Filling the wheel well requires a drop it would seem. I was looking into 18,19,20+ inch wheels. Without balling up your speedo and computer inputs it looks like the same OD is the way to go. I did find a Bridgestone in a 255-45-18. Slightly larger OD (looks better) slightly wider (good thing)...Not off far enough in diameter to cause problems and hose up the already stiff ride. It looks like the wider the tire, the lower the profile. The 265-275-30-20 would ride like an old truck, there is no sidewall !