I have 33x12.5x15 on my truck now, stock suspension, and my tires have never rubbed..
Tho one when making tight right turns hits my pitman arm, is that a normal problem?
Then you just haven't tried hard enough

A lot has to do with backspacing and rim width. 4" of backspacing and an 8" wheel will keep everything in the fender better, but I bet they will still rub.