You will notice a difference in your gearing if you go up to 31's. If it's a manual, you will lose the use of 5th gear unless your really moving down the highway. It's about the maximum size you would want to go up to without changing ring and pinion gearing.
89' YJ - 4.2 - NV4500 - NP231w/sye - 1" Body Lift - 2 1/2" Rancho Suspension Lift - 31" Firestone MTR - AR Outlaw II - Tomken Bumpers F & R - Warn 8000 front - Warn 6000 rec. mount rear - FlowFit Seats - Tom Woods Rear & Custom 2" front driveshafts
w/ a manual u will NOT lose 5th gear with 31's....at least if you have the 6cyl. but your speeds at which u will get into that gear w/o boggin down will be like 5 mph higher. If you have the 4-cyl than u may lose 5th but get a full borla exhaust/chip/intake and you should be in good shape. hope this helps
I have 31s on my TJ I used a 1.5" spacer lift from procomp. . .you will have to add 3-4 washers to your bumpstops up fornt other wise you will rub when you disconnect the sway bars. . ..if you leave the sway bars connected and you use factory offset wheels you are ok except at full lock when turning you will gwt some rub here but just alittle if you go with new wheels with std or 4.5" offset you will have no rubbing but the tires will set a little outside the fender flares so mud and dirt will flip up the side or in if you run without doors. . .I would recommend going with a 1.75 or 2" spacer that comes with bumpstop extensions. . .like Daystar or Teraflex. . .
hope this helps