Table Of ContentTHE RACING &
HIGH-PERFORMANCE
TRE
PAUL HANEY
Using the Tires to Tune for Grip & Balance
THE RACING & HIGH-PERFORMANCE TIRE
Using the Tires to Tune for Grip and Balance
by
Paul Haney
offing
THE RACING & HIGH-PERFORMANCE TIRE
2
Co-published by TV MOTORSPORTS and SAE.
© by Paul Haney, 2003. All rights reserved. With the exception
of quoting brief passages for the purpose of review, no part of
this publication may be reproduced by any means without
written permission from Paul Haney.
ISBN 0-9646414-2-9
TV MOTORSPORTS
31 Tophill Lane
Springfield, IL 62704 USA
email: [email protected]
http://www.insideracingtechnology.com
SAE Order No. R-351
Society of Automotive Engineers, Inc.
400 Commonwealth Dr.
Warrendale, PA 15096-0001 USA
email: [email protected]
http://www.sae.org
Printed in the United States of America.
First printing January 2003
The information in this book is true to the best of our knowl
edge. All recommendations are made without any guarantee on
the part of the author or Publishers, who disclaim any liability
incurred in connection with the use of any information pre
sented here. Any opinions expressed here are entirely those of
the author.
Photos included here were taken by the author unless other
wise credited
Cover design by William Nagel of Redwood City, Calif., who
also consulted on the layout and design of the body of the
book.
ZN
CONTENTS 3
Contents
Illustrations and Tables
9
Introduction ............ 15
Chapter 1 How a Car Turns a Corner 19
Vehicle, Tires, Driver 20
Slip Angle.. 20
Footsteps 21
Lateral Force vs. Slip Angle 22
An Automobile Is Easier to Make Than a Tire 22
The Complexity Is Daunting 23
Chapter 2 Rubber 25
Rubber History 26
Obsession 27
Serendipity 28
The Beginnings a Recipe 29
Parallel Development 30
Synthetic Rubber 30
Rubber Is a Polymer 31
Rubber Is Elastic and Viscoelastic 33
Creep Test. 33
Mechanical Model for Rubber 34
Speed Sensitivity 34
Rubber Response to Cyclic Stress 35
The Glass Transition Temperature 36
Chapter 3 Rubber Friction
37
Simple Friction 38
Rubber Friction 38
Adhesion 39
Deformation: Mechanical Keying 40
Tearing and Wear. 41
Total Friction 41
Deformation Friction and Viscoelasticity 41
Adhesive Friction and Surface Deformation 43
Friction: A Combination of Forces 44
Road Surface Effects 46
Shape 47
Slope of the Asperities 48
The Myth of Off-Line in the Rain. 50
The Load Sensitivity of Rubber Friction 50
Temperature and Speed Effects 52
Chapter 4 Rubber Compounding 55
Which Rubber? 56
Recipe for a Tire. 57
Carbon Black Reinforcement 58
Vulcanization ...... 61
Additive Development 62
4 THE RACING & HIGH-PERFORMANCE TIRE
Chapter 5 Tire Design and Manufacture 63
..........
Structure of the Pneumatic Tire 8565884858
Modulus of Elasticity 64
Fatigue Strength 65
Fatigue Failure 66
Tire Design 66
Contact Patch Load Effects 67
Structural Distortion Due to Vertical Load 68
Load and Internal Pressure %70
A Loading Example 270
7
Overloading and Underinflation 71
Braking and Acceleration Forces %72
Bias-ply or Radial? 仍73
Street Tires vs. Race Tires 叫74
小
Wider Wheels 74
Tire Construction 乃75
Construction Details 形76
Reinforcing Cords 刀77
Filament, Thread, Yarn, Cord 四79
Adhesive Coatings on the Cords 四79
Tread Design.. %80
Tread Patterns for a Wet Surface 880
Tire Noise a81
Special Case: Sports-Utility Vehicles %82
Manufacturing Process %
82
Tread Material %
84
Assembly
85
88
Tire Nonuniformities
86
The Hazards of Batch Processing
87
Manufacturing Developments
88
The Tire Industry Isn't Healthy
89
Automated Manufacturing
89
Chapter 6 Tire Behavior
91
How a Car Turns a Corner: Revisited
92
Slip Angle
92
Lateral Force vs. Slip Angle
94
Longitudinal Forces.
95
Combined Forces
96
Friction Circle 97
Lateral Deformation of the Tread 97
Wide Tires Are Better ....
99
Why Wider Tires Are Better 101
Self-Aligning Torque
102
Vertical Forces in the Contact Patch
104
Dynamic Tire Response to Steering
106
Rolling Resistance
107
Induced Drag
107
Radials Are More Efficient
108
Camber Thrust.
109
Construction-Induced Camber
110
Stagger
110
Internal Pressure
111
CONTENTS 5
Tire Dynamics: Standing Waves 112
Frequency Response 113
Load Sensitivity of Tires 114
Lateral Speed of the Tire. 116
Chapter 7 Balance and Control 117
Oversteer and Understeer 118
Consequences of Imbalance 119
The Driver Is Important 119
What the Tires See 120
Again, Drivers Can Make a Difference 121
Control at the Limit of Adhesion 122
So Tight It's Loose 123
Chapter 8 Race Tires 125
Break-in 125
Scrubbing Race Tires 126
Pre-Scrubbing Tires 127
Shaving Tires 128
Tire Temperature and Pressure 129
Taking Tire Temperatures. 130
Tire Give-Up 133
Tire Wars: Goodyear vs. Firestone 134
Here Comes Firestone 136
Firestone Tires Proved Superior 137
Less Give-Up Can Be a Problem. 138
Why Didn't Goodyear Respond with a Competitive Tire? 138
NASCAR-Hoosier/Goodyear Comparisons at Daytona 139
Asymmetrical Sidewalls 140
Heat Cycles 141
Abrasion and Graining 141
How Firestone Whipped Goodyear 143
Graining on Dirt... 144
Graining on Pavement 149
Blistering. 150
Tire Treatments 151
Tire Treatments Are Widely Available 152
Hot Lap, Hot Lap II, and LMT 153
Did Gordon's Car Use a Tire Treatment? 154
Tire Companies Do Not Like Tire Treatments 155
A Tire Guy Speaks Out 155
Chapter 9 Tire Testing and Development 165
Tire Testing ........ 166
How Important Is Tire Testing to a Team? 166
Driver Feedback Helps Develop Tires 167
Paul Gentilozzi on Tire Testing 168
Mario Andretti: Tire Development History 170
Interesting Times Indeed! 175
2002 Formula 1 Tire War 176
185
WLF Transform
Ten Ferrari Engineers at Bridgestone? 186
Barrichello's Tire/??? Incident at the USGP 188
6 THE RACING & HIGH-PERFORMANCE TIRE
189
Chapter 10 Tire Performance Data
190
Engineers Want More and Better Data
190
Simulation Software
192
Typical Tire Data
193
Spring Rate
194
Rolling Radius
195
Lateral Force vs. Slip Angle
196
Load Sensitivity
196
Self-Aligning Torque
198
Formula 1 Tire Data
200
MTS Flat-Trac Tire Testing System
202
Missing information
Motorsports Drives Development. 202
Chapter 11 Basic Vehicle Dynamics 203
The Physics: Newton's Laws of Motion 204
Inertia and Units 205
FEMA for a Circular Path 206
Inertial Forces and Lateral Weight Transfer 207
Weight Transfer Calculation 209
Fractional Weight Transfer 210
CG and Lateral Weight Transfer Examples 211
212
re Roll ...
Longitudinal Weight Transfer 212
213
Suspension 'Anti' Geometry
Anti-Dive and Anti-Lift with Braking 213
Anti-Squat with Acceleration 214
215
Anti Trade-Offs
Lower CG Is Better 216
CG Is Important: Winston Cup Cars at Martinsville 216
Typical Independent Suspension 217
Roll Centers 218
Cornering Forces 219
Jacking Force. 221
222
Roll Center Position Trade-Offs
Timing of Forces .. 222
Dynamic Suspension Movement 224
Special Case: The Panhard Rod. 224
226
Details of Lateral Weight Transfer
Unsprung Weight Transfer 227
Sprung Weight Transfer: Direct Forces and Roll Forces 228
Direct-Force Weight Transfer 228
229
Roll-Force Weight Transfer
Weight Transfer Calculation 231
Roll Angle 232
Chapter 12 Suspension Geometry 233
Camber Control 234
235
Roll- and Ride-Height Effects
Aerodynamic Constraints. 235
Steering Geometry 237
Caster 238
Karts and Caster and Tires 238
CONTENTS 7
Mechanical Trail 239
Ackermann Steering Geometry 239
Toe 241
Bump Steer, Roll Steer 242
Chapter 13 Tuning for Grip and Balance 243
Tuning the Racecar By Levels 244
Ride Height . 245
Static Weight Distribution 245
Moment of Inertia 245
Corner Weights 246
Spring Rate, Wheel Rate, Tire Rate 246
Bell Cranks and Third Springs 247
Where to Start with the Basic Setup 249
Starting Points—Springs and Bars 250
Sizing Anti-Roll Bars 250
Suspension Antis 252
Diagonal Weight Transfer: Wedge 252
Using Wedge to Adjust Balance 254
A Static Adjustment with Dynamic Results 254
A Doubly Powerful Adjustment 255
Cockpit-Adjustable Wedge. 255
Wedge Summary 256
Wedge with Tire Pressures 256
Dynamic Tire Loading 257
Roll Resistance 258
Roll Resistance Distribution 259
Roll Resistance Trade-Offs 259
Geometric Stiffness 260
Choosing Initial Roll Centers 260
Roll Center Stability 261
Roll Timing 261
Spring Preload 263
Springs, Bars, and Dampers 264
The Anti-Roll Bar 265
Skid-Pad Testing 266
Springs and Bars: Choices 267
Damper Detail.
268
Damper Adjustments 270
Tire Loads for Specific Adjustments 271
Index 277
References 283
Resources 285
THE RACING & HIGH-PERFORMANCE TIRE
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