Weaver Cerritos Ford Tire Failure case

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Transcript of Weaver Cerritos Ford Tire Failure case

ILLUSTRATION TYPIFIES TIRE CONSTRUCTION BASED ON INFORMATION PROVIDED BY THE MANUFACTURER. FEATURES ARE NOT TO BE INTERPRETED AS PRECISELY SIZED OR SCALED(DISCOUNT TIRE)

CONSTRUCTION OF THE DOMINATOR A/S

TREAD

SECOND STEEL BELT

INNER LINER

FIRST STEEL BELT

TEXTILE BODY PLY

SIDEWALL

OBSERVATION OF THE DISABLED TIRE

TREAD AND SECOND BELT

BODY PLIES AND FIRST BELT

Trace of the Separation

Localized abnormal wear

Most worn area

Tread

Sole (Second Belt)

TREAD/BELT OBSERVATIONS OF THE SEPARATED TREAD/BELT

DIRECTIONS OF PROPAGATION OF THE SEPARATION

SEPARATED AREA

DIRECTIONS OF PROPAGATION

TREAD PLACEMENT OVER THE AREA OF SEPARATION

TREAD

SEPARATED AREA

1”

5”

20”

7”

DIMENSIONS OF THE SEPARATIONAT THE ACCIDENT

2.74

4.55

2.693.04

4.09

3.673.21 3.50

3.222.35

1.6 1.47

2.09 1.431.01 .74 .99

2.24

Tread Grooves measurements

Most WORN Groove

Tread Depth 4.39 mm (5.53) 32nd)

Tread Depth .74 mm (.93) 32nd )

Tread Worn = 8.73-4.39 = 4.34 (5.47) 32nd)

Tread Depth difference = 3.65 mm (4.6) 32nd)

0 200 400 600 800 1000 1200 1400 1600 18000

20000

40000

60000

80000

100000

120000

f(x) = 17.9669334717765 x + 68418.1801427007R² = 0.999249007286767

Tire HistoryRate of Tire Usage

Cumulative Days

Odo

met

er

TIRE MILEAGE68931

LAST INSPECTION

1848 MILES

Accident

THE TIRE WAS 4 YEARS 2 MONTHS OLD AND HAD BEEN MOUNTED ON THE VEHICLE 2 MONTHS AFTER IT HAD BEEN MANUFACTURED AND HAD BEEN DRIVEN 29934 MILES AT THE TIME OF THE ACCIDENT 11/12/2012CERRITOS FORD EXAMINED THE TIRE 1848 MILES BEFORE THE ACCIdent

TIRE HISTORY

CALCULATION OF THE RATE OF WEAR

OUTSIDE THE ZONE OF SEPARATION THE RATE OF WEAR CAN BE CALCULATED

NUMBER OF MM WORN = 4.34 MM NUMBER OF MILES DRIVEN = 29934 MILESNUMBER OF MILES PER MM = 29934 / 4.34 MM = 6897 MILES PER MM OR 5448 MILES PER 32ND

WE NEED TO DETERMINE THE RATE OF WEAR OF THE AREA OVER THE SEPARATION.

WE USED THE CONCLUSION OF A TEST I CARRIED WHICH RESULTS WERE PUBLISHED IN RUBBER AND PLASTICS NEWS .

05/02/2023 Abnormal Wear over Belts Separation 13

PAPERS( PUBLISHED R & P NEWS JULY 23, 2007

AND R & P NEWS NOV 17TH 2014 )

 

TREAD WEAR RATE OF THE TEST IS 2996 MILES PER MM

THE WEAR RATE OF THE DIFFERENCE BETWEEN THE MOST WORN GROOVE AND THE AREA NOT SEPARATED IS 1297 MILES PER MM.

THE DIFFERENCE WEARS 2.3 TIMES FASTER THE RATES ARE NOT DEPENDENT OF THE SIZE OF THE SEPARATION.

CONCLUSIONS OF THE TEST

Tire mileage is 29934 Tread worn is 4.34 Consequently tread wear rate 29934/4.34 = 6897 miles per mmTread wear rate of the test 2996 miles per mm

The accident tire wore 2.30 times less than the test tire

ACCIDENT TIRE WEAR RATE

ACCIDENT TIRE TEST TIRE

ABNORMAL WEAR

NORMAL WEAR 2996 MILES/MM

1297 MILES/MM2996 MILES/MM

6897 MILES/MM

WEAR 2.3 TIMES FASTER

2.3 TIMES SLOWER

To reach 3.65 (difference in the accident tire)The mileage is 2996 X 3.65 = 10936 miles

2.3 TIMES SLOWER

First method

Second method

Number of miles to reach 3.65: 2996 X 3.65 = 10936Abnormal Wear at the dealership : 3.65: 10936 X (10936-1848) = 3.03

Number of mm worn in 1848 miles = 1848:2996 =.617 mmDifference of Tread depth at the dealership = 3.65-.617 = 3.03

TIMELINE

ACCIDENTTIRE BOUGHT START OF SEPARATION AND ABNORMAL WEAR

10936 MILES18998 MILES

INSPECTION BY CERRITOS FORD

1848 MILES

11/12/2012

08/22/2012

04/09/2008

AW=3.03 AW=3.65

0.00 5000.00 10000.00 15000.00 20000.00 25000.00 30000.00 35000.000.00

2.00

4.00

6.00

8.00

10.00

12.00

11.00

7.53

5.875.53

11.00

7.53

2.05

0.93

Grooves Tread Depth (32nd) (Normal and abnormal Wear)

Mileage of the accident Tire

Tre

ad D

eptt

h (3

2nd)

NORMAL WEAR

START OF THE SEPARATION

MOST WORN GROOVE

ABNORMAL WEAR

NORMAL WEAR

NEW TIRE11 32ND/8.73 MM

DIFFERENCE OF TREAD DEPTHAT THE DEALERSHIP

3.81 32ND/3.03 MM

START OF THE SEPARATION7.53 32ND/5.98 MM

DIFFERENCE OF TREAD DEPTHAT THE ACCIDENT

4.59 32ND/3.65 MM

Final Result

Upper 95 % MEAN Lower 95 %

mm 3.5 3 2.5

32nd 4.4 3.8 3.2

ABNORMAL TREAD WEAR AT THE DEALERSHIP

ABNORMAL TREAD WEAR AT THE ACCIDENT

ABNORMAL TREAD WEAR AT THE DEALERSHIP

3.81 32nd

4.6 32nd

2 32nd