removing the tire/wheel/rimassembly from the vehicle. Clearly mark the tire inan appropriate manner indicating it has been rununder inflated and is a potential for a zipper rupture.Do not return the tire to service without followingproper procedures, including an inspection by a tireservice professional. See RMA Tire InformationSafety Bulletin, Vol. 33, “Inspection Procedures toIdentify Potential Sidewall ‘Zipper Ruptures’ in SteelCord Radial Truck, Bus, and Light Truck Tires.”

Chapter 2, Page 34

A grazing light orother indirect lightsource usedduring inspectioncan revealshadows of anysidewallirregularities thatare signs of apotential zipperrupture.

An example of anactual zipperrupture. Note thecharacteristic“zipper-like” seamalong the sidewallwhere the ruptureoccured.

Any steel cord radial tire suspected of operatingunder inflated and/or over loaded must beapproached with caution. Permanent damagedue to operating a tire under inflated and/or overloaded cannot always be detected. Any tireknown or suspected of being operated at 80percent or less of normal operating inflationpressure and/or over loaded could possibly havepermanent sidewall structural damage (steel cordfatigue).

Ply cords weakened by under inflation and/orover loading may break one after another, until arupture occurs in the upper sidewall withaccompanying instantaneous pressure loss andexplosive force. This can result in serious injuryor death.

See RMA Tire Information Safety Bulletin, Vol. 33,“Inspection Procedures to Identify Potential Sidewall‘Zipper Ruptures’ in Steel Cord Radial Truck, Bus,and Light Truck Tires.”


Tire Retreading

While retreading tires is predominantly a practiceused for commercial truck and bus tires, there aresome companies that retread light vehicle tires.Note that it takes special equipment and expertise toretread passenger car and light truck tires. For moredetailed information on retreading passenger andlight truck (LT) tires, refer to the RMA Shop Bulletins fortire retreading and tire repairing.


Chapter 2, Page 35

NOTEDon’t sell, use or retread tires whose originalDOT marking/serial number has been removed,obliterated or branded over.

Tire Replacement Guidelines

Chapter 3, Page 36

CSPLT3-0811

CHAPTER 3 (OF A 4 CHAPTER SERIES)

TIRE REPLACEMENTGUIDELINES

Overview

The purpose of this chapter is to provide tire industryrecommended guidelines and important safetyinformation when replacing tires for light vehicles.13

While this chapter is intended to outline generalguidelines and considerations for tire replacement, itis not all-inclusive. Questions pertaining to specificproducts and/or vehicle fitments should be addressedto the vehicle manufacturer, tire manufacturer, or tiredealer. Because tire technology continually evolves,visit the RMA web site at www.rma.org for currentinformation.

The Right Tire for theVehicle

When tires need to be replaced, do not guess whattire is right for the vehicle. For the answer, refer tothe vehicle tire placard and/or certification label,usually located on the vehicle door edge, door post,glove box or fuel door. Also, check the vehicleowner’s manual for any additional tire replacementrecommendations. The vehicle tire placard identifiesthe size of the tires, including the spare, that wereinstalled on the vehicle as original equipment (OE).The placard also specifies the recommended coldinflation pressures for the tires on the front/rearaxles and for the spare. The placard may includeseating capacity and combined weight of occupantsand cargo. If the vehicle does not have a vehicle tireplacard or certification label, consult the vehicleowner's manual, vehicle manufacturer, or tiremanufacturer. A tire dealer should also be familiarwith these requirements and is an excellentresource.

In addition, tires have very useful informationmolded into the sidewall including the tire brand,model, size, speed rating, maximum load, maximuminflation, and safety warning(s). See Chapter 1.

Tire, Size, Inflation and Load

Tire ReplacementsReplacement tires should be the same as the OE sizedesignation, or approved options, as recommendedby the vehicle or tire manufacturer. Never choose areplacement tire of a smaller tire size or with lessload-carrying capacity than the OE tire size at thespecified vehicle placard pressure. Under certaincircumstances, a vehicle manufacturer mayrecommend or permit a specific substitute tire size,inflation pressure, maximum speed, maximum load,etc. It is recommended that all four tires be of thesame size, speed rating, and construction (radial,non-radial). In some cases, the vehicle manufacturermay specifically advise against the application ofreplacement tires that are not the original size. Inother cases, the vehicle manufacturer may requiredifferent sized tires for either the front or rear axles.(Also see “Tire Mixing” on p. 41, and “Important

Chapter 3, Page 37

NOTEBefore replacing tires, ALWAYS refer to andfollow the vehicle manufacturer's tirereplacement recommendations and restrictions.

13 As defined by 49 CFR Part 571.139, Federal Motor Vehicle Safety Standard (FMVSS 139), light vehicles are motor vehicles with a gross vehicle weightrating (GVWR) of 10,000 lbs. or less. Tire sizes for light vehicles include all passenger car tires and light truck tire sizes (through Load Range E).


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Considerations” on p.45.) Always check and followthe recommendations in the vehicle owner'smanual.

Replacement tires must have:

• Inflation pressure capability equal to or greaterthan the operating inflation pressure specified onthe vehicle tire placard.- When determining the proper tire inflationpressure settings for substitute tires, neverexceed the maximum pressure listed on thesidewall of the tires.- Carefully note any differences betweenrecommendations for front and rear axlepositions regarding the tire size and/or inflationpressure.

• Load-carrying capacity must be equal to orgreater than the load-carrying capacity of the OEtire size at the specified vehicle placard pressure.

• Speed rating (such as “S,” “T,” “U,”, “H,” “V,” “Z,”etc.) must be equal to or greater than what isspecified by the vehicle manufacturer if the speedcapability of the vehicle is to be maintained. (Alsosee “Tire Mixing” on p. 41, and “ImportantConsiderations” on p. 45.)

Tire Size Designation Differences BetweenPassenger and Light Truck Tires

Passenger Tires: P-Metric, European MetricLight Truck Tires: LT-Metric, LT High Flotation,European Commercial Metric and LT Numeric

These groups of tires have differences in their loadand inflation characteristics, including somedifferences in their load capacity if they are appliedto a passenger car versus a light truck. Vehiclehandling may be affected when passenger tires arereplaced with LT tires. Therefore, it is necessary tocarefully consider these differences whenconsidering a replacement tire that is not the sameas the OE size.

Light Truck Tire ReplacementIn addition to the considerations already stated, alsobe sure to take into account the following itemsrelative to light truck (LT) tire replacement.

• Tires should only be mounted on approved rimwidths (see "Tire Rim/Wheel Selection" on p. 42).If changing tire size, the rim/wheel must haveadequate load and inflation pressure capability.For rims/wheels not so identified or for serviceconditions exceeding the rated capacities, consultthe rim/wheel manufacturer to determine therim/wheel capabilities.

• Body and chassis clearance must be checked onthe vehicle's front and rear axles (see "Tire,Vehicle Clearance and Tire Diameter" on p. 43).

• Proper spacing between duals (minimum dualspacing) is necessary for optimum tireperformance. Consult tire or vehicle manufacturers'literature for recommendations. If chains are used, particular care must be taken to assure adequateclearance between loaded tires to avoid damagefrom chains. Allowable outside diameterdifferences between a tire and its dual mate is 1/4"for light truck tires.

• For tube type tires, be sure to use approvedtubes/flaps/valves for the replacement tire.When used in radial tires, radial tubes and radialflaps are required.


Chapter 3, Page 38

NOTEALWAYS check the vehicle manufacturer'srecommendations for the OE tire size, loadcapacity, inflation pressure, and speed ratinginformation before replacing a tire with adifferent size and construction. It is not alwayspossible to select the same tire size for areplacement tire. NEVER choose a smaller size orwith less load-carrying capacity than thespecified size on the vehicle tire placard.

NOTEBe sure to maintain any difference in inflationpressures for front and rear tires as indicated onthe vehicle’s tire placard.

Replacing OE Passenger Tires with LT TiresSome vehicles, such as sport utility vehicles, vans,and pick-up trucks, may have passenger tiresinstalled as original equipment. As previouslystated, it is preferred that replacement tires shouldbe the same OE size designation, or approvedoptions, as recommended by the vehicle or tiremanufacturer. However, in some cases, the OEpassenger tires on these types of vehicles can bereplaced with light truck tires, which are tiresmarked with an "LT" designation on the sidewall. LTtires for light vehicles, which are vehicles with aGross Vehicle Weight Rating (“GVWR”) of 10,000 lbs.or less, include load ranges "B," "C," "D" and "E."

Replacing passenger car tires with light truck tireswill require a significant inflation pressureadjustment in order to carry the same load as theoriginal equipment size. Passenger tire load-carrying capacity must be reduced by dividing by1.10 for light truck applications. For example:P235/75R15 which has a maximum load capacity forpassenger vehicle application = 2028 lbs. For a lighttruck application, using the formula, the maximumload capacity would be 2028 / 1.10 = 1844 lbs. Inaddition to the important considerations listedabove, be sure to consult with vehicle manufacturer,tire manufacturer, and/or a professional tire dealerfor the appropriate replacement size, adjusted

inflation pressure, and load rating for the vehicle.See “Important Considerations, Inflation Pressure: OEvs. Replacement” on p. 45.

Chapter 3, Page 39

NOTEUnless otherwise specified by the vehiclemanufacturer, it is not recommended to replaceOE LT-metric, LT High Flotation, or LT Numerictires with P-metric (e.g. P205/60R15) orEuropean metric tires (e.g. 205/60R15).

NOTEWhen replacing OE passenger tires with LT tires,check with the vehicle manufacturer to be surethe rim/wheel is appropriate for the requiredhigher inflation pressures. Check rim widths andrim load/inflation capacity; check body andchassis clearance. Purchase of new rims/wheelsmay be required.


There is a danger of serious injury or death if atire of one bead diameter is installed on a rim orwheel of a different rim diameter.

ALWAYS replace a tire with another tire ofexactly the same bead diameter as the diameterof the rim on which it will be mounted.

For example: a 16” tire goes on a 16” rim.NEVER mount a 16” tire on a 16.5” rim. A 16.5”tire ONLY goes on a 16.5” rim. NEVER mount a16.5” tire on a 16” rim.

While it is possible to pass a 16” diameter tireover the lip or flange of a 16.5” size diameter rim,it CANNOT be inflated enough to position itselfagainst the rim flange. If an attempt is made toseat the tire bead by inflating, the tire will breakwith explosive force and could cause seriousinjury or death.

Rims of different diameters and tapers CANNOTbe interchanged. The following diagramillustrates the difference between rims of twodifferent tapers and diameters.

The following diagram shows how beads of a16” tire will not seat on a 16.5” rim. The beadsCANNOT be forced out against the rim flanges byusing more air pressure because this will breakthe beads and the tire will explode with forcesufficient to cause serious injury or death.

Self-Supporting Runflat TireReplacement

Runflat tires14 have specific servicing requirements,such as product-specific puncture repair ordemounting/mounting procedures, which vary byvehicle and tire manufacturers. Consult with themanufacturers for details. A functioning tirepressure monitoring system (TPMS) must be usedwith runflat tires.

Four Tire Runflat ReplacementWhen replacing tires normally (i.e. wear out), it isrecommended and preferred that all four runflattires are replaced at the same time with four runflattires in order to maintain runflat tires' mobility,TPMS capability, and vehicle handling, stability andperformance. Check owner’s manual for specificrecommendations. It is important to ensure that theTPMS on the vehicle functions with the replacementrunflat tires.

Emergency, Temporary Single Conventional TireReplacementDepending on the circumstances, some runflat tiresmust be replaced after they have experienced low-or zero-inflation pressure. Never mix runflat tireswith conventional tires (tires that do not have runflattechnology) unless in an emergency situation on alimited, temporary basis. The conventional tireshould be replaced with a runflat tire as soon aspossible. It is not recommended to mix incompatiblerunflat technologies/products. If a conventional tireis used on a temporary basis, it is important to notethat vehicle handling characteristics may beaffected. Also it is recommended that theconventional replacement tire is of the same size,inflation pressure, load-carrying capacity and speedrating noted on the vehicle tire placard.

Runflat Replacement with Four Conventional TiresIt is recommended and preferred to replace runflattires with runflat tires; however, a consumer maywish to replace the OE runflat tires with non-runflat,conventional tires. Consult with the vehicle and tiremanufacturers before replacing runflat tires withconventional tires to identify any vehicle operationrestrictions. If the conventional tire option is chosen,then application restrictions apply, including but notlimited to the following:

• Loss of runflat capability

• Emergency mobility is negated (to maintainmobility, the consumer will need to acquireadditional equipment, such as a spare tire, newrim/wheel assembly, hand jack, etc.)

• Vehicle TPMS visual displays, audible alarms, andlogic designed for runflat operation may beaffected

• Vehicle handling, stability and performance canbe affected

• Vehicle owner's manual reference regarding OErunflat tire fitment may no longer apply

As standard practice, any replacement tires shouldbe of the same size, inflation pressure, load-carryingcapacity and speed rating as noted on the vehicletire placard.

Replacing Conventional Tires with Runflat TiresDepending on the specific tire, vehicle, wheel, TPMS,and other factors, runflat tires may be acceptablereplacements for conventional tires. However, avehicle or tire manufacturer may advise against theapplication of certain runflat tires to certain vehiclesthat were not originally equipped with runflat tires.Therefore, the vehicle and tire manufacturers mustbe consulted on their tire replacementrecommendations for specific vehicles and runflattires.

If conventional tires are to be replaced by runflattires, follow the same tire replacementrecommendations established for conventional tiresthat include selecting the proper tire size(s) andmeeting inflation pressure capacity, load-carryingcapacity and speed rating requirements. Refer to thevehicle and tire manufacturers' tire replacementrecommendations and the vehicle tire placard,certification label, and/or owner's manual.

In addition, note the following recommendations:

• The vehicle must have an operational TPMS. Ifnot originally equipped with a TPMS, a systemmust be retro-fit to the vehicle.

• Do not mix tires with incompatible runflat


Chapter 3, Page 40

14 Refer to RMA Tire Information Service Bulletin, Vol. 47, “General Information on Self-Supporting Runflat Tires.”

technologies on a vehicle (for example, all tiresshould be the same type of self-supportingrunflat).

• The wheels must be the recommended size/rimcontour, such as extended hump (example: EH2and EH2+) marked rims and must be compatiblewith the runflat tires and any TPMS sensors.

• The Inflation pressure recommendations forrunflat tires are the same as those forconventional tires that have the same size code,load index and speed rating.

Never mix runflat tires with conventional tires unlessin an emergency situation on a limited, temporarybasis. See Emergency, Temporary SingleConventional Tire Replacement above.

Tire Mixing

• It is recommended that all four tires be of thesame size, load index, speed rating, andconstruction (radial, non-radial). In some casesthe vehicle manufacturer may require differentsized tires for either the front or rear axles. NEVERmix P-Metric or European Metric passenger tireswith light truck (LT) sized tires on the samevehicle.

• Match tire size designations in pairs on an axle,except for temporary use of a spare tire.

• If two radial tires and two non-radial tires areused on a vehicle, put radials on the rear axle. Ifradial and non-radial tires are used on a vehicleequipped with dual rear tires, the radial tires maybe used on either axle.

• Speed rated tire - If the vehicle tire placard and/orowner's manual specifies speed rated tires, thereplacement tires must have the same or higherspeed rating to maintain vehicle speed capability.Tire speed ratings do not imply that vehicles canbe safely driven at the maximum speed for whichthe tire is rated, particularly under adverse roadand weather conditions, or if the vehicle hasunusual characteristics. Never operate a vehicle inan unsafe or unlawful manner.

If replacement tires have lower speed capabilitythan specified by the vehicle manufacturer, thevehicle's speed must be restricted to that of thereplacement tire. Also, vehicle handling could beaffected. Consult vehicle manufacturer or tiremanufacturer for recommendations.

• Four-wheel drive (4WD) and all-wheel drive(AWD) vehicles - If no instructions for tire mixingappear in the vehicle owner's manual, followthese guidelines:

- DO NOT mix tire sizes. All four tires must bemarked with the same tire size, unlessotherwise specified by the vehiclemanufacturer. This also applies to winter/snowtires.

- DO NOT mix radial and non-radial tires. All fourmust be either radial or non-radial.

- DO NOT mix tread pattern types such as all-terrain and all-season.

• Winter/snow tires15 - It is always preferable toapply winter/snow tires to all wheel positions,including duals, to maintain vehicle mobility andcontrol.

- If winter/snow tires are applied to the frontaxle of a vehicle, winter/snow tires must alsobe installed on the rear axle. DO NOT applywinter/snow tires only to the front axle. Thisapplies to all passenger and light truck vehiclesincluding front-wheel-drive, 4WD, and AWDvehicles.

- If winter/snow tires are installed on the rearaxle of any vehicle, it is recommended (but notrequired) that they also be installed on the frontaxle.

• Studded winter/snow tires - Studdedwinter/snow tires have higher traction qualitiesunder most winter weather conditions.

- If studded winter/snow tires are installed onthe front axle of any vehicle, studdedwinter/snow tires must also be installed on therear axle. DO NOT apply studded winter/snowtires only to the front axle.

- If studded winter/snow tires are installed onthe rear axle of any vehicle, it is strongly

Chapter 3, Page 41


15 Also see RMA Tire Information Service Bulletin, Vol. 42, “Application of Winter/Snow Tires and Studded Winter/Snow Tires.”

recommended that they should also beinstalled on the front axle. Only if studdedwinter/snow tires are installed on all wheelpositions of a vehicle will optimum handlingcharacteristics be achieved.

Some states prohibit the use of studded tires andmany states have seasonal limitations on their use.Before installing, check with state and localregulations.

Replacing Less Than FourTires

When replacing tires on a vehicle, it isrecommended and preferred that all four tires bereplaced at the same time for continued optimalvehicle performance. However, for those caseswhere this is not feasible, below are some generalguidelines to consider when replacing less than fourtires for a light vehicle, whether it is one or two tires.(Also see “Tire Mixing” on p. 41.) If the vehiclemanufacturer has alternate recommendations,always follow their recommendations.

Replacing Two (2) Tires - When a pair ofreplacement tires is selected in the same size andconstruction as those on the vehicle, the two newertires should be installed on the rear axle. Generally,new tires with deeper tread will provide better gripand evacuate water more effectively, which isimportant as a driver approaches hydroplaningsituations. Placing greater traction on the rear axleon wet surfaces is necessary to prevent a possibleoversteer condition and loss of vehicle stability.

Replacing One (1) Tire - Replacing a single tire on avehicle can have an adverse effect on suspensionsystems, gear ratios, transmission, and tiretreadwear. If single tire replacement is unavoidable,it is recommended that the single new tire be pairedwith the tire that has the deepest tread and both beplaced on the rear axle. Placing greater traction onthe rear axle on wet surfaces is necessary to preventa possible oversteer condition and loss of vehiclestability.

Tire Rim/Wheel Selection

Tires should only be mounted on approved rimwidths (for more information, refer to tiremanufacturer product literature for rim widthspecifications).Figures 10 and 11 illustrate examplesof series profile and rim width, respectively.


Chapter 3, Page 42

NOTEIn some cases, the vehicle manufacturer mayspecifically advise against replacing less than allfour tires. Always check and follow therecommendations in the vehicle owner’smanual. For 4WD and AWD vehicles, even smalldifferences in outside diameter may cause drive-train damage or mechanical malfunction.

Installing winter/snow tires (studded orunstudded) only on the front axle may cause thevehicle to experience adverse handlingcharacteristics. This may result in an accident,which could cause serious injury or death.

FFiigguurree 1111:: 66 iinncchh RRiimm WWiiddtthh EExxaammppllee

FFiigguurree 1100:: SSeerriieess PPrrooffiillee EExxaammppllee

Series (Profile)Series tires use numbers“75,” “80,” “70” to indicatetire’s profile or height to width ratio. For example, “75 Series” means that tire is approximately 75% as high as it is wide.

Height isapproximately75% of width

Width

• Always check to be certain that the diameterdesignation for both tire and rim are the same.For example, a P235/75R16 tire must be mountedon a 16-inch rim (see the rim WARNING on p. 39).

• If replacement tires or rims/wheels are of adifferent size from the OE, be sure that theoutside circumference of all four tires is withinthe accepted tolerance of the vehiclemanufacturer.

• Some rims/wheels may not allow correct beadseating unless the OE tire is used. Consult vehiclemanufacturer.

• Never exceed the maximum pressure and/or loadcapacity of the rim/wheel.

Tire, Vehicle Clearance andTire Diameter

Acceptable load index, load capacity, and/or overalldiameter do not imply acceptable vehicle clearance.Body and chassis clearance must be checked on thevehicle's front and rear axles. If replacement tires orrims are of a different size from the originalequipment, all four (4) wheel positions must bechecked for proper clearance in the fender well,around brake components, shock towers, othersuspension components, etc. These wheel positionsmust be checked for full suspension jounce andrebound. Steering tires must be checked in full leftand right turns. Also, check to be sure that theoutside circumference of all four tires is within theaccepted tolerance of the vehicle manufacturer.

Differences in overall diameter may affect vehiclehandling and stability as well as the following:speedometer, odometer, ABS, tire pressuremonitoring system, 4WD / AWD / traction control,and other electronic systems. To maintain accuracy,resetting or recalibration of these systems may benecessary. Compare the nominal dimensions on thevehicle tire placard and candidate replacementsizes. Check the vehicle manufacturer'srecommendations.

Plus Sizing

Plus sizing for light vehicles in the after-market isprimarily based on the following tire/wheelcharacteristics:

1) Maintain overall tire diameter of the OE tires 2) Increase the tire section width (contact

patch/footprint becomes shorter and wider)3) Decrease the series profile (aspect ratio or

section height)4) Increase the rim/wheel diameter

Chapter 3, Page 43


High pressure “T” type temporary spare tiresshould not be used with any other rims/wheels,nor should standard tires, snow tires, wheelcovers, or trim rings be used with the highpressure “T” type temporary spare rim/wheel. A“T” type temporary spare tire and wheel assemblyshould never be used on a vehicle with which it isnot compatible, nor should more than one suchtire ever be placed on any vehicle at a given time.Standard tires or snow tires should NOT bemounted on a high pressure compact sparewheel.

Mismatch of the tire and/or rim parts may causethe assembly to burst with explosive force,sufficient to cause serious physical injury ordeath.

NOTEAlways use approved tire and rim combinationsfor diameters and contours.16

NOTEBefore replacing tires, ALWAYS refer to andfollow the vehicle manufacturer's tirereplacement recommendations and restrictions.

16 This means approved tire and rim combinations that are established and approved by the appropriate industry standards organizations including the Tire& Rim Association, Inc., European Tyre and Rim Technical Organisation, Japan Automobile Tyre Manufacturers Association, Inc. or by the tire manufacturer.For more information on approved rim widths, refer to tire manufacturer product literature for rim width specifications.

Plus sizing is generally conveyed in terms of “Plus1,” “Plus 2,” “Plus 3,” etc. Examples of plus sizing areillustrated in Figure 12. If tire fitments other than theOE tire are desired, always consult vehicle and tiremanufacturers' recommendations and consider thefollowing:• Aspect Ratio: Additional consideration should be

made for substitute tires that are lower in aspectratio than the OE tire fitments. Lower aspect ratiotires typically aid performance and handling, butthey may provide a less comfortable ride. Highperformance, low aspect ratio tires may alsowear more quickly and produce more noiseduring operation. Low aspect ratio tires and their

rim/wheel assembly are more susceptible todamage from road hazards and pothole/curbimpact.

• Overall Diameter: Check to be sure that theoverall diameter of all four tires is within theaccepted tolerance of the vehicle manufacturer.

• Inflation Pressure: Check to see if it needs to beadjusted (see “Important Considerations” on p. 45).

• Load-Carrying Capacity: Must be equal to orhigher than the OE fitment.

• Speed Symbol/Category: Must be equal to orhigher than the OE fitment if the speed capabilityof the vehicle is to be maintained. See “ImportantConsiderations” on p. 45.


Chapter 3, Page 44

FFiigguurree 1122:: Plus Size Concepts - Hypothetical Examples

• Rim Width/Off-Set: Check OE/rim manufacturer'srecommendations.

• Rim/Wheel Selection: Never exceed themaximum pressure and/or load capacity of therim/wheel.

• Vehicle Clearances: Steering tires must bechecked in full left and right turns. All wheelpositions should be checked for proper clearancein fender wells, around brake components, shocktowers, and other suspension components.These wheel positions must be checked for fullsuspension jounce and rebound.

• Vehicle Modifications: Lift kits and other types ofsuspension alterations or use of tires notapproved by the vehicle or tire manufacturer canadversely affect vehicle handling and stability.

• State/Local Laws: Check to be sure that thefitment complies with any state/local regulations.

Important Considerations

Inflation Pressure: OE vs. Replacement - Fitment ofa new tire (other than the OE size) on the vehiclemay require a higher inflation pressure thanspecified on the vehicle tire placard to adequatelycarry the load. If so, the installer should inform theowner of the new required inflation pressure. Theinstaller should also place a sticker or decal next tothe vehicle tire placard showing the new tire sizeand inflation pressure requirements for futurereference. Never inflate a tire below therecommended pressure shown on the vehicle’s tireplacard.

Standard Load (SL) vs. Reinforced or Extra-Load (XL) Fitments - Some passenger tireshave extra load capabilities. Generally, these tireswill have “XL” or “Extra Load” or “Reinforced”molded on the sidewall of the tire. Special careshould be exercised when considering reinforced orextra load (“XL”) tires as substitutes for standardload (“SL”) tires. A reinforced or “XL” tire offershigher maximum load capacity than a “SL” tire of thesame size; however:

• “XL” tires require higher inflation pressure toattain the added load capacity. (See “InflationPressure” above.)

• For “XL” tires, an equal or greater load index isnot always an adequate indicator of a tire'ssuitability for the load capacity. As a result, themaximum load capacity and inflation pressure,which is also molded on the tire sidewall, must bereferenced.

Load Index• The load index is the number preceding the speed

symbol on a tire’s sidewall. For example, if the tireis labeled as P215/65R15 95H, then “95H” is the“service description” where “95” is the “loadindex.” For more detailed information, see page10 in Chapter 1.

• Tires with the same load index, regardless of thetire size, may carry the same load, but not always,and they may require different inflation pressures.In addition, some tire sizes are available in morethan one load index. The load index may not beused independently to determine replacement tireacceptibility for load capacity. An equal or greaterload index does not always correspond to equalor greater capacity at all inflation pressuresettings, particularly when comparing P-metricand Euro-metric passenger car tires. Refer to thetire manufacturer’s recommended inflationpressures for the tire selected (see “InflationPressure: OE vs. Replacement”).

Speed Rating• Speed rating of the tire must be equal to or

greater than what is specified by the vehicle tireplacard, or owner’s manual, if the speedcapability of the vehicle is to be maintained. Forexample, if the tire is labeled as P215/65R15 95H,then “95H” is the “service description” where “H”is the “speed symbol.”

• If replacement tires have lower speed capabilitythan specified by the vehicle manufacturer’srecommendations, the vehicle's speed must berestricted to that of the replacement tire. Also,vehicle handling could be affected. Consultvehicle or tire manufacturers.

• If the vehicle manufacturer’s recommendationsdo not call for speed rated tires, replacement tiresmay be speed rated if desired.

Chapter 3, Page 45


• If installing winter/snow tires and if the vehicleplacard specifies speed rated tires, winter/snowtires of equivalent or greater speed rating must befitted if the speed capability of the vehicle is to bemaintained. For cases where the winter/snowtires’ speed rating cannot match the OE tire, it isgenerally acceptable to apply a winter/snow tirewith a lower speed rating than the OE tire;however, the vehicle speed is to be restricted tothat of the replacement tire. Refer to the vehicleowner's manual for specific recommendationsand/or restrictions regarding winter/snow tires.

Passenger and Light Truck Used Tires1177



Not all tire damage that can lead to tire failure isoutwardly visible. For instance, improper repairs ordamage to a tire’s innerliner can only be observed byinspecting the inside of the tire, demounted from thewheel. A qualified tire service professional shouldinspect the internal and external condition of theused tires prior to application. In the case of a used

vehicle purchased by a consumer, the only way todetermine the condition of its tires is to have themdemounted by a tire service professional for thesame type of inspection.


Chapter 3, Page 46

17 Reference to RMA Tire Information Service Bulletin, Vol. 45, “Passenger and Light Truck Used Tires.”

Driving on damaged tires is dangerous. Adamaged tire can suddenly fail leading tosituations that may result in serious personalinjury or death. Tires should be regularlyinspected by a qualified tire serviceprofessional.

Chapter 4, Page 47

Recreational Vehicle Applications

CSPLT4-0811

CHAPTER 4 (IN A 4 CHAPTER SERIES)

RECREATIONAL VEHICLEAPPLICATIONS

Overview

This chapter contains additional guidelines to helpobtain the best performance from tires used on RVs.Use this chapter in conjunction with the otherchapters in this manual. Unless otherwise specified:1) the term “RV” applies to: motor homes; traveltrailers; 5th-wheel travel trailers; and, slide-incampers for pickup trucks, and 2) the term “RV tires”identifies all tires used on RV vehicles. Moreinformation about the specific vehicle and its tires iscontained in the owner's manual supplied by thevehicle manufacturer. Additional informationconcerning RV tires is available from the tiremanufacturer.18

The Recreational Vehicle Safety & EducationFoundation (RVSEF) has weighed over 25,000 motorhomes and travel trailers in conjunction with RVevents. Of the RVs checked by RVSEF, more than 57percent had loads that exceeded the capacity of oneor more tires on the vehicles. Most of the weightwas on the rear. In a separate survey conducted bya tire company, 4 out of 5 RVs had at least one underinflated tire, a third of which were significantlyunder inflated, and at risk of failure.

An under inflated tire cannot adequately carry theload placed upon it and will be subjected toexcessive stress, strain, and heat build-up which canlead to tire failure. Also the under inflated tire in adual pair can cause a weight transfer to the properlyinflated tire resulting in it being over loaded whichmay lead to tire failure. Often, these significantlyunder inflated tires were the inner tires of dual pairs,tires that are more difficult to see and service. Onaverage, RVs were over loaded by over 900 pounds,based on the RV manufacturer's specifications.

RV Tire and VehiclePlacards/Labels

In order to determine specifications for tire size, tireinflation pressure, and vehicle loading, it may benecessary to consult different placards/labelsdepending upon the vehicle type, model year, andmanufacturer. These placards/labels include thefollowing:

• Vehicle Certification Label• Vehicle Tire Placard• Motor Home Occupant and Cargo Carrying

Capacity Label• RV Trailer Cargo Carrying Capacity Label• Motor Home Supplemental Label• RV Trailer Supplemental Label• Load Carrying Capacity Modification Label

These placards/labels may be found in differentlocations depending upon the vehicle, including thefollowing:

Left Side: Driver's door edge, hinge pillar, or door-latch post

Right Side: Forward-most exterior passenger dooredge, hinge pillar, or door-latch post

Vehicle Interior: Posted on a surface near the driveror storage area

Vehicle Exterior: Posted on surface near the trailerhitch

18 Consumers can also find this information in the RMA booklet “RV Tire Care and Safety Guide.”

Chapter 4, Page 48


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The type of important tire and loading informationon the placards/labels includes the following:

1. Gross Vehicle Weight Rating (GVWR)2. Gross Axle Weight Rating (GAWR) for each axle3. Tire and wheel/rim sizes4. Recommended cold tire inflation pressures

Consult the vehicle owner's manual for additionaltire and loading information. Follow the vehicle tireplacard, certification label and owner's manual forrecommended vehicle load limits and tire inflationpressures.

When replacing RV tires, refer to the certificationlabel for the tire size(s) and load capacity (loadindex) recommended by the RV manufacturer. Ifreplacing with a tire size other than shown on thecertification label, consult the RV manufacturer ortire service professional for recommendations.Using the wrong tire size or load range (load index)can lead to tire failure.

Vehicle modifications such as lift kits and othersuspension alterations and/or use of tires notrecommended by the vehicle or tire manufacturercan adversely affect vehicle handling and stability.

Tires specifically designed for travel trailer use inhighway service have an "ST" (Special Trailer)molded on the tire sidewall (ST225/75R15 orST235/80R16). ST tires have different load capacitycharacteristics. Therefore, ST tires should not bereplaced with any other type tire.

RV Tire and Vehicle LoadLimits

To avoid overloading RV tires, maintain the properinflation pressure and never exceed the vehicle'sgross axle weight ratings (GAWR) or the GrossVehicle Weight Rating (GVWR) stated on thecertification label. The vehicle load must also bedistributed so that no individual axle, tire or dualassembly is over loaded.

The maximum load for each tire is molded on thetire sidewall (along with the maximum inflationpressure for that load). Never exceed the stated

maximum limits on the tire, rim or wheel assembly. The major components of an RV - the vehicle frame,brakes, axles, rims/wheels, tires, etc. - are designedto accommodate a particular weight. If these weightratings are exceeded, these parts may wear rapidlyor may fail prematurely in-service. The RVmanufacturer provides the weight ratings and loadspecifications printed on the vehicle tire placard orcertification label as follows:

• GGVVWWRR:: GGrroossss VVeehhiiccllee WWeeiigghhtt RRaattiinngg -- The weightrating established by the chassis manufacturer asthe maximum weight (including vehicle, cargo,liquids, passengers, etc.) the components of thechassis are designed to support.

• GGAAWWRR:: GGrroossss AAxxllee WWeeiigghhtt RRaattiinngg ((ffoorr eeaacchh aaxxllee)) -The maximum weight rating that the components(tires, rims/wheels, brakes, springs, and axle) ofeach axle are designed to support. This isdetermined by the lowest design capacity of anycomponent. In other words, if the wheels have thelowest design capacity of any component on thataxle, installing tires with a higher load capacitydoes not increase the GAWR. By regulation, thetire load rating times the number of tires on thataxle must equal or exceed the GAWR for that axle.

• GGCCWWRR:: GGrroossss CCoommbbiinneedd WWeeiigghhtt RRaattiinngg -- GCWRrepresents the maximum allowable total loadedweight rating of the vehicle and anyvehicle/trailer it is towing. GCWR minus GVWRrepresents the allowable weight for the towedvehicle.

• GGVVWW:: GGrroossss VVeehhiiccllee WWeeiigghhtt -- GVW is the actualweight of a fully loaded vehicle (including vehicle,cargo, liquids/fuels, passengers, tongue weight19,etc.). The GVW must not exceed the GVWR.

• GGAAWW:: GGrroossss AAxxllee WWeeiigghhtt -- GAW: Gross Axle WeightGAW is the actual weight of a fully loaded vehiclecarried by a single axle. Due to the many waysthat weight can be distributed within an RV, GAWcan often provide a false sense of security. Thetotal weight on an axle may be within the axle'srating, but the distribution of the load may beoverloaded on one side. The GAW must notexceed the GAWR.


Chapter 4, Page 49

19 "Tongue weight" is the downward weight exerted at the hitch or 5th wheel connection by a fully loaded towed trailer. The towing vehicle's tires - not thetowed trailer's tires - support this weight.

Proper RV Tire Inflation

The recommended inflation pressures for RV tiresare indicated on the vehicle tire placard,certification label, or in the owner's manual. Neverset tire inflation pressures below the recommendedinflation pressure found on the vehicle tire placard,certification label or owner's manual. Underinflation causes excessive heat build-up and internalstructural damage that may lead to a tire failure,even at a later date. Do not exceed the maximuminflation pressure shown on tire sidewall. Overinflated tires (over the maximum molded on the tiresidewall) are more likely to be cut, punctured ordamaged by sudden impact from hitting an obstacle,such as a pothole.

To maintain the correct pressure in RV tires, checkthe inflation pressure regularly with a dual-headpressure gauge that is calibrated up to 120 psi in atleast 2 psi increments. Even if it is difficult to checkthe inflation pressures of inside tires in dualfitments, it is imperative that these inflationpressures be checked and properly maintainedbecause the inside dual tires are subjected to moresevere operating conditions, such as:

• High heat exposure, due to close proximity tobrakes

• Lower air circulation to assist in cooling • Crowned road surfaces (which can cause inside

dual tires to support more of the load than theoutside dual tires)

PPrrooppeerr IInnffllaattiioonn iiss CCrriittiiccaall - Inflation pressureenables a tire to support the load and to control thevehicle, therefore proper inflation is critical. With theright amount of inflation pressure, the vehicle andthe tires will achieve their optimum performance. Inaddition to tire safety, this means your tires willwear longer and improve vehicle fuel consumption.

It is impossible to determine whether radial tires areproperly inflated just by looking at them. You mustuse a tire gauge to properly check the inflationpressure. Motorists should have their own gaugeand keep it in the vehicle.

WWhheenn TToo CChheecckk IInnffllaattiioonn PPrreessssuurree - Check inflationpressure when tires are cold, that is, when thevehicle has been parked for at least 3 hours or hasbeen driven less than one mile at moderate speed.The inflation pressure in all tires, including the sparetire and inside duals, should be checked with anaccurate tire gauge at least once per month, beforeeach trip and each morning you drive during a trip.This includes vehicles equipped with a Tire PressureMonitoring System (TPMS). Maintaining properinflation pressure maximizes fuel economy andoptimizes overall tire performance.

Never “bleed” or reduce inflation pressure whentires are hot from driving, as it is normal forpressures to increase above recommended coldpressures. If a hot tire pressure reading is at orbelow recommended cold inflation pressure it maybe dangerously under inflated.

Chapter 4, Page 50


Under inflation and/or over loading of a tire causes excessive heat build-up and internal structural damage.This may cause a tire failure, including tread/belt separtion, even at a later date, which can lead to anaccident and serious personal injury or death.

Over loading an RV can have other serious safety consequences such as suspension or wheel failure,increased braking distance or brake failure (particularly on steep grades), and adverse vehiclehandling/stability.

Consult the vehicle tire placard, certification label and owner’s manual for the recommended vehicle loadlimits and tire inflation pressures.

In this case, immediately determine the causeand/or have the tire checked by a tire serviceprofessional.

A passenger or light truck tire used on an RV maylose 1 to 2 psi inflation pressure per month undernormal conditions and 1 to 2 psi for every 10degrees F temperature drop. Truck/bus tires maylose more due to their higher operating pressures. Ifan RV tire continually loses more than 2 psi permonth (4 psi for truck/bus tires), have it checked bya qualified tire service professional.

Significant changes in altitude or temperature atwhich a vehicle will regularly operate, will result inchanges in inflation pressure and will require aninflation pressure check and adjustment.

Valves20 - Metal valve caps with rubber seals arerecommended for RV applications due to generallyhigher operating pressures. The metal cap with arubber gasket provides a seal that a plastic valve capmay not provide.

Bolt-in (clamp-in) metal valve stems arerecommended for RV applications. They MUST beused when valve extensions are installed because theextra weight of the extension or hose can distortrubber stems and ultimately cause loss of inflation.

When dual tires are mounted on a vehicle, theyshould always be installed with the valve stems 180degrees apart (for example, if one valve is at the 6 o'clock position then the other should be at the 12o'clock position).

It may be necessary to install an extension hose witha bolt-in (clamp-in) metal valve stem to checkinflation on an inside dual tire in some applications.It is recommended to use extension hoses withstainless steel reinforcement and external braidingas protection. The ends of the hoses should besecurely attached to the wheels so that they cannotcome loose while driving. If the holes in the wheelsare too small or in the wrong place to be able tocheck inflation pressure on the inside tires, thissituation must be corrected before travel.

DDeetteerrmmiinniinngg PPrrooppeerr IInnffllaattiioonn PPrreessssuurree - With actualweights of the loaded RV acquired by weighing, it ispossible to compare them against the GAWR,GVWR, and tire capacities posted on the vehicle tireplacard or certification label. These actual weightsare also what should be used to determine anyincrease in inflation pressure for the tires, ifrequired. (See “How to Determine an RV's ActualWeight” on p. 53.)

Inflation pressure recommendations may also bedetermined based on the tire manufacturer'sspecifications, which define the amount of inflationpressure necessary to carry a given load. Theseinflation pressures may differ from those found onthe vehicle tire placard or certification label.

However, never use inflation pressure lower thanspecified by the vehicle tire placard, certificationlabel or owner’s manual. Nor should inflationpressure exceed the maximum pressure molded onthe tire sidewall.

Load and cold inflation pressure imposed on arim/wheel must not exceed the rim/wheelmanufacturer's recommendation, even though thetire may be marked for a higher load and inflation.Matching radial tires with rim/wheels must be donewith care. Older rims/wheels may not be approvedfor use with radial tires. Consult the RV or therim/wheel manufacturer for acceptablerims/wheels for a specific radial tire.


Chapter 4, Page 51

NOTEInstall a new valve assembly whenever a tire isreplaced. Rubber valve stems must always bereplaced when tires are replaced. In someinstances, tire/wheel assemblies may beequipped with a Tire Pressure Monitoring System(TPMS) sensor that is attached to or is part of thevalve assembly. When new tires are installed, it isrecommended to also replace all componentsthat are included in the TPMS valve replacementkit.

20 Refer to RMA Tire Information Service Bulletin, Vol. 40, “Tubeless Type Valves for Passenger and Light Truck Tires Including Tubeless Snap-In Tire ValveInstallation Procedure .”

Proper RV Tire and VehicleLoading

Tires used on RVs are typically subjected to agreater variety of loading conditions, often at ornear maximum loads, than automobile, light truckand truck applications.

Many RVs end up over loaded simply becausepeople put too many things in them. There is oftenno quick way to determine the weight of the itemsloaded, so there is a temptation to keep loadinguntil most of the available space is filled. Mostpeople tend to load by volume when weight is farmore important. Unfortunately, these circumstanceswill tend to exceed the load-carrying capacity of thetires or axles long before everything is on board.The only way to determine if the vehicle is overloaded is to have it weighed. See “How to Determinean RV’s Actual Weight on page 53.

It is also possible to be within the overall vehicle'sweight rating (Gross Vehicle Weight Rating orGVWR), yet still have over loaded axle ends or tires.That occurs because the load is not distributedevenly. Proper weight distribution may be difficult todetermine when loading a vehicle. The vehicle loadcan be unevenly distributed from front to rear orside-to-side. Uneven loading may cause the load tobe within an axle or tire's load-carrying capacity onone end of an axle, and over capacity on the other.Some types of load-leveling systems compensatefor uneven weight distribution, making it more

difficult to notice. Properly weighing the vehicle isthe only way to be sure.

The most critical point about weighing a vehicle isthat it must be weighed fully loaded (includingeverything that will be on board while traveling).That means the vehicle must be weighed withpassengers, supplies, food, water, fuel, oil, toweditems, bicycles, clothing, propane, etc. Note thatwater, fuel, and propane can easily exceed 750 lbs.

The Gross Axle Weight Rating (GAWR) or the GrossVehicle Weight Rating (GVWR) must never beexceeded. If any tire's maximum load capacity is notadequate to support the actual weight on that tireposition, there are two choices:

1) Lighten the load2) Install tires with a higher load-carrying capacity

If it is decided to install a tire size other than thatoriginally provided on the vehicle, care must betaken to ensure adequate load-carrying capacityand compatibility between the tire and rim. Alwayssupply a detailed weight slip for the vehicle, listingindividual wheel position load information, to a tireservice professional before proceeding. This is theonly way a tire service professional can determinewhich tire size has adequate load capacity and iscapable of proper inflation pressure. If the vehiclehas dual rear tires, installing a tire size other thanthe original size will require proper matching andspacing of the dual tire assembly. If chains are used,

Chapter 4, Page 52


Under inflation and/or over loading of a tire causes excessive heat build-up and internal structural damage.This may cause a tire failure, including tread/belt separtion, even at a later date, which can lead to anaccident and serious personal injury or death.

Over loading an RV can have other serious safety consequences such as suspension or wheel failure,increased braking distance or brake failure (particularly on steep grades), and adverse vehiclehandling/stability.

Consult the vehicle tire placard, certification label and owner’s manual for the recommended vehicle loadlimits and tire inflation pressures.

particular care must be taken to assure adequateclearance between loaded tires to avoid damagefrom chains. Consult a tire service professional forproper application.

How to Determine an RV’sActual Weight

The only sure way to determine actual weights is toweigh the fully loaded RV, wheel position by wheelposition and axle by axle, on level commercialscales. Individual wheel position weights are themost critical for accurate load determination.Certified public scales may be found at moving andstorage lots, farm suppliers with grain elevators,gravel pits, recycling companies, and commercialtruck stops. (Consult telephone book under “scales”or "weighing.") Allow adequate time since the entireprocess can take up to 30 minutes. There may be asmall fee for each weight taken, but the expense is aworthwhile investment towards the safe andeconomical operation of the vehicle.

For the weighing of the RV to be meaningful, it mustbe weighed fully loaded including: passengers, food,clothing, fuel, water, propane, supplies, etc. Anytowed vehicle (car/pickup, boat, or trailer) or anyitem loaded on brackets on the back of the RV, suchas bicycles, motorcycles, storage units, etc., shouldalso be included in the weighing.

PPOORRTTAABBLLEE WWHHEEEELL PPOOSSIITTIIOONN SSCCAALLEESSThe most effective method of determining wheelposition weights is to use portable scales designedfor individual wheel position measurement. Place ascale at each wheel position and record the load.

FFIIXXEEDD SSCCAALLEESS• Platform - long enough to weigh the completevehicle. Follow the steps on pages 55 to 57 for yourparticular vehicle to deterime individual positionloads.

• Segmented Platform - provides individual axleweights and total vehicle weights simultaneouslywhen the vehicle is positioned properly. Thesescales provide an easier method to determineindividual position loads.

• Single Axle Platform - This scale weighs one axleat a time (all tires on the same axle). These scalesprovide an additional method to determineindividual position loads.

Regardless of the method used, the RV must remainas level as possible, even if an axle or side is notphysically on the scale. There must be enough spaceon the side of the scale to accommodate the RVbeing partially off the scale.

If there is a difference in the weights on one side ofthe vehicle compared to weights on the other side,suspension components (tires, wheels, brakes,springs, etc.) on the heavier side could beoverloaded, even if the total axle load is within theGAWR.

Redistributing the load is essential to avoidcomponent failure, as well as to improve thehandling characteristics of the vehicle.

The actual or calculated weights can be comparedwith the GAWR, GVWR and tire capacities. The


Chapter 4, Page 53

NOTEInstalling tires with a higher load-carryingcapacity does not affect the load capacity of othercomponents (i.e. rims/wheels, axles, shocks,bearings, etc.). Rims may not be rated towithstand the load or higher inflation pressuresnecessary to support the load. If the load cannotbe adequately reduced, refer to the RVmanufacturer recommendations.

NOTEIt is not uncommon for an axle weight to bewithin the load limits of the axle, but improperlydistributed side-to-side, causing an over loadcondition on one of its wheel positions.Therefore, side-to-side weighing should also bedone.

weights also help determine the proper inflationpressure for the tires.

HHOOWW TTOO WWEEIIGGHH AA TTRRAAVVEELL TTRRAAIILLEERR

1. Weigh the travel trailer in its entirety whiledetached from the towing vehicle. The overallweight must be less than or equal to the GVWR forsafe operation. If the overall weight is greater thanthe GVWR, contents must be removed until GVWRlimitations are achieved.

2. Weigh the travel trailer while attached to thetowing vehicle. The towing vehicle should not be onthe scale. The result is the weight exerted on all ofthe trailer tires. Subtract this weight from the overallweight in Step 1(above) to determine "tongue"weight.

3. With the trailer still attached to the towing vehicle,each wheel position should be weighed separatelyto be sure each tire is not over loaded. If an overload condition exists on any wheel position, trailercontents must be redistributed or removed.

4. The individual wheel positions (particularly therear positions) on the towing vehicle should also beweighed while the trailer remains attached. This isespecially important on 5th-wheel applications. If anover load condition exists on the towing vehicle,trailer contents must be redistributed or removedand Steps 2 through 4 must be repeated.

Refer to the diagrams on p. 55 to 57 to record yourresults.

RV Tire InspectionGuidelines

In addition to maintaining inflation, regularlyinspect the tires' tread and sidewalls for irregulartread wear, cracking, scrapes, bulges, cuts, snags,foreign objects or other damage resulting from use.It is recommended that RV tires, including the spare,be periodically inspected by a tire serviceprofessional, including an inspection before everytravel season and during routine RV maintenanceintervals like oil changes and tire rotations.

Remove any stones, glass, foreign objects, etc.embedded in the tread to prevent damage. Evenminor damage can lead to further injury andeventual tire failure. Also, it is a good practice tocheck between dual tire/wheel assemblies forforeign objects, like large rocks, that may havebecome lodged between the tires, especially afteroff-road service.

Tires with excessive cracking on the tread orsidewall(s) should be removed from service. This istypically caused by under inflation, over loading,improper storage, and/or improper long-termparking. RV tires should be checked for thiscondition and any other damage before every trip.

For more information regarding tire inspectionguidelines and tire damage, see Chapter 2, “Tire Careand Service.”

Replace tires when worn to 2/32” (1.6 mm) depthremaining anywhere on the tread face. For vehicleswith a GVWR in excess of 10,000 pounds (4,536 kg),federal regulations state that tires on the front axleshould be removed when worn to 4/32” (3.2 mm)tread depth.21

Severe Service Operation

RV tires will wear out faster when subjected to highspeeds and high loads as well as hard cornering,rapid starts, sudden stops, and driving off-road or onsurfaces that are in poor condition. Rocks, holes orother objects can damage tires and cause wheelmisalignment. When driving on such surfaces, drivecarefully and slowly. Before driving on paved roadsat highway speeds, examine the tires for anydamage such as cuts or penetrations.

21 Refer to Code of Federal Regulations: 49 CFR 570.62 and 49 CFR 393.75(b)

Chapter 4, Page 54




Chapter 4, Page 55

Weighing an RV or Travel Trailer

Depending on the type of vehicle, use the Illustrations on p. 55, 56 or 57 to assist in weighing. For additionalassistance or information, consult with an RV or tire service professional.

Weighing a Single Axle Recreational Vehicle

RRVV:: TToo OObbttaaiinn AAxxllee aanndd GGrroossss VVeehhiiccllee WWeeiigghhttss

NOTEMaximum tire load capacity can only beachieved utilizing the maximum inflationpressure molded on the sidewall of the tire.

Note #1: From the tire manufacturer’s load and inflation tables or the sidewall of the tires mounted on the vehicle.Note #2: If vehicle has duals, read dual capacity from tire and multiply by two (2) to obtain dual assembly load carrying capacity.

The vehicle weight at each particular wheelposition must not exceed the maximum tire loadcapacity. Over loading the tire/wheel assemblymay lead to tire or wheel failure, which mayresult in an accident, serious personal injury ordeath.

RRVV:: TToo OObbttaaiinn IInnddiivviidduuaall WWhheeeell PPoossiittiioonn WWeeiigghhttss

Chapter 4, Page 56

Weighing a Pulling Vehicle and Travel Trailer

Weighing a Tandem Axle Recreational Vehicle

RRVV:: TToo OObbttaaiinn IInnddiivviidduuaall AAxxllee aanndd GGrroossss VVeehhiiccllee WWeeiigghhttss


Note #1: From the tire manufacturer’s load and inflation tables or the sidewall of the tires mounted on the vehicle.Note #2: If vehicle has duals, read dual capacity from tire tire and multiply by 2 (two) to obtain dual assembly load carrying capacity.

PPuulllliinngg VVeehhiiccllee:: TToo OObbttaaiinn IInnddiivviidduuaall AAxxllee aanndd GGrroossss VVeehhiiccllee WWeeiigghhttss


Chapter 4, Page 57

Note #1: From the tire manufacturer’s load and inflation tables or the sidewall of the tires mounted on the vehicle.Note #2: If vehicle has duals, read dual capacity from tire and multiply by two (2) to obtain dual assembly load carrying capacity.

TToo OObbttaaiinn IInnddiivviidduuaall WWhheeeell PPoossiittiioonn WWeeiigghhttss

TTrraavveell TTrraaiilleerr:: TToo OObbttaaiinn IInnddiivviidduuaall AAxxllee aanndd GGrroossss VVeehhiiccllee WWeeiigghhttss

TToo OObbttaaiinn IInnddiivviidduuaall WWhheeeell PPoossiittiioonn WWeeiigghhttss

Weighing a Pulling Vehicle and Travel Trailer (continued)

Sudden Ride Disturbance/Vibration

If the vehicle experiences a sudden vibration or ridedisturbance and/or there is a possibility the tiresand/or vehicle have been damaged, graduallyreduce speed. Do not abruptly brake or turn. Drivewith caution until you can safely pull off the road.Stop and inspect the tire. If the tire is under inflatedor damaged, deflate and replace it with the sparetire. If a cause cannot be detected, the vehicle shouldbe towed to the nearest vehicle or tire dealer for aninspection.

Tire Rotation

Rotating tires will help even out the amount of wearon each tire and extend the serviceability of theentire set. Most RVs have a matching full-size tire as its spare. It is important that the full-size spare isincluded in the RVs' tire rotation. See vehicleowner's manual for rotation recommendations. Iftires exhibit uneven wear, check for and correct, ifpossible, any misalignment, imbalance, or othermechanical problems before rotation. When tires arerotated on an RV, the inflation pressures may need tobe adjusted for the tires' new positions inaccordance with the actual load on that wheelposition. Under or over inflated tires may result inpoor vehicle handling, uneven treadwear, increasedfuel consumption and tire failure. Note: Lug nutsshould be properly torqued anytime a tire/rim/wheelassembly is re-installed on the vehicle.

RV Tire Service Life

Tires used on RVs are typically subjected to a greatervariety of service conditions, often at or nearmaximum loads, than automobile, light truck andtruck applications. It is important to have the RV andits tires in good operating condition.

Even though RV users often put no more than a fewthousand miles on their tires a year, RV tires mayneed to be replaced because of service conditionslong before the tread is worn out. To determine if RVtires, including the spare, should remain in service, itis recommended that they be periodically inspectedby a tire service professional, including aninspection before every travel season and duringroutine RV maintenance intervals like oil changesand tire rotations. The service life of tires includestheir overall condition and vehicle usage factors, notjust tread wear. All of these factors should be takeninto account when considering tire replacement. See“RV Tire Inspection Guidelines” on page 54.

Follow vehicle and tire manufacturers’ specificrecommendations, if any, regarding tire service lifeand replacement. In order to determine the age ofthe tire, look for the last four digits of the DOT tireidentification number (see Chapter 1, "Basic TireInformation" for details). For example, a tire with aDOT tire identification number ending with the last 4digits of 0309 indicates it was manufactured the 3rdweek of 2009.

RV tires that have been permanently removed fromservice should be rendered unserviceable anddestroyed so no one else can use them.

Tire Service Life is Not Determined by

Chronological Age - Tires are composed ofvarious materials, including rubber, havingperformance properties essential to the properfunctioning of the tire. These component propertiesevolve over a combination of time, service andstorage conditions. For each individual tire, thischange is affected by many elements such astemperature, storage conditions, and conditions ofuse (e.g., load, speed, inflation pressure, impacts

Chapter 4, Page 58



NOTESome RVs may have specific tire rotationrecommendations and/or restrictions. Seevehicle owner's manual.

and road hazard injury) to which a tire is subjectedthroughout its life. Since service and storageconditions vary widely, accurately predicting theservice life of any specific tire based on calendar ageis not possible. RMA is not aware of scientific ortechnical data that establishes or identifies a specificminimum or maximum service life for passengerand light truck tires. However, in some cases a tireor vehicle manufacturer may make a specific tirereplacement recommendation regarding itsproducts. If so, the consumer should consult themanufacturer with any questions with regard tofollowing the recommendation. Further, any suchrecommendation should not be considered aminimum service life for the tire.

Proper Tire Repair

Tires driven even a short distance while underinflated may be damaged beyond repair. Running atire under inflated is like running the vehicle'sengine without enough oil or coolant. It may seemto work fine for a time, but serious permanentdamage has occurred. Adding oil or coolant won'trepair engine damage, and adding inflation pressurewon't fix tire damage. The tire will remain seriouslydamaged and can still fail, even after inflationpressure is corrected.

If a tire is losing inflation pressure, a tire serviceprofessional should check the tire surface and thevalve for the source of the leak(s) by using water ora soap solution prior to demounting the tire from therim. Mark the injured area and totally deflate the tire.Then remove the tire from the wheel being careful toavoid further damage to the tire, particularly to thebead area. Perform a complete internal inspection.

For RV's equipped with dual tire assemblies (duals),if one of the dual tires becomes significantlyunderinflated or flat, the other tire will carry the loadfor both tires, resulting in an overloaded condition.Both tires should be inspected by a tire serviceprofessional for damage. See Tire InspectionGuidelines on page 16 in Chapter 2.

Always read, understand and follow the RMApuncture repair wall charts: "Puncture RepairProcedures for Passenger and Light Truck Tires" or

"Puncture Repair Procedures for Truck/Bus Tires."These wall charts cover the proper repairprocedures for passenger and light truck tiresthrough Load Range "E" and truck/bus tires, loadrange "F" and above. Never repair a passenger orlight truck tire with an injury that is greater than 1/4inch (6mm) in diameter. Never repair a load range"F" and above truck/bus tire with an injury that isgreater than 3/8 inch (10mm) in diameter.

Do not repair an injury outside the puncture repairarea as shown in Figure 13.

Not all tires can be repaired. In addition to the RMApuncture repair procedures, there may be additionallimitations based on individual tire manufacturerrepair policies. These may include the type of servicesuch as speed rating, load index, run-flat technology


Chapter 4, Page 59

Puncture repairs are limited to the tread area as generallydepicted above. DO NOT make repairs where the injurydamage extends into the shoulder/belt edge area OR wherethe injury extends at an angle into the shoulder area. If thereis any question that the injury extends into the shoulder/beltedge area, then the tire must be scrapped.

FFiigguurree 1133:: PPuunnccttuurree RReeppaaiirr AArreeaa

Improperly repaired tires can fail while in service,such as by tread/belt separation, which can leadto an accident and serious personal injury ordeath.

Tires must always be properly repaired asdescribed in the RMA wall charts, “PunctureRepair Procedures for Passenger and Light TruckTires” or “Puncture Repair Procedures for Truck/BusTires, Load Range ‘F’ and Above.”

PunctureRepairArea

and commercial application. When repairing a tirepuncture:

• Never perform a tire repair on-the-wheel • Never use only a plug (stem)• Never use only a patch

The basic principles for proper puncture repair:

• Remove the tire from the wheel for inspection and repair;

• Prepare the injured area;• Fill the injury with a suitable, vulcanizing material

or rubber stem that must fill the injury and keepmoisture out;

• Seal the innerliner with a patch to prevent loss ofinflation and keep moisture out; and,

• Re-inspect the finished repair.

Refer to the RMA wall charts for complete step bystep procedures.

Parking an RV

When parking an RV for extended periods of time, itis important to make sure the vehicle is as level aspossible - not only for convenience and comfortpurposes, but also to avoid over load tire conditionsdue to weight transfers. On RVs without built-inleveling devices, it is customary to "block" the lowwheel positions. Care must be taken to ensure thatthe tires are fully supported when using blocks.

Chapter 4, Page 60


Tire changing can be dangerous and should bedone by trained personnel using proper tools andprocedures. Always read and understand anymanufacturer’s warnings contained in owner’smanuals, on the equipment, listed on websitesand molded onto tire sidewalls.

Failure to comply with these procedures mayresult in faulty positioning of the tire and/or rimparts and cause the assembly to burst withexplosive force sufficient to cause seriousphysical injury or death. Never mount or usedamaged tires or rims.

For more information on tire mounting safetyand procedures, refer to the RMA wall charts,“Demounting and Mounting Procedures forPassenger and Light Truck (LT) Tires” or“Demounting and Mounting Procedures forTruck/Bus Tires.”

If a tire continually loses inflation pressure or haslost all or most of its inflation pressure, it must beremoved from the wheel for a complete internalinspection to check for damage. Driving ondamaged tires is dangerous. A damaged tire cansuddenly fail, including by tread/belt separation,even at a later date, which can lead to an accidentand serious personal injury or death.

Never perform a tire repair without removing thetire from the wheel assembly for an internalinspection. Do not perform an outside-in tirerepair or an on-the-wheel repair.

The photo above is an example of a tire that wasoperated in an underinflated condition with apuncturing object that caused dangerous, non-repairable damage to the innerliner and body plymaterial. This type of damage would not havebeen visible from the outside of the tire.

Every tire must be removed from the wheel for aninspection and to assess repairability.

The load on the tire must be evenly distributed onthe block and in the case of duals, evenly distributedon blocks for both tires. If this isn't done properly,sidewall casing cables may be damaged, which maylead to premature sidewall fatigue and ultimate tirefailure. Refer to Figure 14 for blocking methods forRVs.

Passenger and Light TruckUsed Tires22



Not all tire damage that can lead to tire failure isoutwardly visible. For instance, improper repairs ordamage to a tire’s innerliner can only be observed

by inspecting the inside of the tire, demounted fromthe wheel. A qualified tire service professionalshould inspect the internal and external condition of the used tires prior to application. In the case of aused vehicle purchased by a consumer, the only wayto determine the condition of its tires is to have themdemounted by a tire service professional for thesame type of inspection.

Storing RV Tires23

Stored tires should be protected againstenvironmental effects such as sunlight, high heat,ozone and other potentially damaging conditions.

• Store tires where the area is clean, dry and wellventilated, but with a minimum of circulatingair.

• Store tires in an area with temperate ambientconditions (mild temperatures, shaded or dark).

• Store tires raised off a storage area's floorsurface to minimize exposure to moisture ordamage.

• Avoid contact with petroleum-based productsand/or other volatile solvents or substances.

• Store tires away from electric motors, batterychargers, generators, welding equipment orother ozone generating sources.

Indoor storage is recommended, however if tiresmust be stored outdoors:

• Store tires where they are raised off the ground(or on storage racks) and not in contact withheat absorbent surfaces.

• Protect tires with an opaque, waterproofcovering with some type of vent openings toavoid creating a "heat box" or "steam bath"effect.


Chapter 4, Page 61

Figure 14: TTiirree ““BBlloocckkiinngg”” MMeetthhooddss


22 Refer to RMA Tire Information Service Bulletin, Vol. 45, “Passenger and Light Truck Used Tires.”

23 Refer to RMA Tire Information Service Bulletin, Vol. 23, “Tire Storage Recommendations.”

Incorrect SInglesOnly a portion of the tire is

supporting the full load.

Correct Singles

Duals Duals

IIff ttiirreess aarree mmoouunntteedd oonn aa ssttoorreedd vveehhiiccllee::Store the vehicle such that all weight is removedfrom the tires. If vehicle weight cannot be removed,unload the vehicle to minimize the weight.Maintain the recommended tire inflation pressure,including the spare. The surface whereparked/stored should be firm, reasonably level,well drained and clean.

The vehicle should be moved every three (3)months so the tire flex area is changed.

There is a danger of serious injury or death if a tire of one bead diameter is installed on a rim or wheel ofa different rim diameter. Always replace a tire with another tire of exactly the same bead diameter as thediameter of the rim on which it will be mounted. For example: a 16" tire goes on a 16" rim. Never mount a16" tire on a 16.5" rim. A 16.5" tire goes on a 16.5" rim. Never mount a 16.5" tire on a 16" rim. While it ispossible to pass a 16" diameter tire over the lip or flange of a 16.5" size diameter rim, it cannot be inflatedenough to position itself against the rim flange. If an attempt is made to seat the tire bead by inflating, thetire bead will break with explosive force and could cause serious injury or death. Rims of differentdiameters and tapers cannot be interchanged. The following diagram illustrates the difference betweenrims of two different tapers and diameters:

The following diagram shows how beads of a 16" tire will not seat on a 16.5" rim. The beads cannot beforced out against the rim flanges by using more air pressure because this will break the beads and the tirewill explode with force sufficient to cause serious injury or death.

RReettuurrnniinngg ttiirreess ffrroomm ssttoorraaggee bbaacckk ttoo sseerrvviiccee::Before placing stored tires back into service, a tireservice professional should conduct a visual andtactile inspection to be sure each tire is clean, dry,free of foreign objects, and/or does not show signsof damage. See “RV Tire Inspection Guidelines” on p.54. Once on a rim/wheel, the tire (including thespare tire) should be inflated to the recommendedinflation pressure. See “Proper RV Tire Inflation” onp. 50.

Chapter 4, Page 62


Care and Service of Passenger and Light Truck (LT) Tires€¦ · Chapter 1 - Basic Tire Information...

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