Just bought 18's with 255's in the rear and rubs when I go over big dips on the freeway. It doesn't rub on hard cornering so plan on using 245's instead when current rear tire wears out. Slight oversteer or will I be ok? I'm not tracking these rims and will have a dedicated set for that. Thanks for any input.

 

For street driving I don't see any problem at all. You can also try running a little more negative camber in the rear or rolling the fender lips.

Jim