Another 2.5 tire size question

RyanMkTJ

Member
Original poster
Joined
Sep 26, 2020
Messages
67
Location
Oregon
Hey all,
I've read the many threads, and i know there are a lot out there, please don't hate. I have a 98' with the dreaded 2.5L auto combination, stock 3.73 gears. It currently has 28's on 15x8 wheels. It feels like a death trap above 60 which is a speed I don't exceed. I wan't to put a 31 on the jeep. From what i've read it seems that I can still achieve my cruising speed of 60 with 31's. Also have people had clearance issues at stock height?
I wanted some confirmation before i purchased.
Thanks for answering this for another newb.
 
Last edited:
You'll want a 1" spacer ideally to clear a 31".

You have the worst combo ever put in a TJ however, so even with a 31" it is going to suck big time. However, it probably sucks as it is now (as you've mentioned), so just prepare for it to suck even more.

Re-gearing will help.
 
A Jeep with an automatic trans and a 2.5 should be rolled over a cliff (accidentally of course) and insurance collected. Take said insurance check and apply towards new Jeep. I run 31” tires with a manual trans 2.5 (has 4.11 gears) and it is a dog with fleas. 5th gear is pretty much lost unless you are going downhill with a tailwind. I fight the battle, daily, on whether to spend another dime on this old gal (1998).
 
You'll want a 1" spacer ideally to clear a 31".

You have the worst combo ever put in a TJ however, so even with a 31" it is going to suck big time. However, it probably sucks as it is now (as you've mentioned), so just prepare for it to suck even more.

Re-gearing will help.
I must be crazy because I actually don’t hate it. Or maybe because it’s my first Jeep I don’t realize how much better life could be. Good tip on the 1” spacers.
 
  • Like
Reactions: D M and Chris
A Jeep with an automatic trans and a 2.5 should be rolled over a cliff (accidentally of course) and insurance collected. Take said insurance check and apply towards new Jeep. I run 31” tires with a manual trans 2.5 (has 4.11 gears) and it is a dog with fleas. 5th gear is pretty much lost unless you are going downhill with a tailwind. I fight the battle, daily, on whether to spend another dime on this old gal (1998).
I think petty fixes like leaks and creaks are what drive me crazy! While I agree it’s slow and dull to drive I’m not sure if I’m ready to go the cliff route. I’ll keep that in mind tho. I do SERIOUSLY with i had the 5 speed tho. Why TF didn’t Chrysler put in an overdrive gear in the auto.
 
I owned a new 2000 (60th Anniversary) TJ that had the 4.0, rear Dana 44 and auto trans. I cannot remember the ring and pinion gear ratio. The auto trans buzzed so bad at highway speeds that I sold it after 8 months.
 
I owned a new 2000 (60th Anniversary) TJ that had the 4.0, rear Dana 44 and auto trans. I cannot remember the ring and pinion gear ratio. The auto trans buzzed so bad at highway speeds that I sold it after 8 months.
The drone of the exhaust is real. Real annoying.
 
I must be crazy because I actually don’t hate it. Or maybe because it’s my first Jeep I don’t realize how much better life could be. Good tip on the 1” spacers.

Don't worry, the 4.0 is a pretty shitty engine too. It's just that it's a lot better than the 2.5 once you drive both back-to-back.
 
  • Like
Reactions: D M
My DD is a 98 2.5 manual, 4.11 with 31’s. I won’t go any bigger, as I’m at the edge of what I can get away with, with the gearing I have. I don’t have problems using 5th, making it up grades or doing 70 on the interstate. All that having been said, my advice is not to go bigger than what you have now, with the gearing you have and the auto transmission. You won’t be doing yourself any favors.
 
  • Like
Reactions: RyanMkTJ
Hey all,
I've read the many threads, and i know there are a lot out there, please don't hate. I have a 98' with the dreaded 2.5L auto combination, stock 3.73 gears. It currently has 28's on 15x8 wheels. It feels like a death trap above 60 which is a speed I don't exceed. I wan't to put a 31 on the jeep. From what i've read it seems that I can still achieve my cruising speed of 60 with 31's. Also have people had clearance issues at stock height?
I wanted some confirmation before i purchased.
Thanks for answering this for another newb.
You want 31’s? Get’em. Buy a 1” BL or a 1” spacer. Regear and be happy.
 
You'll want a 1" spacer ideally to clear a 31".

You have the worst combo ever put in a TJ however, so even with a 31" it is going to suck big time. However, it probably sucks as it is now (as you've mentioned), so just prepare for it to suck even more.

Re-gearing will help.
As our beloved host said...

This will go from being a slug to a super slug.
You go slow now..it will just be slow...eeeerrrrr if you stay as is.

If you're ok putting an easy to do $2k$ in your Jeep you could track down some factory 4.56 ratio axles from 2003 onward...
 
  • Like
Reactions: RyanMkTJ and Chris
As our beloved host said...

This will go from being a slug to a super slug.
You go slow now..it will just be slow...eeeerrrrr if you stay as is.

If you're ok putting an easy to do $2k$ in your Jeep you could track down some factory 4.56 ratio axles from 2003 onward...
I don’t know if it’s worth 2k$ to make a slow Jeep slightly less slow. I’ve found some found 31’s that are a actually a 30.5 and weight 42lbs. I think this might help a slightly
 
My ‘97 is a 2.5L auto running 3.73 gears and I’m running 33x12.5x15 and I’m perfectly happy... maybe it’s because I’ve never had a jeep with a 6 cylinder or maybe it’s because when I drive it I’m not planning on being in a hurry... I just came back from my first trip in it to the Ozark mountains and there were a few times on steep grades that I had to pull over and let cars go by that were in a bigger hurry than me but on down grades and flat land I had no issues... off pavement I haven’t found anything I can’t tackle in 4 LO!
 
My ‘97 is a 2.5L auto running 3.73 gears and I’m running 33x12.5x15 and I’m perfectly happy... maybe it’s because I’ve never had a jeep with a 6 cylinder or maybe it’s because when I drive it I’m not planning on being in a hurry... I just came back from my first trip in it to the Ozark mountains and there were a few times on steep grades that I had to pull over and let cars go by that were in a bigger hurry than me but on down grades and flat land I had no issues... off pavement I haven’t found anything I can’t
Thanks for the reply! Nice to have info from someone with the same setup. Slow and easy is how I drive already. You’re a brave guy running 33’s. I salute that.
 
  • Like
Reactions: 97JadeTJ