Originally Posted by 
rick130
				 
			Yep, but that's my point, you can make a tall tyre for a 13" rim work well at high speed/huge loads.
There are some trick tyres available in motorsport to suit size regs, and as you've mentioned compliance is a good thing to have, as is having a reasonable tyre spring rate.
We don't need 40 series tyres on modern cars, they aren't necessary from a handling/road holding POV, but style dictates people want large rims.
60% aspect ratio seems to be the current sweet spot between compliance and not too much distortion, rally and off road racing (not including the US off road race scene) after to have settled on that profile.