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XJ needs new shoes


NAXJA Forum User
Hey y'all.
I know there are a million tire threads on a million sites.
I was just curious if any one here has personal experience with going from 235s to 31s.
99 XJ
AW4 with Dana 30 up front and Dana 35 w/3.55 in rear with factory LSD.
Lift: mild 2.5"
I have test fit 31s on one side front and rear to check clearances. And I'm good even at full lock. (barely, but good).
I have a couple questions/concerns.
To me with the lift, 235s seem ok size-wize, but the 31s look great.
1. in the rear, makes me think I may need to go with 31x9.5 instead of 31x10.5 as where it sits, there's a seam that runs vertically across the body behind the rear tire in the wheel well.
I think the 10.5 may be a bit too wide and that if I get more than a couple of inches in articulation that I may risk hitting the sidewall against that seam. It's probably a spot welded and sealed one and don't want to compromise it by banging it flat and it end up causing a leak or something.
Last thing I want to do is slice the sidewall on or off road.

2. is going up to a 31 going to cause it to be more of a dog with the stock gearing?

Do I think the 31s look great with the lift?... yes.
I do not want form over function though... so if I'm over thinking it and it really isn't worth it to go bigger than 235s then so be it.
My '98 came on 31"'s with a 2" lift.

The left front tyre just touched the LCA on full left lock, largely eliminated by adjusting the RH stop but disappeared when I fitted 7 1/2" aftermarket rims with a slightly different backspace. On the other hand, when fully flexed the rear tyres have removed the paint from about 1" of the leading edge of the bumper corners (no rear antisway bar), but they are only just within the fender flares.

Still perfectly usable (even on mild/moderate trails) but not so relaxed on the highway as my '99 on stock 235's (but a 2" lift) & noticeably worse fuel mileage (even more so compared with my '96, stock but for the 235's. (OEM onthat were 225's).
I figured that mpg's would drop a bit with 31s. And she doesn't do great as it is. At least not in big city traffic.
As much as I'd love a slightly larger set of tyres....the cons may add up to not being worth it.
I think 31s fill the wells nicely with my 2.5" lift. Doesn't look too big.
But 235s aren't that bad either and can get them a lot cheaper than the 31s
I've had 31's 6 ply 10.5 on a 4.5 lift and 3.55 gearing (doggish) and then 4.10's peppy. Probably 17 mpg hiway.
Presently, I have 31's 10 ply with 9.5 on a 2" lift and 3.73 gearing and 17.5 to 18.5 highway. Both have 2.5 exhuast and bored TB and 99+ horseshoe intake.
Both have WJ big brake. On the 2" I do have a tight fit or clearance from the tire to the swaybar post. I used Ironmans due to OTK setup. I am working on adjustable steering stops for the WJ like the Xjs stock knuckles.
I did exppect a bit better MPG on the 2" lift. I think the 10 plys (E) hurt a bit. Still, other factors.
I had considered the 31x9.5.... that might just get me the clearance I'm looking for especially in the rear with that body seam.
And would give me a little more space from the LCA's up front too. Probably not much weight savings over the 10.5.
if function is more important than form... then get better lockers front and rear& forget bigger tires.
if function is more important than form then get good skidplates instead of worrying about ground clearance.
if function is more important than form add really strong recovery points (AKA "D" rings) and forget about a winch.
I know, I know this is really boring but you know I am right!
Old TJ takeoff 245/75r16 look pretty cool and don’t feel too doggy on a high mile 1989.

Remember that your speedometer will be about 10% off so you need to mentally adjust your speed or it is possible to change the speedo gear on the transfer case.
My Winter tyres are 245's (or maybe 265's*) - anyway I remember the shop reckoned they wouldn't fit, even though they were (a little) small than the 31" MT's they were swapping over to other rims at the same time. With a 2" lift, & on OE wheels, they look just right & that being, maybe a size, smaller than the MT's mean they don't rub at all.

* sorry to be so vague but not seen them for a while - & they're 220 miles away, so can't run outside & check ;)
245/75r16 is working well on the current Jeep with ~2.5in lift. When I most recently replaced them I had a hard time finding that size not in 10-ply. Toyo Opencountry AT was pretty much my only option in 6-ply but I am happy with them.

I had 265/75r16 on the last Jeep with stock gears and 3.5-4 inches of lift and drove it from Maine to Moab a couple times, current tires are better on the highway and I've driven Maine to Death-Valley with this setup.