[ZOA NOM]

The math sez you would just change the RPM range a little bit. Taller tires should mean lower rev's at launch, and throughout the RPM range for the speed you are travelling. It can help on a longer straight, but might hurt in a tight turn where you want higher rev's at exit. You could almost gear your car for a specific track with different size tires. I would say, on a course that you never reach top end, a taller tire would hurt more than help, all else being equal.