Gear change?

AtlJeeper1629

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Random question, only because I have never changed the gears in any of my keeps. I and currently running 37s on my rubicon. If I maintain 37s or go bigger, would I better going to 5.13 gears? My gears now are currently stock. Thanks in advance for any advice!!

 

SouthernJL

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Random question, only because I have never changed the gears in any of my keeps. I and currently running 37s on my rubicon. If I maintain 37s or go bigger, would I better going to 5.13 gears? My gears now are currently stock. Thanks in advance for any advice!!
You'll get varying answers to your question from the 4.10s are fine up to 5.38s, depending on how big you eventually want to go. It also depends on if you have the 2.0 or the 3.6.

Judging from your user handle, you're in Atlanta, so am I. One of the variables to consider is loss of HP due to altitude. Not as big a deal if you're in the 2.0 but the 3.6 does lose some horses as you climb altitude. Here in Atlanta close to sea level, we're not really affected so you're good in that respect. Many of the Jeepers that recommend gear changes with 37s are at higher altitudes and their loss of HP makes a gear change necessary.

Other factors to consider are
1. Weight of your wheel tire combo
2. How heavy is your Jeep (steel bumpers, accessories, weight of gear you typically carry etc)
3. How you plan to use your Jeep
4. Was the loss of pep noticeable to you such that you want to regain it

I chose a light wheel/tire combo (37 inch C load Ko2s), my Jeep is light and my use case is all street for the moment so I stayed with the 4.10s and I'm perfectly content. When I had a JK and went up to 35s, I had to get the gears changed, it sucked with that old 5 speed trans. But in this JL, it's not bad at all to me with the 8 speed trans.

Just my 2 cents
 

sourdough

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I ran my JLR auto. with 37's and it was fine off road. Highway no way. My new 35's are much better and I can live with stock 4.10's.
 

Steph1

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I've never regeared either on my previous Jeeps until a few months ago where I regeared Jeep to 4.56 to turn my 315/70s and will say that I totally regret not regearing my previous Jeeps. It would have made them so much more enjoyable to drive on top of looking good.

I was just too worried and found regearing too much intrusive to go ahead and bite the bullet. Now that I know what it does and how simple it is, I can say without a doubt that it is the absolute best mod I've ever done to any of my Jeeps. It's one of those things that you have to experience to realize how much difference it makes.

It is incredible to feel your jeep turn 35s as if, if not easier than it turned the stock tires. It brings an indescribable satisfaction that I'm experiencing for the first time and that I will certainly not hesitate to repeat and make important part of futur Jeep builds, no matter how much torque I have, it is the only way to bring back power to stock levels.
 

J1337P

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What engine? Running 38s on diesel and no need for a regear.
 


Some Random Guy

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Do whatever you want, including nothing!
I did it on my 3.6 M/T when I jumped to 39’s. I went to 5.13 and enjoyed it. However, I also ran around in the stock 4.10’s for a while and it was fine. Just became a 4 speed.
You’ll gain acceleration and might get back some minor MPG because the transmission will have more available gears to choose from. You’ll also slow down your crawl speed in 4L.
Good gear installers are hard to come by. I’d recommend contacting @chevymitchell because he’s near you for either recommendations or to just schedule with him.
 

CarbonSteel

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There will be plenty of people with different opinions including some who will say that 37's and stock gears are "just fine". Depending on the engine, it may be "OK", but it will never be the same as re-gearing to the proper ratio.

My 2019 has the non-etorque 3.6L and 8 speed. As a Rubicon it came with 33" tires and 4.10 gears which were OK at sea level. In the mountains/hills/head winds, it struggled some, but was ok for the most part.

I upgraded to 35" tires and it was a PITA on anything other than flat ground at sea level. Constantly up and down shifting, never remaining in 8th gear on the highway, etc.

I re-geared to 4.88 and with 35's, it was really peppy and ran great. I upgraded to 37's and though I lost some of the torque, it was still good at sea level.

I moved to Colorado and at 7K, it lost enough torque to be very noticeable and it did struggle in the mountains and head winds. I recently re-geared to 5.13--which is what I should have done in the first place, but I had not planned to go to 37's and did not know I was moving to CO permanently when I geared the first time.

With 5.13's, it runs great (again), so despite what some may say, when you increase your tire size, you are throwing the torque curve off on the engine and it will have an effect. Some engines handle it better than others.

If you decide to re-gear, then reach out to @chevymitchell (who just did my 5.13s)--he will do you right!

I would do this with 37's:

2.0T = 4.88
3.6L = 5.13
 
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AtlJeeper1629

AtlJeeper1629

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There will be plenty of people with different opinions including some who will say that 37's and stock gears are "just fine". Depending on the engine, it may be "OK", but it will never be the same as re-gearing to the proper ratio.

My 2019 has the non-etorque 3.6L and 8 speed. As a Rubicon it came with 33" tires and 4.10 gears which were OK at sea level. In the mountains/hills/head winds, it struggled some, but was ok for the most part.

I upgraded to 35" tires and it was a PITA on anything other than flat ground at sea level. Constantly up and down shifting, never remaining in 8th gear on the highway, etc.

I re-geared to 4.88 and with 35's, it was really peppy and ran great. I upgraded to 37's and though I lost some of the torque, it was still good at sea level.

I moved to Colorado and at 7K, it lost enough torque to be very noticeable and it did struggle in the mountains and head winds. I recently re-geared to 5.13--which is what I should have done in the first place, but I had not planned to go to 37's and did not know I was moving to CO permanently when I geared the first time.

With 5.13's, it runs great (again), so despite what some may say, when you increase your tire size, you are throwing the torque curve off on the engine and it will have an effect. Some engines handle it better than others.

If you decide to re-gear, then reach out to @chevymitchell (who just did my 5.13s)--he will do you right!

I would do this with 37's:

2.0T = 4.88
3.6L = 5.13
I have a 3.6L. Looking like I may go ahead and go with the 5.13. Is @chevymitchell local to Atlanta?
 



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