I've got 31's on stock cherokee rims on my 91yj.I'm also running a 1" shackle lift. I've stuffed the tires pretty deep, and haven't smacked them into the fenders. I still need to adjust my bumpstops. I do get a bit of rubbing on the springs when I turn really sharp.
My next project is to build some tubular fenders for the front to see if I can run 33's without a lift.