Depends. What backspacing? Is this on the rear? I have 15x8 aftermarket rallys on the rear of mine, with 4 1/2" backspacing. I have 295-50x15`s on them. I do have the quarter panel lips turned up. They are very tight and i would probably go with a 275 if i had it to do again. A factory 15x8 rally wouldn`t work on mine, didn`t have as much backspacing as the aftermarket rally.
Terry