I'm running 31" under my 94 YJ with 3" lift...and there's plenty of room for more tire, but not enough engine to move them. Started with 31" x 12.5's on Rubicon Moab rims...but they were too heavy and too wide...just no 'balls' under the pedal with them. Got rid of them, went to steel 15" x 8" rims and put 31" x 9" tires on...and got some umph back to it. Still harder than anything to get it up to 55 and hold it there...lots of shifting. So I must have low gearing...it's unstoppable on the trails and rockcrawling, just no speed on the highways. Don't think you can have it both ways...pick what you want to do and live with it. Big tires, slow speed...or smaller tires and highway driving.