37s on stock 392?

[delbuort]

Ok, I tired to search, but looking for a thread with 37" tires in it on here is kinda like looking for ice cream at Baskin Robins. Don't roast me too much if this has been asked 800 times (sorry, lol). Besides...this is my first post here.

Got a "new to me" 392. 2021 with just over 11k miles. I've had him (decided on naming him Papa Smurf) out on the trails a couple weekends now (freakin' beast, by the way). I'd like to put 37s on there. Will they fit the stock 392 without a lift? Got a friend that said the 392 has a 2" lift stock and should work fine. I'm not sure about that. Thoughts?

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[Mocopo]

Not a 392 owner here, but to ask an important bit of info... Do you have the XR package?

 

[delbuort]

I don’t believe so. I’ve got the build sheet and it doesn’t say anything about it. It says it came with LT285/70R17C BSW M/T tires and 3.73 gears. I believe the XR package came with LT315/70R17C tires and 4.56 gears.

 

[stumblinhorse]

They will fit with or without the XR package. They are the same lift. Only thing is 37s will rub more on a 392 vs one with the XR package because the XR package has huge bump stops. If you add a little bumps stop it won’t rub.

 

[Punkindug]

They will fit with or without the XR package. They are the same lift. Only thing is 37s will rub more on a 392 vs one with the XR package because the XR package has huge bump stops. If you add a little bumps stop it won’t rub.

Any experience on what or which bump stops to add?

 

[Fast-n-Furious]

This video should give you more details:

In short, with no additional lift, the rear will rub, and adding some landing pad should solve the issue. You may sacrifice the up travel as a result.

 

[3TV]

On my 392 XR I had to extend the rear bumpstops 1", which now prevents all but the slightest of tire contact with the inner fender liner at full stuff. On your 392 you will need to extend the front bumpstop to the same length of a 392 XR to prevent tire contact. Take a look under your Jeep and see how much up travel you will have with the extended bumpstops. If you don't think that is enough then it is time for a suspension lift. Or if you find that you are contacting the bumpstops too often after they are extended then you can do a suspension lift at that point.

I put 37s on mine with stock suspension to begin with, and tolerated the rear tire rub for a bit. Then I added 1" spring spacers and extended the rear bumpstops an inch, which actually worked well. I did not like the look of my 392 XR with 37" tires and stock suspension, or 1" spring spacers. It looked like someone had lowered my Jeep, or had tried to stuff tires that were too big on to it. I also still tended to scrape the belly in a few places off road. So then I just went to a 2.5" suspension lift. It works better off road, and although I didn't extend the rear bumpstops anymore than before, the very minimal tire rub on the back end rarely occurs any more. Usualy only 1 time for a day of serious four wheeling. For less serious trail rides the rear tires never contact the plastic liners. I'm happy with it now, and would advise just going to a 2 1/2" lift and getting it over with.

I noticed a slight decrease in power going from 35s to 37s with 4.56 gears. You will also notice a difference going from 33s to 37s with 3.73 gears. For me the difference was only noticable for a day or so, and now it just feels normal. And normal is pretty good with a 392.

 

[delbuort]

Great info. It came with 35s when I got it. The person before me put on some Fuel Covert D696 (I think that’s what they are) rims. I think they have a 20mm offset. Unfortunately, I think the rings are just a facade and aren’t actually functional.

I’ve been looking at a 2.5” lift kit already, a friend pointed me to. I’m certainly not opposed to it, just didn’t want to put it on if it already has a lift the same height. Seems counterproductive on that one.

 

[2nd 392]

On my 392 XR I had to extend the rear bumpstops 1", which now prevents all but the slightest of tire contact with the inner fender liner at full stuff. On your 392 you will need to extend the front bumpstop to the same length of a 392 XR to prevent tire contact. Take a look under your Jeep and see how much up travel you will have with the extended bumpstops. If you don't think that is enough then it is time for a suspension lift. Or if you find that you are contacting the bumpstops too often after they are extended then you can do a suspension lift at that point.

I put 37s on mine with stock suspension to begin with, and tolerated the rear tire rub for a bit. Then I added 1" spring spacers and extended the rear bumpstops an inch, which actually worked well. I did not like the look of my 392 XR with 37" tires and stock suspension, or 1" spring spacers. It looked like someone had lowered my Jeep, or had tried to stuff tires that were too big on to it. I also still tended to scrape the belly in a few places off road. So then I just went to a 2.5" suspension lift. It works better off road, and although I didn't extend the rear bumpstops anymore than before, the very minimal tire rub on the back end rarely occurs any more. Usualy only 1 time for a day of serious four wheeling. For less serious trail rides the rear tires never contact the plastic liners. I'm happy with it now, and would advise just going to a 2 1/2" lift and getting it over with.

I noticed a slight decrease in power going from 35s to 37s with 4.56 gears. You will also notice a difference going from 33s to 37s with 3.73 gears. For me the difference was only noticable for a day or so, and now it just feels normal. And normal is pretty good with a 392.

I lost a half step going to light 35’s with 3.73’s. 4.56’s gained a full step and sufficient for 37’s. 4.88’s would have cost the same. Would have if I wanted 37’s.

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