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Should I Regear?

Ian4351

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I have JLU Sport 2L turbo. I just put on 35" tires with a 2 1/2 inch lift. I've noticed power/mileage issues. Which was expected with the added mods. I'm just wondering how important it is to regear from the stock 3.45. And if I do regear, which ratio would be best?
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Personal opinion and maybe somewhat unpopular but you should re-gear to compensate for the tires you're planning on running for the long term. Doesn't matter if it's a Rubicon and its 4.10s going to 35s or a Sport and its 3.45s going to the same. It's the single biggest quality of life improvement you can make for mileage and driveability. It will make every time you take your Jeep out more enjoyable. You may have to wait a bit longer for those bumpers, winches and lights you'll never use but...

I went with 4.56s on my 2dr Rubicon and 35s.
 

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Yes you should regear.

Minimum of 4.56 gears for 35" tires. 4.10 would work if you already had those in a Rubicon but it's no more expensive to go to 4.56.

4.88 is also good for 35s.

I wouldn't go bigger than 35s on Sport axles, especially if you have the M200 in the rear.

If you plan on going with bigger tires in the long run, don't spend money on Sport axles. Live with the stock gears and save up for an axle upgrade. Either Rubicon axles or aftermarket.
 

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I'd regear, 3.45s are a bit tall for bigger tires IMO. I like 4.10 or 4.56 for 35s, especially with the 8 speed auto in the JL. I think 4.88s are a bit short for day-to-day driving with 35s. Of course, this is personal preference, but I ran 4.88s with small 37s in my JK with the 5 speed auto. Even with the taller ratios in the JK auto, 4.88 was about as short as I found enjoyable with 37s.

Which ratio you pick really is personal preference coupled with need, which kind of makes recommendations hard - different folks react to shorter or taller gearing feel differently due to different driving styles and such. However, the 4.10-4.88 range is pretty much a sweet spot, and 4.56 falls right in the middle.
 
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Ian4351

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I'd regear, 3.45s are a bit tall for bigger tires IMO. I like 4.10 or 4.56 for 35s, especially with the 8 speed auto in the JL. I think 4.88s are a bit short for day-to-day driving with 35s. Of course, this is personal preference, but I ran 4.88s with small 37s in my JK with the 5 speed auto. Even with the taller ratios in the JK auto, 4.88 was about as short as I found enjoyable with 37s.

Which ratio you pick really is personal preference coupled with need, which kind of makes recommendations hard - different folks react to shorter or taller gearing feel differently due to different driving styles and such. However, the 4.10-4.88 range is pretty much a sweet spot, and 4.56 falls right in the middle.


I'll be using the jeep mostly for daily driving as of now. if anything later on, easier trails no rock crawling. I'm seeing a lot of information saying that 4.56 is the way to go. I have the 8 speed automatic and it doesn't go into 8th gear anymore on the highway. Can you tell me what differences I'll notice with the 4.56 as compared to the 3.45 I have now?
Admittedly I'm new to all these jeep mods with regard to gears and axles. Any information helps.
 

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I have a JLUR 6-speed that I'm adding 35s, bumpers etc. Have ordered 4.88s to be installed. Stock 33s and 410s with 6-speed slightly to tall in my experience in 2hi and 4hi
 

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I'll be using the jeep mostly for daily driving as of now. if anything later on, easier trails no rock crawling. I'm seeing a lot of information saying that 4.56 is the way to go. I have the 8 speed automatic and it doesn't go into 8th gear anymore on the highway. Can you tell me what differences I'll notice with the 4.56 as compared to the 3.45 I have now?
Admittedly I'm new to all these jeep mods with regard to gears and axles. Any information helps.
Basically what you'll notice is that the Jeep will be turning different RPMs in different gears, and it'll feel torquier:

Jeep Wrangler JL Should I Regear? 1658935194740


You'll be gaining ~500 engine RPM at highway speed to turn those 35s, which means there's more torque in use keeping things rolling. The Jeep will have an easier time maintaining speed up hills and will feel like it's getting more use of available torque. In 4L on the trail you'll notice that the Jeep is revving higher before forward movement occurs and that it generally wants to crawl more slowly.
 
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Ian4351

Ian4351

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Basically what you'll notice is that the Jeep will be turning different RPMs in different gears, and it'll feel torquier:

Jeep Wrangler JL Should I Regear? 1658935194740


You'll be gaining ~500 engine RPM at highway speed to turn those 35s, which means there's more torque in use keeping things rolling. The Jeep will have an easier time maintaining speed up hills and will feel like it's getting more use of available torque. In 4L on the trail you'll notice that the Jeep is revving higher before forward movement occurs and that it generally wants to crawl more slowly.

Thank you for the chart. I've been looking at all kinds of them but this looks very readable and specific to my engine. Much appreciated. So basically with a 4.10 or 4.56 it should feel like its returning back to stock driving feel? (obviously not completely back to stock) but more or less? Also I should regain some MPG?
 

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I'll be using the jeep mostly for daily driving as of now. if anything later on, easier trails no rock crawling. I'm seeing a lot of information saying that 4.56 is the way to go. I have the 8 speed automatic and it doesn't go into 8th gear anymore on the highway. Can you tell me what differences I'll notice with the 4.56 as compared to the 3.45 I have now?
Admittedly I'm new to all these jeep mods with regard to gears and axles. Any information helps.
Have you done rock crawling? Everyone I know who said they weren’t planning to changed their mind 30 seconds into their first time.
Also, start by identifying installers and seeing if anyone here has experience with them. If there are no good ones with recent JL/JT/Bronco experiences you have hard choices to make between traveling, doing it yourself, or gambling.
 

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Ian4351

Ian4351

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Have you done rock crawling? Everyone I know who said they weren’t planning to changed their mind 30 seconds into their first time.
Also, start by identifying installers and seeing if anyone here has experience with them. If there are no good ones with recent JL/JT/Bronco experiences you have hard choices to make between traveling, doing it yourself, or gambling.
I've not done rock crawling but I have an idea I'd probably love it lol. I do have a good shop, very reputable. Did my research with them and they work with jeeps all the time. I had them put my tires and wheels on and an AEV dual sport 2 1/2 inch lift on it. Very happy with what they did. I'd recommend them to any on Long Island, NY
 

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I've not done rock crawling but I have an idea I'd probably love it lol. I do have a good shop, very reputable. Did my research with them and they work with jeeps all the time. I had them put my tires and wheels on and an AEV dual sport 2 1/2 inch lift on it. Very happy with what they did. I'd recommend them to any on Long Island, NY
Great news! Mind posting up a name for others in your area?
 

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Thank you for the chart. I've been looking at all kinds of them but this looks very readable and specific to my engine. Much appreciated. So basically with a 4.10 or 4.56 it should feel like its returning back to stock driving feel? (obviously not completely back to stock) but more or less? Also I should regain some MPG?
Yep, it'll feel closer to stock in terms of responsiveness, and you may get an MPG or two back, but gears are really just a part of that whole calculation and I wouldn't expect anything drastic.
 

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I'll be using the jeep mostly for daily driving as of now. if anything later on, easier trails no rock crawling. I'm seeing a lot of information saying that 4.56 is the way to go. I have the 8 speed automatic and it doesn't go into 8th gear anymore on the highway. Can you tell me what differences I'll notice with the 4.56 as compared to the 3.45 I have now?
Admittedly I'm new to all these jeep mods with regard to gears and axles. Any information helps.
You'll see 8th gear again and hold it much better. Improvements to fuel economy and acceleration. Basically you're putting your engine back into the powerband it should be in. Since you're in a Sport, it'll more than likely feel better than stock. There was a noticable fall off when I went from 33s to 35s in my Rubicon with the 4.10 gears. It'll be night and day for you.
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