The racing & high-performance tire : using the tires to tune for grip and balance PDF
Preview The racing & high-performance tire : using the tires to tune for grip and balance
THE 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 8
The list of books you might like
