First, the stock tires are about 27"-28" and varies on different trim levels. Tires.. SSRs are good, Trxus are better on road but still hold their own off road, esp for a much more reasonable price. If you are driving any highway definately get a radial tire, steer away from LTBs and such, a friend loves them off road but says on road they suck. The backspacing on the wheels that were asked about seems to be about a 3.75" maybe a bit more, maybe 4" I cant really tell that well, they seem to sit way out there, but I really cannot be sure. Stock backspacing is 5.25"... you can assume/guess from there. Running 31's w/o any lift is not a good idea. I ran 30x9.50s for a while w/o a lift. XJs can handle up to 30 w/o lifting, but with rub, mostly in the rear wells from my experience. If you have a newer Jeep and the rear springs arent shot and sagging yet, you should be fine, maybe some rubbing.. I have found most rubbing occured at highway speeds over bumps or frost heaves or such, thats when i heard it. There is def some damage to the tires from rubbing, but they are cheap so im not worried about it. Its all up to you. If you start throwing 30x10.50 or bigger expect to have to trim, and if you throw 30s on there, dont expect to do any serious wheeling, for obvious rubbing reasons.
