Which t-case do you have?
With the NV247 (Quadra-Trac II) it's imperative to run the same sized tires all around. It's been suggested to me that with these t-cases the spare should be the same and included in the rotation.
With the 242 and open diffs, the difference in size won't cause a problem.
So I installed the flux capacitor but the Jeep just won't do 88 mph.
-'99 WJ Limited, 4.7, Patriot Blue, 2" BB, 31" Mall-Terrains, Pavement Princess
-'97 TJ, Stone White, 4" Superlift, 33" SSRs, lunchboxed rear, 12K Titan winch, and 2.5 litres of exhillirating performance.