Let's talk 37s on a JLU Diesel

[Compression-Ignition]

My wife's JLURD was a little over an inch taller in the front than the rear. The shocks are the same length. 26" rear & 23.75" front. Could be valved a little different, but I don't know. I suspect the swaybar links are different, based on the fact that the ones I got in my cheap teraflex 2.5 spacer kit seemed way off. I put the ones they sent for the front on the rear and didn't use their fronts. Then I used the factory rears in the front (after some redneck engineering).

I cut the front spacers down an inch so the nose of the Jeep wouldn't be pointing at the sky. The Jeep is still a little nose high.

I don't think that backspace will work all that great stuffed. Clearances get real tight with the 37's so you need to be ready to hack some stuff or your bump stop game better be really really on point.

We don't have the extra weight of a winch up front, but the 5th 37 and wheel hadn't showed up yet either. And you can tell it's still a little higher in the front. The teraflex kit said it was a 2.5", but it came with a 3" front and 2.5" rear. Hence why I cut the fronts down.

It rides pretty good. Waiting on new shocks and steering stabilizer. The factory shocks definitely can't handle the extra weight of this combo.

Sponsored

 

[Gawdly]

I stopped at a dealer today and measured a gas JLU Rubicon. It was in fact 1.25” lower in the front than my diesel, so that rumor is true.

 

[Gawdly]

Compression-Ignition,
Thanks for the info, great to hear from someone who has done this dance with the Diesel. So only the front was taller than a gas rig in your experience? I didn't think to measure the rear when I went by the dealership this morning. Love your rig by the way!

Take a look at Brian0128's post on the previous page. He claims (with photos) that the AEV backspace works and stuffs great with 2" lift. My previous experiences lead me to believe that AEV is on the right track. Lots of backspace will likely be the best bet for steering clearance up front with minimal lift. The further out the wheel sits, the wider the steering arc. There is less wheel well room further away from the pivot point to accommodate that wider arch. Also, vertical wheel travel moves in an arc. With less backspace, the tire travels up further at its outermost point. But counter point says what stuffs best depends on where your room is, in-board or out-board in the wheel well. Guess the easiest answer is pick a wheel and see where it hits.

Usually the guys that spend the time and money to do it different are on to something. AEV's backspace is unique and they claim purpose designed for 2.5" lift on a JL. But I've been wrong before... We'll see.

 

[OnlyOne]

Compression-Ignition,
Thanks for the info, great to hear from someone who has done this dance with the Diesel. So only the front was taller than a gas rig in your experience? I didn't think to measure the rear when I went by the dealership this morning. Love your rig by the way!

Take a look at Brian0128's post on the previous page. He claims (with photos) that the AEV backspace works and stuffs great with 2" lift. My previous experiences lead me to believe that AEV is on the right track. Lots of backspace will likely be the best bet for steering clearance up front with minimal lift. The further out the wheel sits, the wider the steering arc. There is less wheel well room further away from the pivot point to accommodate that wider arch. Also, vertical wheel travel moves in an arc. With less backspace, the tire travels up further at its outermost point. But counter point says what stuffs best depends on where your room is, in-board or out-board in the wheel well. Guess the easiest answer is pick a wheel and see where it hits.

Usually the guys that spend the time and money to do it different are on to something. AEV's backspace is unique and they claim purpose designed for 2.5" lift on a JL. But I've been wrong before... We'll see.

This is 37s stuffed with the mopar lift and factory wheels. No spacers. They will stuff just fine. As I said before, adjust your steering stops to match. The Rubi axles are wider and provide more than enough turning radius to the point you’ll never notice the change. It takes a little fine tuning here and there but it can be done easily with factory wheels, let alone with AEV backspacing. I like my tires tucked under the flares to keep a lot of that winter sling out.

 

[Jamrock]

Casey out of Canada has a vlog series on his 2020 Diesel Rubicon. He put 37's on it without a lift. Lots of unexpected differences between the gas Rubicons and the diesel ones.

Some of the mods that work on the gas vehicles won't work on the diesel.

 

[Gawdly]

Thanks for the photos Only One. Seeing a JL stuffing 37s on stock wheels helps affirm my suspicion that more backspace is the way to go. Good tip on the steering stops.

Jamrock, thanks for the video, went and watch a bunch of his stuff. Was really informative on diesel unique suspension features. Appears the extra 1.25" front height is for suspension to engine clearance and uptravel is limited by the same amount (longer jounce tubes). In my mind that translates to "A diesel won't stuff as far so front clearance for 37s should be less of an issue". The wheel he uses is 0 offset, I think he said 4.75" backspace, a full inch less backspace than the AEV wheels. You can see in one of his vids he is contacting the rear outer fender lip pretty solid flexed. Set the wheel an inch further inboard and I bet it doesn't contact (at least right there).

 

[BearcatMLA]

Good looking rigs! This thread has me re-thinking the direction I was taking with my 3.0 diesel. I went with the Sport S package since I don't live in an area with the extreme rock climbing and was planning on changing the suspension out anyways. My local 4WD shop has me leaning towards the 37x13.5x20s with a 4" super lift and King shocks. After seeing the photos here and little to no lifts being done on your Rubicons it has me wondering if the 4" lift is a mistake. My Jeep is just a second vehicle for around town fun driving and probably wont see 3-4k miles a year.

When do you plan to put the 37s on Gawdly?

 

[Gawdly]

Good looking rigs! This thread has me re-thinking the direction I was taking with my 3.0 diesel. I went with the Sport S package since I don't live in an area with the extreme rock climbing and was planning on changing the suspension out anyways. My local 4WD shop has me leaning towards the 37x13.5x20s with a 4" super lift and King shocks. After seeing the photos here and little to no lifts being done on your Rubicons it has me wondering if the 4" lift is a mistake. My Jeep is just a second vehicle for around town fun driving and probably wont see 3-4k miles a year.

When do you plan to put the 37s on Gawdly?

Have to get my 2012 JKUR sold first, then it’s time for the 37s.

 

[TCogs1]

My 37s on stock, JLR3.6l, rims 100% rub in the front when flexing and I'm not talking about full lock. You will need to swap out bump stops for adjustable ones if you care about rubbing at all.

PS: Even with a Mopar Lift I still rub in the front.

Running Pats 37x12.5x17.

hmm .. I have a similar setup, running Mopar 2", 37" v 12.5 Maxxis with Methods 101 (4.5 back space) bead locks, Zero rub on Dusy, Rubicon etc trails.. I am experimenting with Treps which are 13.5 wide.. let you know soon.. I agree with the other posters, Stick with stock and 35's at the most or you will pay the price at the pump, my MPG drops from 17 to 13 on the highway when i swap my stock street tires with my stickies (Maxxis), meaning I trailer my tires to the trail head if I know i am going to do a tough trail, it takes 30 min to swap, but save a lot of $.

On a side note, I added the airsprings in the rear, designed for a RAM 1500, best $100 bucks i ever spent, allows me to level when i have a heavy load and or know i am going to really be stuffing the rear, 25psi and an instant 2" additional lift..

hope that helps,

TC

Sponsored