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updated 7/25/2007

Tire & Handling Seminar

New Content

The seminar has evolved as I've learned more and figured out how to better explain some of the more complicated topics. The viscoelastic nature of rubber and rubber friction generates a challenge to racers trying to tune a car for maximum grip.

"The car feels like it's up on top of the track instead of down in the track," is a dreaded driver comment but actually is a good intuitive description for what's happening when lateral load transfer timing or damper tuning causes actions at the contact patches that the tires don't like. I've added considerable content explaining lateral load transfer timing and how that timing effects grip and how the car feels to the driver.


Content Summary

How a Car Turns a Corner: Paul begins each presentation with an explanation of how a tire generates a lateral force with a slip angle and how that allows a vehicle to turn a corner with control at high speed. He returns to this topic later to cover it in more detail.

Rubber & Rubber Friction: A short history of rubber covers the discovery and development of this amazing material and introduces some of its unique characteristics. The way rubber interacts with a surface to produce friction forces is complex. You'll learn about rubber's sensitivity to temperature, sliding speed, surface texture, and vertical loading. Discover the real reason why there's more grip off-line in the rain.

Rubber Compounding: Learn about rubber choices and how carbon loading and the vulcanization process modify rubber characteristics. The complex nature of tires starts with rubber.

Tire Design and Manufacture: Explains how tires can be flexible but strong while describing some design goals and structural variables. You'll learn why inflation pressure is so critically important to tire performance and reliability. See how a tire generates heat as it rolls.

Tire Behavior: Detail explanation of how a tire produces lateral force and turns a car. See the importance of camber thrust, induced drag, aligning torque, the friction circle, and load sensitivity. Learn the real reason why wide tires produce more grip.

Balance and Control: Explains understeer and oversteer and describes how good drivers maintain control at the limit of adhesion.

Race Tires: Shows how to take tire temperatures and describes scrubbing, blistering, and graining. Explains how to find the right inflation pressure. Presents typical data provided by tire manufacturers to some race teams and discusses whether this data is actually useful.

Basic Vehicle Dynamics: Presents an understandable explanation of the physics of a car in a corner, describes lateral and longitudinal weight transfer, and presents the importance of roll centers and how to calculate the different components of lateral weight transfer.

Tuning for Grip and Balance: Explains how to tune a racecar one level at a time. Learn the difference between spring rate, wheel rate, and tire rate and read how to choose initial spring rates, anti-roll bar rates, and roll center locations. What is geometric stiffness and why is it so important? Learn the importance of wedge and how both anti-roll bars and dampers produce wedge effects that help balance a car and generate grip. Learn how dampers and roll center heights change lateral load transfer timing and why this is so important. See a sequence of tuning changes and how those changes affect tire contact patch forces. Learn why a front anti-roll bar is so useful.



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