To start out with, you can fit a 30x9.5 tire on an original rim without cutting. You can fit a 31x10.5 tire on if you flatten the lip on the inside of the rear fenders. Anything wider, and you have to cut. You can go taller, so long as it stays under the 10.5 width. But you start running into flex problems and hitting the fenders as well. It also depends on if you want to put a suspension lift on it or not. Body lifts don't help as much as a suspension lift does, but they do help a little.