Different sized tires on a Jeep 4X4?

[ryan2022]

hi guys,

I'm looking into buying a set of tires for my Jeep wrangler.

I've got a decent set of BFG Long Trails right now, but Ive got a line on a set of either Mud King radials, or Hercules M/T's for pretty cheap.

My question is, If the tires have worn slightly differently, due to poor alignment or lack of rotations, would it be bad to put on a 4X4? I have a limited slip in the rear end, and wouldnt want to burn up the clutches due to tires that are different heights, let alone strain the differentials.

Any thoughts? I know I could put the closest two in the back, but that would sort of limited any rotation I could do.

Should I just stick with the BFG's I have now? Honestly, there a terrific tire, I was just hoping for a little more aggressive tire.

Thanks

 

[Chris142]

No 2 tires are exactly the same size anyway. I'd put the closest matching 2 on the rear.

 

[Zaedock]

Originally Posted By: Chris142
No 2 tires are exactly the same size anyway. I'd put the closest matching 2 on the rear.


X2.

 

[440Magnum]

Originally Posted By: Zaedock
Originally Posted By: Chris142
No 2 tires are exactly the same size anyway. I'd put the closest matching 2 on the rear.


X2.


X3, and depending on which transfer case you have, be extra aware of binding in 4x4 mode. If you've got a "full time" transfer case, the differential in it will take care of the different speed of the front axle. If you have "part time" then even going in a straight line the drivetrain will tend to bind with different size tires on the front. Just don't use 4x4 on pavement and you're OK.

I don't *think* they ever used this transfer case in Wranglers, but if you have one of the ones that has a limited slip full-time mode (I can't remember which NP box it is- not the NP231 or NP242- but it was used a lot in Grand Cherokees) then you really need all 4 wheels to be the same size or you'll overheat the center LS unit.

 

[ryan2022]

Thanks for the replies guys./ No LSD in the T case. I THINK its the NP123.

I dont ever use 4x4 on dry pavement anyway, I was more concerned about the diffs, mainly the rear with the LSD.

So you think its okay? Well....I may be in for a nasty looking cheap set of mudders. LOL.

 

[RageOfFury]

You will likely get issues when trying to engage/disengage the T-case because of the different tires. On a 4x4 vehicle you always want to have the same size/make/model/tread life tires. Even a slight difference in tire pressure will cause the T-case not to engage/disengage.

 

[Zaedock]

Originally Posted By: ryan2022
I THINK its the NP123.


It's an NV (New Venture)231, formerly called NP(New Process)231.


Originally Posted By: RageOfFury
You will likely get issues when trying to engage/disengage the T-case because of the different tires. On a 4x4 vehicle you always want to have the same size/make/model/tread life tires. Even a slight difference in tire pressure will cause the T-case not to engage/disengage.


Make and model won't make much of a difference. As long as the size is equal and the treadwear similar. You could even compensate different treadwear by changing the psi slightly on the "taller" tires if you really wanted to. My '89 XJ has a Michelin and Uniroyal on the front and generic AT's on the back. It drives perfectly fine.

FWIW, I've been Jeepin' for a very long time and have never had an issue engaging 4WD due to different tires or slightly different pressures. Between the transmission, t-case, and axles (especially with open/limited slips), there is enough slop in the drivetrain to offer easy engagement.

 

[pavelow]

It's a known fact that you are not supposed to run different sized tires front to rear on a 4WD vehicle *UNLESS* you run different gear ratios front and rear to compensate-like competition mud boggers do when they run 44s in the rear and 35s up front. Granted, there's probably a size up/down fudge factor there in most production 4x4s, but I wouldn't push my luck with anything larger than a size up/down. You run the very real chance of grenading the transfer case when in 4WD otherwise. The reason is the front and rear driveshafts are essentially locked inside the transfer case when in 4WD, so they need to spin the same speed......if you have small tires up front and big ones in the rear or vice versa, the driveshafts are going to want to spin at different speeds. The non-differential equipped transfer case isn't very tolerant of that.

 

[kkreit01]

It sounds like the M/T tires are used? If so, I'd drive on your H/T tires until worn, and then replace with new M/T tires (if that's what you desire).

 

[tomcat27]

other than putting similar size on the rear (due to your trac lock) none of it matter until you engage 4wd. do you? on road? off road? if you are off road in mud or really rough terrain there's so much wheel spin happening anyway - I wouldn't worry. never heard of a transfer case failing to engage or disensgage due to pressure, tires, etc. (except the electronic fords) expecially a 231. just ram it in or ram it out! I've been wheelin since 1990: comanche, cj's, grands, libs. H2. in some really rough stuff in KY, MI, SC. lots of fun! never a prob with a transfer case getting finicky.

 

[Chris142]

I've got 2 well worn tires on the front of my Wrangler and 2 new ones on the rear. No problem at all shifting to 4wd or to 2wd.

I could see a problem if it was 31's on one end and 33's on the other but the 1/2 inch difference between new and worn is a non issue with a Wrangler transfercase.

 

[wannafbody]

Originally Posted By: RageOfFury
You will likely get issues when trying to engage/disengage the T-case because of the different tires. On a 4x4 vehicle you always want to have the same size/make/model/tread life tires. Even a slight difference in tire pressure will cause the T-case not to engage/disengage.


While manufacurers will reccomend the same size and tread on all 4 many manufacturers will spec a different tire pressure. GM has 45 front and 80 rear on 3/4 and 1 ton pickups.

 

[HWEaton]

Originally Posted By: wannafbody
Originally Posted By: RageOfFury
You will likely get issues when trying to engage/disengage the T-case because of the different tires. On a 4x4 vehicle you always want to have the same size/make/model/tread life tires. Even a slight difference in tire pressure will cause the T-case not to engage/disengage.


While manufacurers will reccomend the same size and tread on all 4 many manufacturers will spec a different tire pressure. GM has 45 front and 80 rear on 3/4 and 1 ton pickups.


I think you mean 55 front...