If you have the Up Country suspension, you can install a 30" tire. I had a 30"/9.50R15 tire, Michelin tire was the best tire for the vehicle. We ran the LTX A/T, great riding. Or you could run the new cross terrain, which rides very well.
You will need to check the tire clearence when turning. Mine had a good 1/2" from the front corner while turning.
31" would hit in turns when turning.
You could have the tire store install one, and check it on both front corners.
[FONT=Trebuchet MS]01' Jeep TJ (Jeep #5)
3.5 RE Custom SuperFlex, Raingler, Kilby, Currie, Banks, Borla, American Racing, Custom mods, Always more in the works.