ausrobbo

I agree that managing the contact patch, for all practical purposes, is the way to improve cornering performance. It may or may not be the size of the contact patch vs the forces you apply on the patch, but the logic to balance the chassis and the weight on each tire gives the same result. I don't see this is contradicting anything of the Code principals.

If you read through the article I posted a link to, it concludes that wider tires primarily are for wear reasons. As we all know, a rubber tire sacrifices itself to provide the friction (all the gum balls on your front tire after a track session prove this is so). A small tire dealing with significant friction demands, and in drag racing probably being overloaded will wear fast. So if you had the smallest tires that could support the weight of the car and did a run, you would likely destroy them due to friction heat and mechanical stress. If you were really serious about winning a drag, you could have single pass tires that had just enough strength for a run and then die. They would be smaller and lighter. But you would change tires every single pass. So the extra rubber is for wear and handling of forces - vertical, lateral, roll on the sidewalls/carcass, flex to absorb acceleration and deceleration shock, bumps and so on. It doesn't provide more friction or grip.

If that didn't compute for some folks, remember friction is proportional to the normal force applied between the two surfaces. On a flat road, that only comes from Gravity. On a banked corner just standing still you feel like you might slip down, because you have less friction (Gravity is not perpendicular to the surface, so you have less force creating less friction). When you ride at speed around a banked turn you get more friction leaned over because some of the inertia will add to the normal force and increase friction. This is why you can go faster on a banked turn. Likewise, as stated in Twist II, as you come off a banked turn you need to watch your lean angle, because friction will reduce and therefore your demands on grip might exceed what you have. I don't think it actually because the lean angle increases, for if you are on the same arc and have the same lateral forces applied your demand for grip has not changed, but it is because the amount of grip available decreases.

Slightly off topic, but this is not correct. The contact patch size has no impact on traction. It is a complex topic, and I like this explanation best http://www.stevemunden.com/friction.html. The second law of friction states "Friction has no relation to contact surface area". Friction depends entirely on the Force (not pressure) applied between the two surfaces. If we assume the rubber compound and road surface of both tires are the same at any given point in time, the grip on front and rear has nothing to do with the size of the contact patch and only to do with the amount of force applied. Moving around on the bike changes the forces applied to the tire and the MotoGP style uses less of the available friction than other styles - it is not because the contact patch is different specifically. The grip at all angles of lean on the same tire on the same surface is the same.