If you disperse the load(weight of car) over a wider area then there is less actually holding it down, you are correct but there are limits to where the grip will be sacrificed, as water on the road could lift the car up slightly, I have no facts but the laws of physics will come in somewhere to underline this.
Damn good point! You're right - as tyre size grows and so more tyre touches the road, the weight on each square inch of rubber will be massively reduced. My physics isn't even slightly good enough to come up with an answer. Theres probably an optimum depending on weight vs torque of each car.
PS... Sorry, hijack over as my brain is melting!
