If your truck has a larger than factory exhaust system or a short bed or both, the Torklift Superhitch will reduce the size of what spare tire you can carry. I carry a 285/70R17 and it is the absolute maximum; I'm pretty sure if I didn't have air bags that the tire would rub on the diff cover. It has never hit, but it's damn close, and I rotated my spare into the rotation in hopes that it will wear down some and give me a little more clearance! If your truck is a long bed, you won't have to worry about this as much, I don't think, as I believe a long bed is at least slightly longer between the rear axle and bumper, despite the fact that most of the distance is between the cab and axle.