Your Jeep is geared 4.11 with a D35 in the rear and 4.10 D30 in the front, which is one of the many nice things about the 97 2.5 TJ. I have the same Jeep with a 3" lift and 15x7 rims. I currently have 33x10.5R15 BFG AT on mine. You really don't want to exceed 10.5 width with 15x7. The 4.0 TJ were stock with rear gearing at 3.73 which is why you read so much about people having to regear with the 4.0. If you have a manual 5 speed, just shift gears at a higher rpm and you will be fine. If you have an automatic, consider regearing to 4.88. On day when I have enough money to throw around, I will regear to 4.88, but for now the 4.11 works fine
YES ON THE 10.50s! Sure you can squeeze 12.50 tires on your 15x7 rims, but then you are putting to much stress on your vehicle and at that point you care more about the "look" instead of safety or function.
I have a similar 97 TJ and am currently running 31x10.5 Big O AT's which I love. No issues with running them except for uphills. I did go with 15x8 rims to eliminate the backspacing issues and some rubbing. The GY Duratracs are a great tire too!
I get right around 15mpg city driving in Dallas. I would be getting better, but need to clean the throttle body componets thanks to the K&N air filter dirting up my IAC... I noticed around 2-3mpg increase when I finally got rid of the 12.50s
I would call a dealer and with your VIN number request a build sheet. I have 3:07's on a 98 6cyl auto D35/30. I would need to re gear with 33's. Have 31" BFG AT's and love them even though they suck in the mud. Will get the DuraTrac's next year maybe. I hear they are amazing tires!
^ he has the 2.5 not the 4.0... 2.5 is geared 4.11 D35 rear, 4.10 D30 rear. Sitting on hold calling the dealership is a waste of time. If you have any doubts, look at the rear diff and you will see a tag at the 9 oclock position. Same with the front. This is why so many 2.5 owners get confused with regearing. 4.0 owners usually (unless they took the dealer upgrade option) have the 3.07 or 3.73 (except the all mighty Rubicons). With the 4.0, 3.07 you better regear with 33s or else. The 2.5, not so much