Regearing for 37s?

[InsuredbyJeepinJessica]

With 22's it's obviously not going to spend time off road so your gearing probably is fine for cruising around, etc, etc.

It’ll definitely go off-road occasionally but no rock climbing or anything like that. Went with a 10” wide wheel on a 13.5 wide tire to have some sidewall protection. Never had an issue with our trucks and 22s getting dirty either...

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[Pig-Pen]

good looking wheels. i think they'd look better in 20" but it doesnt look horrible. not like so many others we've seen on big wheels. those tend to be too flashy. enjoy your ride

 

[ReefGoat]

wow I really like that wheel and tire combo. Looks badass. I wish I had the cash to go with 37s.

 

[GRN JLLO]

Went with 4:88's and replaced the front axles with RCV axles. Also reprogrammed using the Superchips flashcal. The 4:10's were fine around town with the 8 speed and 37's however it would hardly get into 8th gear at interstate speeds. They made a huge difference on the Interstate. I pulled a small trailer with a motorcycle from Socal to Moab 11.5 hrs each way at 80mph no problemo.

 

[mgroeger]

Thanks for the info! I appreciate it!

There is something to note here. He has a Rubi which means he already has the 4.10 gears in it which is why technically he can get away with the jump to 37s all be it rendering 7th and 8th gear useless.
You on the other had do not have a Rubi which means you have 3.54 or 3.73 (can't remember which) gears which means jumping to 37s is going to make your Jeep a DOG and most definitely really jack the speedometer way off. You will notice a definite difference in performance with that set up.
37s go really well with 4.88 gears which the Rubi is one jump away from but you are two jumps away from.
You should also invest in a Tazer so you can program the new tire size (and gears if you get them) so your speedometer and shift points will be correct.

Way to stick up for yourself with those gawd awful 22" rims. I was all set to be a $martass and bust on you but realized it would be fruitless

 

[Unix_Gawd]

Hey everyone,

My husband and I just purchased a 2020 JL Sahara. This Jeep will be driven as a marketing vehicle back and forth from the office and home with an occasional trail ride. We just purchased a 3.5” lift, 22x10 wheels, along with some 37s. I don’t care if you think big wheels suck, you’re not paying for my additions so move along. I’ve heard and seen multiple people talk about regearing or not needing to but would like to hear more...should we or shouldn’t we? Oh, it’s the 2.0L turbo too...

I have 3.5" and 40s with 5.13 Spicer gears and a ProCal to sync the computer. Drives like a stock jeep and shifts great through all 8 gears. Well worth it to re-gear. There is a chart online that shows what gear works best based on tranny, tire size, etc.

BTW, 2.5" will easily allow u to run 37s.

 

[Thexr6]

Nope. My reading comprehension is just fine. But, when you post in a open forum, don’t think you are shielded from other people’s opinions. Plus, the attitude on your first post was a little grating. Enjoy getting laughed at by other Jeepers.

why the hate? we have every right to mod our jeeps whatever way we want. just because I or you won't run 22s, the OP has a legit question and is asking for info, not a critique.

 

[ZombieMojitoJL]

remember you have 4:10 gears a Sahara will quite worse. I think they are 3:73 or high ratio, not numerically.

I’m with UK on the big wheels, I thought it was just a Florida thing.

The Sahara with 2.0T are actually 3.45 for gearing -

 

[UKCATS]

why the hate? we have every right to mod our jeeps whatever way we want. just because I or you won't run 22s, the OP has a legit question and is asking for info, not a critique.

People have the right to do whatever they want, just as I have the right to voice my opinion. Just wait to you hear my opinion on angry grills. #nosafespaces.

 

[mgroeger]

People have the right to do whatever they want, just as I have the right to voice my opinion. Just wait to you hear my opinion on angry grills. #nosafespaces.

 

[Thexr6]

There is something to note here. He has a Rubi which means he already has the 4.10 gears in it which is why technically he can get away with the jump to 37s all be it rendering 7th and 8th gear useless.
You on the other had do not have a Rubi which means you have 3.54 or 3.73 (can't remember which) gears which means jumping to 37s is going to make your Jeep a DOG and most definitely really jack the speedometer way off. You will notice a definite difference in performance with that set up.
37s go really well with 4.88 gears which the Rubi is one jump away from but you are two jumps away from.
You should also invest in a Tazer so you can program the new tire size (and gears if you get them) so your speedometer and shift points will be correct.

Way to stick up for yourself with those gawd awful 22" rims. I was all set to be a $martass and bust on you but realized it would be fruitless

Quick question - JL/Turbo/37s/Auto - stays is 7th gear on highway - 70MPH at 2500 RPM. Manual Shift to 8th gear maintains 70-75 MPH, but drops to 2000 RPM. any harm in doing that? or good reason to re-gear from 4.1 to 4.88? (performance is fine, and Catback/Cold Air prob helps a bit too)

 

[mgroeger]

Quick question - JL/Turbo/37s/Auto - stays is 7th gear on highway - 70MPH at 2500 RPM. Manual Shift to 8th gear maintains 70-75 MPH, but drops to 2000 RPM. any harm in doing that? or good reason to re-gear from 4.1 to 4.88? (performance is fine, and Catback/Cold Air prob helps a bit too)

I'm no expert but we had a similar thing: We have the Sahara 3.6L/Auto with 3.54 or 3.73 gears (I don't recall which) and we had 33s (the factory tire was more like a 32) on it and the only time we would see 8th gear was at 75mph cruising barely touching the gas on long flat open highway and then I'd be at like 1800rpms.
When we put Dana 44s on it we got the 4.10 gears which is what those 33s came from the factory with. I noticed that I'm in 8th gear all the time... at 74 mph on highway or 48 mph cruising down a street not being on the gas.
At 74mph and in 8th gear I'm at around 2100 - 2200 rpms. A friend with a Rubi (which has the 33s and 4.10s) said what I was describing is exactly what he sees with the 3.6/auto.
So, applying that information to your situation, I would make the assumption that getting 4.88s would definitely put you into 8th gear at those speeds which in turn would bring your rpms down some.
I can't see any harm in putting it into 8th manually but if you need to jump on it I would put it back into full auto. The tranny is telling you it's not ready to go there but you can put it there.
Technically you can do anything as people have shown but the reality is if you want to keep that factory shift point and run the engine/tranny at it's optimum range (like designed to do) you really want to re-gear.
Re-gearing is a costly venture (expect $1600-$1800 if done by a pro) which is why many try to avoid it and in turn dump that money somewhere else in the Jeep.
Our take is we want to put the money where we are going to get the best performance both on and off road which is why we will go with 4.88s if the day comes for 37s.
You also need to look at how you will use it. If you are going to mall crawl it you could probably stay with what you have. But, if like us, you want to really wheel it then you want that gearing right AND if you are going to 37s and you wheel it hard you definitely want to beef up your drag link and tie rod.
Hope that helps, I am by no means an expert

 

[Thexr6]

I'm no expert but we had a similar thing: We have the Sahara 3.6L/Auto with 3.54 or 3.73 gears (I don't recall which) and we had 33s (the factory tire was more like a 32) on it and the only time we would see 8th gear was at 75mph cruising barely touching the gas on long flat open highway and then I'd be at like 1800rpms.
When we put Dana 44s on it we got the 4.10 gears which is what those 33s came from the factory with. I noticed that I'm in 8th gear all the time... at 74 mph on highway or 48 mph cruising down a street not being on the gas.
At 74mph and in 8th gear I'm at around 2100 - 2200 rpms. A friend with a Rubi (which has the 33s and 4.10s) said what I was describing is exactly what he sees with the 3.6/auto.
So, applying that information to your situation, I would make the assumption that getting 4.88s would definitely put you into 8th gear at those speeds which in turn would bring your rpms down some.
I can't see any harm in putting it into 8th manually but if you need to jump on it I would put it back into full auto. The tranny is telling you it's not ready to go there but you can put it there.
Technically you can do anything as people have shown but the reality is if you want to keep that factory shift point and run the engine/tranny at it's optimum range (like designed to do) you really want to re-gear.
Re-gearing is a costly venture (expect $1600-$1800 if done by a pro) which is why many try to avoid it and in turn dump that money somewhere else in the Jeep.
Our take is we want to put the money where we are going to get the best performance both on and off road which is why we will go with 4.88s if the day comes for 37s.
You also need to look at how you will use it. If you are going to mall crawl it you could probably stay with what you have. But, if like us, you want to really wheel it then you want that gearing right AND if you are going to 37s and you wheel it hard you definitely want to beef up your drag link and tie rod.
Hope that helps, I am by no means an expert

Thanks! Super helpful!

 

[Elusive YETI]

I have 37s on a 2019 JLUR and changed gears out to 4.88. I am glad I did! Much better acceleration for getting on it without sacrificing a lot of gas mileage. I also pull a 5x8 cargo trailer at times. Average gas mileage is 17 and I live in the foothills. Definitely an upgrade I am glad I made. I believe 5.13 is too much, unless you are doing a lot of rock crawling.

 

[OrangeRuby]

2020 JLUR w 3.6 Here. Daily drive and wheel as much as I can.

Had 37x13.5r17 Cooper STT Pros...drove them for a week, took them off and went with 35x12.5r17 KO2s.

All the engines in the JL have enough power to run them, but even with 4:10s you can hear a definite change in the work the trans is doing. It’s clearly working harder to get those big monsters spinning. Do I think this work will affect the longevity, no? I think it’s just going to hit you in the wallet in terms of MPG. More time at higher RPMs.

I took mine off because I really don’t want to regear it yet. I think it is a must to run the setup right and be happy with it. Your Jeep looks pretty bare in terms of mods. If you intended to add bumpers, winches, racks, armor, etc, it would be essential just because of the load you are putting in the vehicle.

I think it is about your core philosophy of how/why you run your rig. I would never run 22” rims because they don’t have enough sidewall for aired down wheeling. I want my Jeep to be the epitome of dependable and capable wherever I take it. So I make my choices based on that. As long as you’re willing to pay to put gas in it and are happy with the way it drives/sounds/looks, do whatever. I doubt there will be long term mechanical ramifications as direct result of running them.

Just wasn’t for me w/o a regear. They do look amazing though (37s in general, not yours).

Also, you did seem a a bit sensitive about your decision to put 22s on your Jeep. I think pretty much anytime someone has to defend their choices in advance, they are sensitive regarding the subject.

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