37" tires. What is breaking?

[camprats]

We belong to to that minority of owners who use their Jeeps very hard on a regular basis. We go a few times a week, almost every every week, all year long in support of our Jeep trail website JeeptheUSA.com. We do everything from Forest Service roads through “normal” Jeep trails, up to somewhat difficult rock crawling. Think Metal Masher in Moab or Chinaman Gulch in Buena Vista.

We will be putting on a 3.5” MetalCloak lift, Rock Hard aluminum bellypan, RPM front and rear bumpers with tire carrier and ADS racing shocks. Now trying to decide if we want to put on 37” tires immediately, or wait to see what other people have for problems so we can do something to prevent them from happening to us.

37” tires will put a lot of stress on components that are not designed for it. This may not be significant to people that put them on for appearance on the highway, but it surely will be to people like us. Jeep trails all over the West are getting rockier, bumpier and more difficult every year. Heavier traffic from buggies, Jeeps, quads and side by sides is taking a toll. We really want to put 37s on our 4-door JL Rubicon to make these trails more comfortable and easier to drive, but are reluctant to do it until we learn what has to be made stronger to support the larger tires. We speak from painful, and expensive, experience with a previous 4-door JK with 37s. I realize things have been redesigned on the JL, but...

Please chime in with what you have actually broken, as well as opinions on what is vulnerable to breaking. We will be watching this thread.

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[Scottroxxx]

components that are not designed for it. .

Says who? The Mopar performance parts catalog says you can put 37's on the Rubicon With a 2.5" lift. Just have to keep in mind the Jeep is "trail rated" not "rock rated".

 

[American Jeeper]

Nothing yet but my wallet! I only have about four days of hard enough wheeling that I feel has stressed things to the point where something would eventually bend or break, and so far everything looks good. It will be interesting to see who has had 37’s (or bigger) on the longest and has wheeled the hardest in their JL and what does give. The front axle tube and C’s still can bend over time I think, although my JKUR stock axles held up fine with 35’s and the Mopar lift. Time will tell.

 

[W5MQS]

Says who? The Mopar performance parts catalog says you can put 37's on the Rubicon Wirth a 2.5" lift. Just have to keep in mind the Jeep is "trail rated" not "rock rated".

I agree with what @Scottroxxx says. The Rubicon is the...for a lack of better terms...the "heavier duty" version of the Wrangler line. 37" tires shouldn't be that big of a deal.

 

[VolCntry73]

I believe @Kevin8086 would have the best insight on this. I would wager that no one on this forum does any more harder wheeling than they do on a virtually stock setup with larger tires. Unless they have changed, they are wheeling on 38's.

 

[Jeepsk8]

There is a thread going where a tie rod broke. Looks like he's on 37's.

 

[camprats]

There is a thread going where a tie rod broke. Looks like he's on 37's.

I assumed he hit a rock/ledge. If not, that would be a major problem.

I asked him if he hit a rock in the original post. Hope he answers. https://www.jlwranglerforums.com/forum/threads/jl-tierod-is-a-joke-thanks-jeep-engineers.14171/

UPDATE: He did answer. He did not hit a rock. This is definitely a problem.

 

[Nikolay Bakalov]

Hey guys, I'm brand new participating in the forum but been following for a long time. Anyone still following this thread? I'd love to hear someone with experience chime in on "What needs to be reinforced/upgraded before breaking or too quickly wearing off parts with 37s on JLUR?" It's been 2 years now, there should be some good common info.

After some research I've decided on a Metalcloak 2,5 GC with rocksport shocks and an aftermarket driveshaft.
I'm thinking 37 inch 12.5 cooper stt pros on stock wheels. Does all this sound like a good setup to you guys and would the stock parts hold well for a long time on frequent hunting trips up the mountain and some rock crawling here and there?
Thanks!!!

 

[Qjoh5510]

Better off assuming all the same things as a jk should be upgraded. Truss, gussets, ball joints, shafts, steering, and so on. Only thing new would be the fad on the axle housing.

 

[wibornz]

We have 5 JLURs that run 37s. We have wheeled all over the country with no issues other than one JLUR alternator craping out. We have completed 32 badge trails in just over one year. Including all the badges in Colorado, Utah, the Rubicon Trail in California, done Windrock twice, Rousch Creek and Uwharrie + many more. We drive and tow campers to all the wheeling trips.

I forgot, I did twist one of the axle shafts. Probably on the Rubicon Trail. It did get me home from California to Montana and back to Michigan.

We wheel hard and have done difficult trails, like Holy Cross, Rubicon, Pritchet Canyon, Poison Spyder, Crawl Daddy, trail 16 at Windrock and many others.

Between our 5 JLURs that we wheel, we have a combined total mileage of over 150,000 miles on 37 inch tires.

 

[bigfoot21075]

We have 5 JLURs that run 37s. We have wheeled all over the country with no issues other than one JLUR alternator craping out. We have completed 32 badge trails in just over one year. Including all the badges in Colorado, Utah, the Rubicon Trail in California, done Windrock twice, Rousch Creek and Uwharrie + many more. We drive and tow campers to all the wheeling trips.

I forgot, I did twist one of the axle shafts. Probably on the Rubicon Trail. It did get me home from California to Montana and back to Michigan.

We wheel hard and have done difficult trails, like Holy Cross, Rubicon, Pritchet Canyon, Poison Spyder, Crawl Daddy, trail 16 at Windrock and many others.

Between our 5 JLURs that we wheel, we have a combined total mileage of over 150,000 miles on 37 inch tires.

THANKS for the post! Fantastic! I need to step up my game and head beyond the east coast!

 

[chevymitchell]

We have 5 JLURs that run 37s. We have wheeled all over the country with no issues other than one JLUR alternator craping out. We have completed 32 badge trails in just over one year. Including all the badges in Colorado, Utah, the Rubicon Trail in California, done Windrock twice, Rousch Creek and Uwharrie + many more. We drive and tow campers to all the wheeling trips.

I forgot, I did twist one of the axle shafts. Probably on the Rubicon Trail. It did get me home from California to Montana and back to Michigan.

We wheel hard and have done difficult trails, like Holy Cross, Rubicon, Pritchet Canyon, Poison Spyder, Crawl Daddy, trail 16 at Windrock and many others.

Between our 5 JLURs that we wheel, we have a combined total mileage of over 150,000 miles on 37 inch tires.

I'm on my second JL with 37's and have also wheeled dozens and dozens of trails and wheeled hard all across the country on 3 separate trips over the last 3 years. I have not broke anything either. The Jeep held up great. On my second JL here, I won't be upgrading a lot of components until I run into an issue.

I will say that both of the factory rear axle shafts were twisted on Fat Ninja and was found when we were doing the axle sensor inspection once the locker light thing started happening. @mgroeger

Mike - Did you have pictures of those axles shafts?

OP - Other than that, wheel smart and you and the Jeep will do great on 37's.

 

[chevymitchell]

THANKS for the post! Fantastic! I need to step up my game and head beyond the east coast!

Once you make it out to SMORR and anything West of I-25, you'll be itching to go back. It'll change your perspective of wheeling on the East Coast.

 

[mgroeger]

I'm on my second JL with 37's and have also wheeled dozens and dozens of trails and wheeled hard all across the country on 3 separate trips over the last 3 years. I have not broke anything either. The Jeep held up great. On my second JL here, I won't be upgrading a lot of components until I run into an issue.

I will say that both of the factory rear axle shafts were twisted on Fat Ninja and was found when we were doing the axle sensor inspection once the locker light thing started happening. @mgroeger

Mike - Did you have pictures of those axles shafts?

OP - Other than that, wheel smart and you and the Jeep will do great on 37's.

Unfortunately I don't have any pics. The driver's side was aprox. 3/4's of a spine twisted and was very visible. The passenger side was fine and I actually still have it as a spare. The cost of a Dana chromoly shaft is very reasonable. I think I paid $360 for the pair in the rear.

 

[InvertedLogic]

Rear axle shaft twisting seemed to be an issue with JKs as well. I know two people with JKURs that ran 37s for awhile then switched to 35s and both of them twisted splines and bent the flange where it meets the shaft.

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