Quote:
Originally Posted by Sugarphreak
Finally I think you are over looking the big picture, in order to increase MPG you need to reduce contact area or harden the tire to reduce rolling resistance. Both things will result in a comprimise in braking. The only thing I can even fathom why it would somehow defy physics is unless you are trying to say that the weight distributionof the vehicle when braking is somehow impacting that.
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Not necessarily. As long as you're not skidding (creating a thin layer of liquid rubber under the contact area), braking and acceleration forces are limited to the force due to friction. In the simplified view (read constant coefficient of friction), the friction force is independent of contact area as long as the normal force (weight) is the same. If the tire and conditions are such that this holds (which is fairly reasonable since we're not dealing with sand or snow), then the size of the contact patch has no impact on braking or cornering forces up until the tire loses grip.
I don't know enough about tires on road to know if a tire on normal asphalt has a constant coefficient of friction but it isn't a violation of a law of physics for an increase in tire pressure to have no effect on braking or cornering as long as the tire hasn't lost it's grip. The same could hold true in the rain as long as the tire isn't hydroplaning and the coefficient of friction isn't otherwise affected by water.