Not to pick, but the formula for on road is actually 75% of your tread width should be sidewall for optimal ride and comfort. i.e. 235/75R15 tire is expressed as:KaiserJeep said:It's not like there is no downside. Ideally for safety, handling precision, and to better protect the tire when aired down, you want the wheel to be half of the total tire diameter, and the rubber to be half. The further you get from the ideal formula, the lower the performance both onroad and offroad.
15" wheels should be OK with up to about 33" tires. 16" wheels OK for up to about 35" tires. 17" rims for up to 37's.