maximum sidewall

TobinH

the whole car is never airborne.

go find the worst pavement in your area... drive at high speed, and hit said pavement while cornering. you will find the car chatters, bangs, and moves sideways.

that's cuz the wheel hits the bump, and is deflected upwards very quickly. the suspension's job is to get it back to the ground in a controlled fashion. but that downwards travel takes time. during that time (which will only be a fraction of a second) you have zero traction - obviously, because your tire is in air.

pneumatic tires are pretty good at absorbing these high frequency hits, and they're better the more air volume available. more sidewall equals more air. of course if you're driving mostly on good pavement, there are downsides, but you know about that.