[Ron Sutton]

Hey Ron, another question for you...

You mentioned that in Gaetano's case he might as well have just thrown 275 tires on the back of the car instead of the 315s because he would need to remove the 15.x percent more grip that the 315s added in order to get the car balanced again.

My question is, if you're working with more tire in the back versus the front, can you tune the rear to have more grip in the straights and less under steady state cornering?

Good question. Tough answer.

First, What is this steady state cornering you speak of? I'm kidding, but only a little. The car is almost always in transition. Even in the "roll through zone" ... after the driver is off the brakes & has not picked up the throttle yet ... the car is decelerating (coast down) so the speed is changing ... "settling" in pitch (nose wanting to come up & rear down) ... and increasing in roll angle a small amount more. On long sweeping corners the car might be in the "same state" for a second. But on most road courses, short to medium ovals & AutoX, the car is constantly "transitioning."

When I'm working with a race driver, we break each corner down to three sections ... and if that is not enough detail, we'll break it down to all 5 or 6 driving actions. The three sections are Entry (braking & turn-in), Middle (roll through zone, coasting, no brake or throttle) & Exit (throttle roll on & steering unwind).

If the car is doing something difficult to sort out, the driver & I will break it down to what happens at each step: Brake application, steering input into the corner, steering set, brake release, roll/coast, a sharp steering "cut down" if there is one, steering unwind & throttle roll on.

You can make the larger rear tired car turn great on entry & have awesome grip on exit. The middle is always the challenge. The bigger rear tires make it hard to roll the center at optimum speed without pushing. And the ironic part is, the mid corner push caused by the larger rear tires ... CAUSES the car to "snap loose" on corner exit ... and be loose on exit.

If you can get a handling car to turn well in the middle, without pushing, it won't "snap loose" on exit ... and if tuned right ... will have more grip on exit, than if we were fighting a tight or push condition in the middle from larger rear tires.

Just so everyone is clear:
A. There are lots of suspension tuning methods to improve rear tire grip on corner exit. Having bigger rear tires is just one.

B. I'm not saying you can't run bigger rear tires and have a good handling car, but when they difference gets significant, you designed in handling problems for yourself.

C. There are situations where we want bigger tires in the rear, than the front, but it is when the car's weight balance is rear heavy.

D. Otherwise, having the same size tires front & rear, makes it easiest to create a well balanced handling car, that will be fastest on track.



Matt