Passenger Car Tires and Wheels

Günter Leister

Passenger Car Tiresand WheelsDevelopment - Manufacturing - Application

123

Günter LeisterSchwaigernGermany

ISBN 978-3-319-50117-8 ISBN 978-3-319-50118-5 (eBook)https://doi.org/10.1007/978-3-319-50118-5

Library of Congress Control Number: 2017961499

Original German edition published by SpringerVieweg, Wiesbaden 2015© Springer International Publishing AG 2018This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or partof the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations,recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmissionor information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilarmethodology now known or hereafter developed.The use of general descriptive names, registered names, trademarks, service marks, etc. in thispublication does not imply, even in the absence of a specific statement, that such names are exempt fromthe relevant protective laws and regulations and therefore free for general use.The publisher, the authors and the editors are safe to assume that the advice and information in thisbook are believed to be true and accurate at the date of publication. Neither the publisher nor theauthors or the editors give a warranty, express or implied, with respect to the material contained herein orfor any errors or omissions that may have been made. The publisher remains neutral with regard tojurisdictional claims in published maps and institutional affiliations.

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Preface

Tires are developed by tire manufacturers, and cars by car manufacturers.Nevertheless, every vehicle manufacturer has engineers, technicians, and workshopstaff who deal intensively with the topic of tires and wheels. This is because tires arenot just a simple accessory, but rather an integral part of a vehicle’s chassis.Because of this, close cooperation between tire, wheel, and vehicle manufacturers isessential. If no clear interfaces or agreements exist between these developmentpartners, optimal performance of a vehicle chassis cannot be achieved, Fig. 1.

Experience shows that there is no vehicle suspension which can compensate fortires with unfavorable characteristics. Since the tire is one of the few vehiclecomponents which are heavily advertised independently, market studies and per-formance tests are carried out regularly, resulting in strong customer preferencesregarding tire brands. Vehicle manufacturers must take this into account whenchoosing development partners for tires. Ultimately, it is of utmost importance thatboth development partners have an exact understanding of the interaction betweentires, vehicle suspension, and the road.

Wheels are as important as tires. In the “Wheels” chapter, topics surroundingsteel wheels, light alloy cast wheels, and forged alloy wheels are discussed inconjunction with related topics such as wheel bolts and the tire-fitting process.

Fig. 1 Handshake between vehicle and tire manufacturer

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The book does not focus on the basics of tire and wheel technology, but ratherthe processes encompassed by tire and wheel development. Only the physicalrelationships which play a major role in these processes are described. Excellenttextbooks are available which delve further into the technical and engineeringtopics surrounding tires and wheels.

I have to thank the wheel and wheel bolt experts Stefan Beyer, Siegbert Dehm,Roland Eisenkolb, Norbert Oberschmidt, and Jörg Ludwig for their contributions tothis book. The book would not be complete without their expertise.

I would also like to thank Bridgestone, Continental, Goodyear Dunlop,Michelin, and Pirelli for their cooperation and many ideas. In addition, I thank allof the other companies which supported me in this book project.

Readers of this book should send any corrections or suggestions for improve-ment to the email address fahrzeugreifen@guenter-leister.de. These suggestionswill be taken into account for future development of the book.

Schwaigern, Germany Günter LeisterSeptember 2017

vi Preface

Contents

1 Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.1 Tire Manufacturing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.1.1 Mixing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.1.2 Inner Liner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61.1.3 Carcass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61.1.4 Bead Cable and Apex . . . . . . . . . . . . . . . . . . . . . . . . . . 81.1.5 Belt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81.1.6 Tread Rubber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101.1.7 Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101.1.8 Vulcanization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111.1.9 Quality Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

1.2 Tire Development Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131.2.1 Geometry and Load Capacity . . . . . . . . . . . . . . . . . . . . . 141.2.2 Tire Requirements Book. . . . . . . . . . . . . . . . . . . . . . . . . 19

1.3 Project Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261.3.1 Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281.3.2 Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291.3.3 Schedules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301.3.4 Tire Database and Documentation . . . . . . . . . . . . . . . . . . 30

1.4 Mobility Strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 321.4.1 Full-Fledged Spare Tires . . . . . . . . . . . . . . . . . . . . . . . . 361.4.2 Emergency Minispare and Folding Tires . . . . . . . . . . . . . 361.4.3 Tirefit and Self-sealing Tires . . . . . . . . . . . . . . . . . . . . . . 371.4.4 Series-Manufactured Special Tires, Special Rims,

and Supporting Elements . . . . . . . . . . . . . . . . . . . . . . . . 381.4.5 Run-Flat Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

1.5 Testing and Validation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 491.5.1 Indoor Objective Testing . . . . . . . . . . . . . . . . . . . . . . . . 531.5.2 Outdoor Objective Testing . . . . . . . . . . . . . . . . . . . . . . . 791.5.3 Outdoor Subjective Testing . . . . . . . . . . . . . . . . . . . . . . 100

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1.6 Tire Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1111.6.1 Driving and Steering Characteristics:

Forces and Torques . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1121.6.2 Driving Comfort—Noise and Vibrations . . . . . . . . . . . . . 133

1.7 Tire Models and Simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . 1411.7.1 Tire Models for Tire Development . . . . . . . . . . . . . . . . . 1431.7.2 Tire Models for Vehicle Development . . . . . . . . . . . . . . 148

2 Wheels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1572.1 Wheel Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1592.2 Steel Wheels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

2.2.1 Steel Wheel Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . 1652.2.2 Steel Wheel Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1672.2.3 Choice of Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1692.2.4 Steel Wheel Manufacturing Process . . . . . . . . . . . . . . . . 170

2.3 Light Metal Wheels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1762.3.1 Light Metal Sheet Wheels . . . . . . . . . . . . . . . . . . . . . . . 1792.3.2 Light Metal Cast Wheels . . . . . . . . . . . . . . . . . . . . . . . . 1792.3.3 Light Metal Forged Wheels . . . . . . . . . . . . . . . . . . . . . . 193

2.4 Synthetic and Carbon Wheels . . . . . . . . . . . . . . . . . . . . . . . . . . 1972.5 Wheel Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201

2.5.1 Design Drafts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2012.5.2 Choice of Surface Treatment . . . . . . . . . . . . . . . . . . . . . 2042.5.3 3D Volume Modelling . . . . . . . . . . . . . . . . . . . . . . . . . . 2122.5.4 Verification, Operational Stability, and Release . . . . . . . . 2132.5.5 Large-Scale Series Production . . . . . . . . . . . . . . . . . . . . 218

2.6 Quality Assurance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2232.6.1 X-ray, Computed Tomography, and Metallography . . . . . 2232.6.2 Radial and Axial True-Run . . . . . . . . . . . . . . . . . . . . . . . 2242.6.3 Balance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225

2.7 Lightweight Engineering Techniques . . . . . . . . . . . . . . . . . . . . . 2262.8 Aerodynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2282.9 Wheel Trim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2302.10 Wheel Bolt and Wheel Assembly . . . . . . . . . . . . . . . . . . . . . . . 230

3 Tire Pressure Monitoring Systems . . . . . . . . . . . . . . . . . . . . . . . . . . 2433.1 Indirect Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2463.2 Indirect Systems with Diffusion Detection . . . . . . . . . . . . . . . . . 2483.3 Direct Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250

4 Wheel Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2554.1 Valve Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2554.2 Wheel Uniformity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2574.3 Wheel Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2584.4 Matching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2584.5 Filling and Tire Inflation Pressure . . . . . . . . . . . . . . . . . . . . . . . 259

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4.6 Bead Seat Optimization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2594.7 Tire Uniformity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2604.8 Balancing Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2604.9 Quality Assurance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261

Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269

Contents ix

Introduction

Wheels and tires have evolved rapidly in recent years. In the realm of tires, theevolution of the Mercedes S-Class shows this impressively. While the S-Class in1972 (W116) was developed with a tire width of 185 mm on 14-inch wheels,today’s S-Class (W222) has a 245-mm tire width and a 17-inch rim as entry-levelsizes. Figure 2 shows the evolution of tire outside diameters. Development of therim diameter, tire sidewall height, and tire width are shown in Figs. 3, 4, and 5,respectively.

Wheels have evolved as rapidly as tires. Many concepts have come and gone,having been placed in series production after proving themselves, or having simplydisappeared from the market. Figure 6 shows some of the milestones of wheeldevelopment at Mercedes-Benz over the last 45 years. For perspective, considerthat the Mercedes-Benz W108 from the late 1960s was offered with a single 14-inchsteel wheel. In comparison, the current S-Class has a plethora of attractive wheelofferings for customers, Fig. 7. On one hand, these choices represent an enormousdesign challenge for automobile manufacturers. On the other hand, it’s a large

Fig. 2 History of tire dimensions for the Mercedes S-Class

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business opportunity for vehicle and wheel manufacturers. These wheels are notonly offered as original equipment tires, but also as spare parts in the workshops oforiginal equipment manufacturers (OEMs) and as independently advertised itemscf. Fig. 8.

Fig. 3 History of tire outside diameter for the Mercedes S-Class

Fig. 4 Rim diameter and development of sidewall height for the Mercedes S-Class

xii Introduction

Fig. 5 History of tire width for the Mercedes S-Class

Fig. 6 Milestones in the development of Mercedes-Benz aluminum wheels

Introduction xiii

Fig. 7 An example of wheel variants for the Mercedes S-Class (W222) at market launch in 2012

Fig. 8 Aftersales advertisement for original equipment tires

xiv Introduction