Ideal tire size..

[CarbonSteel]

Looks real good.

We need to add steps to the list of modifications needed for the 37's. That way friends and family can actually get into the Jeep.

I fabricated those myself. They have 4 bolts each that attach to the ROAM frame mounts and can be removed pretty easily for hitting the trails. My wife has bionic knees and is only 5'-4" and needs a boost to get in. I find it is easier on me too

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[blnewt]

That way friends and family can actually get into the Jeep.

Friends and Family???
Oh wait, you're talking about a 4 door

 

[Headbarcode]

315/70-17 bfgoodrich ko2's and all else stock...

Same 315's and 2" Dynatrac Endurosport lift (only shot I took before chopping the front fenders)...

38x13.5 Milestar Patagonias with the Dynatrac lift, and chopped fenders (visually from the side, the chop is about an 1.5" difference from the tire)...

Same 38's with a 3.5" Metalcloak Gamechanger...

And added the LOD Destroyers to help my 4'10.75" wife climb in and out. It never gets old, watching her climb. She can just about walk under the side view mirror without hitting her head. ?

 

[Jamrock]

And added the LOD Destroyers to help my 4'10.75" wife climb in and out. It never gets old, watching her climb. She can just about walk under the side view mirror without hitting her head. ?

I have seen some creative solutions for this.

And another cute little thing I did...I made a little rope ladder for,my toddler to climb up into my Jeep. He LOVES it and it’s really cute to watch him!

 

[Headbarcode]

I have seen some creative solutions for this.

Hahahahaha!

My shoulder is still wearing a little fist sized bruise after showing her a similar picture.

This was my suggestion for helping her get out...

 

[Zacreth]

I have tried the 3 most popular sizes:

285/70/17 (Falken Wildpeak M/T LR-C)
315/70/17 (Kanati Trail Hogs AT-4 LR-E)
37x12.5x17 BFG KO2 LR-C)

Subjectively speaking, with a non-lifted Rubicon, 35's are a sweet spot especially with a 2.0T. Fills the wheel wells nicely, still has some articulation room, and if one does not have the 3.6L, the power does not take too much of a hit to make it necessary to re-gear or if you have the 3.6L you have to choose to live with it.

With a lifted "any model", 37's are the way to go, but that comes with a caveat--you are going to have to re-gear and be prepared to change out ball joints, potentially axle shafts, etc. to beef up the drivetrain and suspension.

In the end, it depends on what you are going to do with your Jeep which then determines what you need to modify.

As for me, after trying all 3, the 37 is my favorite of the lot particularly since I added a lift kit, beefed up the front and rear axles, and re-geared to 4.88.

I thought I put this to rest and decided that going 35" would be fine. I test drove one locally that had 37" and it was nice to sit higher and such.

My question now, if I wanted to go 37" why would I need to change out the ball joints, axle shafts, and all the other stuff? I understand the re-gear possibly (BTW getting a 4xe), but do I have to do front and rear axles? Lift is understandable and a possible future re-gear.

Thanks!

 

[Jamrock]

I thought I put this to rest and decided that going 35" would be fine. I test drove one locally that had 37" and it was nice to sit higher and such.

My question now, if I wanted to go 37" why would I need to change out the ball joints, axle shafts, and all the other stuff? I understand the re-gear possibly (BTW getting a 4xe), but do I have to do front and rear axles? Lift is understandable and a possible future re-gear.

Thanks!

It is all about the additional weight of the larger tires.

Much depends on how much stress you will be putting on the vehicle. What kinds of trails will you be driving it on?

There have been reports of components breaking or wearing more quickly when heavier tires, steel bumpers, winches, etc are added. Many of the Rubicon axles become available for sale when the owners start adding after market components to meet the additional demands they will be putting on their Jeeps.

I am not sure if 37's will be an issue but definitely 38's and 40's will add a lot of weight to the Jeep.

 

[CarbonSteel]

I thought I put this to rest and decided that going 35" would be fine. I test drove one locally that had 37" and it was nice to sit higher and such.

My question now, if I wanted to go 37" why would I need to change out the ball joints, axle shafts, and all the other stuff? I understand the re-gear possibly (BTW getting a 4xe), but do I have to do front and rear axles? Lift is understandable and a possible future re-gear.

Thanks!

OEM ball joints have plastic internals and the added stress of larger tires will cause them to wear out faster than they already do.

If off-roading in rocks and the like the OEM axle shafts can begin to twist at the splines and the FAD area is a weak spot in the axle housing and can break.

The OEM tie-rod, drag link, and track bar are made from thin wall tubing with hydraulically crimped ends that will begin to wear at an accelerated rate and/or begin to loosen at the crimps due to the added stress.

All of these items wearing will cause the handling and stability to degrade to the point of issues like death wobble happening.

For clarity, these things will eventually happen anyway with OEM components, but the larger tires simply accelerate the process.

 

[Zacreth]

OEM ball joints have plastic internals and the added stress of larger tires will cause them to wear out faster than they already do.

If off-roading in rocks and the like the OEM axle shafts can begin to twist at the splines and the FAD area is a weak spot in the axle housing and can break.

The OEM tie-rod, drag link, and track bar are made from thin wall tubing with hydraulically crimped ends that will begin to wear at an accelerated rate and/or begin to loosen at the crimps due to the added stress.

All of these items wearing will cause the handling and stability to degrade to the point of issues like death wobble happening.

For clarity, these things will eventually happen anyway with OEM components, but the larger tires simply accelerate the process.

Thanks CarbonSteel!

So if I wanted to pursue the journey to 37" tires, and other than the tires and the lift, what order would you recommend for parts replacement if done on a budget and not go all out where the wife will first divorce me and then kill me to collect life insurance?

 

[GATORB8]

I thought I put this to rest and decided that going 35" would be fine. I test drove one locally that had 37" and it was nice to sit higher and such.

My question now, if I wanted to go 37" why would I need to change out the ball joints, axle shafts, and all the other stuff? I understand the re-gear possibly (BTW getting a 4xe), but do I have to do front and rear axles? Lift is understandable and a possible future re-gear.

Thanks!

We have no issue with power with the 4.10s and 35s. I don’t think you’d be in any rush to regear with 37s.

 

[BlackGenesis]

35" tires and maybe tiny lift (daystar 3/4") spacers will satisfy your offroading needs (as you have described) without any sweat and scraping.

You would be perfectly fine to do all of your offroading in stock condition.

 

[CarbonSteel]

Thanks CarbonSteel!

So if I wanted to pursue the journey to 37" tires, and other than the tires and the lift, what order would you recommend for parts replacement if done on a budget and not go all out where the wife will first divorce me and then kill me to collect life insurance?

If you are going to install a lift kit, the majority of the parts are in it such as front trackbar - prime culprit for death wobble, tie-rod, and draglink.

I would wait on the ball joints until they are an issue. If not doing any heavy off-roading, you are likely good on the axle shafts, trusses, gussets until the point that you are looking to re-gear at which point it makes economical sense to do those at that time.

 

[Some Random Guy]

Thanks CarbonSteel!

So if I wanted to pursue the journey to 37" tires, and other than the tires and the lift, what order would you recommend for parts replacement if done on a budget and not go all out where the wife will first divorce me and then kill me to collect life insurance?

Just have a rainy day fund so that you can replace things as they wear out. No need to do it all up front unless you have money to blow.
I’m on 39’s with the stock axles and enjoying it. I just don’t bump over things, I find another line. My logic is if I need to bump on 39’s, I’d have no business doing that line on 37’s, so my axle shouldn’t be put under that stress.
35’s are a sweet spot of capability for the cost, don’t feel bad about sticking with them. You’re only missing out on extra costs with 37+. Like trimming the rear body for anything over 37”.

 

[guarnibl]

As others have said, it really depends on what trails you are running. Can you give us some examples? What is your experience with four wheeling?

I think others have given general advice, which is fine -- but one thing that I didn't do when I bought my first Jeep that I should have, was simply just go use it and figure out what was needed, instead of the other way around.

The stock Rubi is pretty damn stout from the factory, and what you will need to upgrade to make it confidently through trails will depend on experience and trail difficulty. That could vary from nothing to a lot. I wheeled my '19 JLUR bone stock (no lift, 33" KO2 tires) through most of Moab's trails before upgrading it, even some 7's. While I used the skids here/there, that's kind of the point of having them.

 

[The Last Cowboy]

With 37s, and to some degree 35s with aggressively, offset wheels it not just weight but leverage too. The OEM components were designed and engineered to function under certain perimeters with a certain tolerance for occasionally dynamically exceed them. Many people who primarily drive on the street or beach may never have problems. But add the stress of climbing some rocks, negotiating steep and twist rutted roads or miles upon miles of unimproved washboard roads and you will quickly find the weakness in the ball joints, yokes, etc.

Do they all need to be replaced and fixed right away? No, unless you intend extreme use from the start. But some of the these items will disable your Jeep when they break. Others, like the ball joints will leave you with a bad vibration or death wobble.

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