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Re-gear opinions 2020 JL Wrangler Pentastar 6spd manual

Rockywoolf

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I believe that’s the JK chart. If you’re wanting to wheel, my suggestion is to find some take out rubicon axles and run the 4.10s. If you want to move up to 35s or more you’ll be back in the same boat as it being short on power on the highway though. 4.88s are a good pairing to 35s. We have 5.13s with 37s on my 6 speed and I think it’s a great match

Brett
I too put 5.13s on my manual and put 37s on. Made a world of difference. I could not be happier.
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Rockywoolf

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I bought a JT, put 37s on it with 5:13 gears, here is a snapshot of the dash
Jeep Wrangler JL Re-gear opinions 2020 JL Wrangler Pentastar 6spd manual 1610124352179
 

word302

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It is horrible, especially with my boat/trailer, which is light. Even unladen it is bad. I have no clue why they went so tall with it, as it has zero to do with CAFE.
Isn’t reverse even higher in the JK? I can’t imagine trying to back anything up with a higher reverse.
 

word302

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I agree it's atrocious jeep set up non Rubicon models with 3.45 gears. Regearing is a necessity there.

But 4.10 gears are perfectly adequate for the average guy running 37s with a manual. I considered seriously regearing for a while, 4 hi and hill climbs wasn't pleasant. But I realized I could shift to 4 low and start in 4th and run up to 6th rather than pay 2k to stubbornly use 1st in 4 hi.

In the end, final drive is what matters, the ratio of rpm to ground speed. It doesn't matter if you regear the axles or choose a different transmission and transfer case combination, it's all about the math and final drive.

If you have $2000 burning a whole in your pocket, by all means regear your axles. But if you have a harder time supporting your wheeling addiction, take full advantage of the gear spread available to you, and spend that money on something more useful
You must live in a flat world. Even with small inclines I was dropping to 3rd gear on the Highway to get any kind of acceleration with 37s and the stock 4.10 gearing.
 

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word302

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yeah, im
Pretty happy with 4.56 and 315/70r17
can use 6th easy at 60/65mph

also part reason is at 4.56, i believe the pinion ring gear is larger. Once you go to 4.88/5.13 etc they become smaller(weaker)

will need more gearing if i go 37s.
Have you seen the new 5.13 pinions? They are massive. You’ll break all kinds of other parts before you even think about breaking a pinion, even with 5.38s.
 

Rockywoolf

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Jeep Wrangler JL Re-gear opinions 2020 JL Wrangler Pentastar 6spd manual 1610135619358

From my 2018 JLUR on 37s with 5.13 gears. Manual trans
 

OBJLU

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I moved to 39's, the 5.13's still pull pretty nice. Looking at swapping in a semi-float 60 if the price is right, if that happens I MIGHT go with 5.38's but then the concern is the ring and pinion because I'm keeping my 44 front.
 
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My two cents, have the 3.6L Sport S manual mated to a 4.88 and 35s. Perfect match. 4.56 would be too tall yet, and while 5.13 would be nice you'd be revving your engine on 80 mph highways. I'd recommend 5.13 on 37s.

Regearing and tires was the best money spent, by far.
 
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greenMarine

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First off: Thank You All for the data points and contributions to this thread. Quite valuable!

I have a 2022 JL Sport (2-Door) with the 220 rear/183 front axle and the manual transmission… and 3.45 gears. I knew immediately gears would be getting swapped – the 3.45’s effectively makes this a 4-speed rig. I’ll tow a trailer when overlanding and traveling – about 1,500#’s on the trailer – tires are 285/70/17’s on 17x9 which also measure exactly 32” tall (same as the stock) 245/75/17’s on the stock width… I wouldn’t think about towing with the 3.45’s on a stock tire.

I was thinking 4.88’s or 5.13’s before I DROVE the JL with a manual – now I am considering 4.56 … because I am getting 19mpg hand calculated and that’s keeping it in 4th most of the time.

The trailer I tow – has me considering 4.88’s to have enough torque to pull

So anyone weighing in with a 33” or 34” tire and a gear ratio deeper than 4.56 would be appreciated on gas mpg and trailer towing - also highway speeds greater than 75 might be a valuable bit of information.

I noted that ‘rustyshakelford’ said he’s on 37’s, 5.13’s, 2500rpm at 70mph and getting 16.5 mpg that’s respectable…

I’ll drive 20,000 miles a year (minimum) in the subject vehicle traveling around the lower 48 to camping and off-roading destinations. MPG matters. With a 17-gallon fuel tank it matters.







More information:

The Jeep came with some light 245/75/17 tires that measure 32” and I replaced them with 285/70/17 on 17x9 which also measure exactly 32” tall. With the SPORT Gear ratio – 3.35 something 6th gear has been rather useless on even the stock tires. I live in the Dallas Fort Worth area of Texas about 660’ above sea level and relatively flat. 6th gear is useless unless you can hold 80 with no hills. The rolling highways of Texas do not allow for this. I stay mostly in 4th Gear – and habitually go back into 5th and occasionally 6th gear. Fuel economy is best in 4th – not 5th – not 6th the engine is often below 2,000 rpm in the gears, and I find my best fuel econ is at 2,500 rpms. Difficult to hold 2,500 rpms stock. As previously stated, on another thread 4.10 should be the stock gear ratio with the manual -

Fundamentally this is a 4-speed transmission. I have about 1800 miles on the Jeep and have had it about a month now. I will be towing a 1,500# trailer – will probably eventually go to 35’s or 285/75/17 sooner than later. Love the Jeep – I’ve built a ton of Jeeps, TJ’s, JK’s, and a bunch of other Jeeps… This is a strange situation. In all my JK *also 2-doors I ran 5.13’s and 35’s and 37’s and never thought twice about it.
 

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Since posting last year, I get about 17.5mpg average per tank w/ 4.88 and 315/70r17's (34.4" diameter). 18.5mpg cruising at 65 on flat highways, then mpg goes down above 65, but still getting 17mpg or so at 80 I believe. City is around 16-17mpg or something. I started paying for 87 octane, which is mid-grade up here, and saw my mpg go up about 1 on average to what is here. Only a few less mpg than what I was getting stock on regular gas.

Haven't look at my mpg towing, since I don't do much of it, but it would take a big hit. I'm definitely glad I have the 4.88 when I have anything hitched on though.
 

scott.roams

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I have nothing to add, but this was a really interesting discussion to read through. Even though it's an older thread, it still seems pertinent.

I've not done by build order yet, but judging from this thread - I'm going to err on the side of my 3.6L Pentastar with 6-speed manual and 4.88 gears with 35's. We have a teardrop trailer we use for weekend camping. I'd be more concerned the 4.88's are on the cusp of being not so great (for lack of better terminology?) for daily driving? Regardless, great reading as this is very new to me.
 
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Probably last post here, but relevant. Just swapped my oil with full-synthetic Valvoline, and my mileage went up by another 1 mpg. This is about the second oil change I've done since doing my own maintenance, so finally got all the crap out from the dealership. (Their "synthetic" is no way synthetic). Now getting 18.5-19 mpg average, 19.5+ on highway. Moral of the story, highly recommend doing your own maintenance and actually knowing what fluids go in your jeep. Mid-grade and good oil have made over a 10% difference to my gas mileage, with the same heavy foot and soft tires (30-32 road pressure)
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