37's on a Rubicon...

[lowmpg]

I'm sure I'll get the "use the search" response, but I did and didn't find a definitive answer. If I put 37x12.5x17's on my 2021 Rubicon, do I need to regear or not? I'm thinking "no" that 4.11's are fine and 4.88's are better, but I just want to know is regearing an immediate need if going from 35's to 37s?

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[zrickety]

I know a guy locally on 37's...he did not regear, seems pretty happy with it.

 

[bacon392]

I had a gladiator on 37s. To be honest, the 8 speed auto is pretty forgiving, but if you want to regain 8th gear, then moving to 4.56 or 4.88 would be optimal. I did re-gear to 4.88, but only because I was towing a 6400# travel trailer. If not for that, I'd have just stayed with 4.10.

 

[19 JLUR Bright Whit3]

I'm sure I'll get the "use the search" response, but I did and didn't find a definitive answer. If I put 37x12.5x17's on my 2021 Rubicon, do I need to regear or not? I'm thinking "no" that 4.11's are fine and 4.88's are better, but I just want to know is regearing an immediate need if going from 35's to 37s?

I'm thinking you already know the answer. Yes, you "wont NEED" to regear with 37s, but I noticed I never was in 8th gear long. After going to 4:88, I'm living in 8th on the highway and back to almost stock shifting points. My .02 PS. Some folks like their 5:13s for towing and final gear ratios off-road.

 

[lowmpg]

Thanks all! I'm not super pressed on 8th gear, though I will plan to regear later. Appreciate the responses. I'm planning on moving out from my 35 WildPeak MTs to a 37 K02 setup this spring, then I'll just sell the Wildpeaks.

 

[lowmpg]

I'm thinking you already know the answer. Yes, you "wont NEED" to regear with 37s, but I noticed I never was in 8th gear long. After going to 4:88, I'm living in 8th on the highway and back to almost stock shifting points. My .02 PS. Some folks like their 5:13s for towing and final gear ratios off-road.

Did you put the 4.88s in yourself? Mind sharing what the total damage cost wise was and what gear brand you went with?

 

[word302]

Did you put the 4.88s in yourself? Mind sharing what the total damage cost wise was and what gear brand you went with?

You’re looking at roughly $1000 in parts. Get Dana Spicer gears and install kits.

 

[Jhawth]

I just recently put KO2 37s w/ KMC machete beadlocks on my rubi. Do you need to regear? No, you don't need to. Do I want to regear? Sometimes I do, but 95%+ of the time I am totally fine with not regearing. Honestly the only time I feel like I need to regear is on long highway trips with a head wind. When I'm wheeling I don't feel like I'm at a disadvantage with the 4.10s, and then when I put it in 4 low I can't even tell I'm on 37s. Where I live is mostly flat too so I'm not affected as much as someone who lives in the mountains, where I could see regearing potentially being more relevant.

 

[Jerrod20]

I am running 37" BFG KM3's without a regear and honestly on the road I don't notice a huge difference. I do have a TazerJL and changed the tire size appropriately (actually measure your tires ground to top). I am sure a regear would make a difference but using it as a pavement princess I do not think its a requirement by any means. Now if you plan to wheel it, especially if you will be rock crawling in any sense, then it may be a different story.

 

[micahpop]

I'm sure I'll get the "use the search" response, but I did and didn't find a definitive answer.

Because there's no such thing... by my calculations, it's pretty evenly split between the "you won't even notice you have 37's" group and the "only fools and tightwads don't regear" group.

I don't have 37's yet but I'm hoping to be in the first group soon.

 

[Adv_aw8s]

I'm in the diesel crowd and I did not regear with 37's and it cruises through the Rockies no problem. If and when we get an off road trailer I'll probably go to 4.56's

 

[19 JLUR Bright Whit3]

Did you put the 4.88s in yourself? Mind sharing what the total damage cost wise was and what gear brand you went with?

I bought Yukon 4:88s from Northridge4X4 with the forum discount. @@$700 for a complete set with master rebuild kit, with the full intention of a self install. I bought about $300 worth of specialty tools for the the job and studied every video on gear swapping. I planned to tackle it right after retirement in 2019. We had some family issues and we moved to another State. Everything was pushed back. There was no rush, because the auto was fine pushing me forward with 7 out of 8 gears. After a couple of years into retirement, with the mentality of "is my time worth the money saved?", I decided to ask around for the cost of a regear. I got a quote for $800 and had them do it. I have some regret, since they wouldn't warranty the install because I brought them the parts, but I could fix anything if it werent botched too bad. I've changed out a few seals in the last few months, but was okay with that. The wear pattern is spot on when I changed out the gear oil and I'm back to about 16mpgs with my heavy foot.

 

[At Risk Ute]

I am running 37" BFG KM3's without a regear and honestly on the road I don't notice a huge difference. I do have a TazerJL and changed the tire size appropriately (actually measure your tires ground to top). I am sure a regear would make a difference but using it as a pavement princess I do not think its a requirement by any means. Now if you plan to wheel it, especially if you will be rock crawling in any sense, then it may be a different story.

I‘m going to do the same. Run 37” KM3s with the 2.0T / 8AT on stock 4.10 gears. Looking forward to lower RPM on the interstate. I‘ll decide whether or not to regear after wheeling full time this summer.

My friends have a tour company in Colorado. Their guide Jeeps are JKURs running 37s / 5.13s while their client Jeeps are JLURs running 35s / stock 4.10s. Know I’m comparing myriad apples and oranges, but the JKURs want to run away from the JLURs in 4L.

 

[Tharris]

I'm sure I'll get the "use the search" response, but I did and didn't find a definitive answer. If I put 37x12.5x17's on my 2021 Rubicon, do I need to regear or not? I'm thinking "no" that 4.11's are fine and 4.88's are better, but I just want to know is regearing an immediate need if going from 35's to 37s?

I can tell you from my experience that regearing for 35s is not necessary. I JUST regeared my Jeep to 5.13s. I’m fully built, full armor bumpers etc. I had 35s for a year with light mods and couldn’t tell a difference from stock. I moved to 37s, fully loaded and lost 8th gear. Big difference, however if you’re rolling light mods with 37s you won’t need to regear unless you feel you want to.

 

[J0E]

My neighbor has a two JTRs. One with a 3.6 on 37's, the other diesel on 38's. He says after driving the diesel, the 3.6 feels like it needs 4.88 to use 8th gear, but the diesel is fine.

For sure you won't need a regear for crawling.

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