Friction, physics, and racing

[dinomite]

Ok, we are doing frictin in my physics class, and we just today went over the fact that friction is independant of surface are, and i believe that. but i also know that putting wider tires on your car (of same type) gives you the ability to launch harder, but if friction is independent of surface area, why is this so? I talked to my physics teacher and he was very confused, cause obviously he believes the law that friction is independent of surface area, but he knows that my statements are valid as he knows that i know alot about racing. he talked to the other physics tachers at my school, one gave some odd conveluted answer, the other simply agreed with physics laws.

This applies in two ways, one in drag racing where your trying to begin movement from a standstill. it also applies to cornering, where the tires keep you from sliding off the road, they are pretty much the same thing. My teacher just said that bigger tires were for heat dissapation, which is part of road racing and they do engineer tires for that in some ways, bt thats not the case, and its definently not applicable in drag racing. All of us here know that putting wider tires on can give you better traction, and thats why we do it, and they limit tire sizes in all types of racing for that reason.

Any thoughts?