Running 37" tires + with stock gearing? experiences???

Cherry Bomb

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2019 JLUR with 4.10s on 37" Nitto Grapplers. I have the 2.0T and live in Colorado. No problems hitting all 8 gears, can go over 100mph + in the mountains, no problems on trails and I get 22mph highway, 19 in the city. Everyone says go 4.88 but I haven't had a need. I was hoping the 37s would actually slow me down because the 2.0 is fast and gets me in trouble. The 37s didn't slow me down at all. The only JLURs I hear switching from the 4.10s are the 3.6s. Glad I got the 2.0 Hurricane engine.
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sourdough

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I refuse to waste money regearing my JLR 3.6, auto. on 37's. D44 upgrades are like investing good money after bad:puke:. I would/will on a set of D44 392 axles :clap: when folks start swapping for D60's:giggle:
 

Cherry Bomb

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I refuse to waste money regearing my JLR 3.6, auto. on 37's. D44 upgrades are like investing good money after bad:puke:. I would/will on a set of D44 392 axles :clap: when folks start swapping for D60's:giggle:
Same. Maybe in 5 years when I'm bored I will put my 44s on my YJ and switch to D60s but ya, I'd rather put my money elsewhere. The problem is all the bad advice from people driving JKs that think the JL are just like JKs. My turbo kicks in at 2500 rpm like it did on 33s. 37s just lowered my mpg slightly. I'm never in the slow lane unless I have JKs following me to the trail.
 

limeade

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I'm never in the slow lane unless I have JKs following me to the trail.
Got a good laugh out of that!! :LOL:

I also have a 2.0T with 37" Trail Grapplers and have not felt the need to changing gearing. One day I will (mostly for better crawl ratio), but the 2.0T still feels like a rocket ship.
 

Cherry Bomb

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Got a good laugh out of that!! :LOL:

I also have a 2.0T with 37" Trail Grapplers and have not felt the need to changing gearing. One day I will (mostly for better crawl ratio), but the 2.0T still feels like a rocket ship.
Lol mine is a Mojito also, I think the color makes them even faster lol
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Headbarcode

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38x13.5 milestar pat's that measure just under 37.5", 3.5" Gamechanger that gave 4.25" over stock, and 4.10 factory gears on my 2.0/8-speed Rubi. Regearing isn't even a blip on my radar. Tazer has me seeing 8th all the time, and it pulls very well from idle to speeds I shouldn't be doing in a wrangler.
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Cherry Bomb

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38x13.5 milestar pat's that measure just under 37.5", 3.5" Gamechanger that gave 4.25" over stock, and 4.10 factory gears on my 2.0/8-speed Rubi. Regearing isn't even a blip on my radar. Tazer has me seeing 8th all the time, and it pulls very well from idle to speeds I shouldn't be doing in a wrangler.
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Nice rig! I can't help but wonder if it has to do with the 2.0, I use Tazer as well. I'm thinking maybe it's the JLURs with the 3.6 that have a problem with gearing since we with the 2.0s get more torque and hp. I see that decal "I'm built like a brick, not meant to go fast" and I think, "BS, not me". Fast and can go anywhere is more like it. I'm not even interested in the Hemi, the 2.0 is fast enough for me. I went with the EVO stage 4 Overland 4.5" with 2.5 Kings.
 

JLAFAKASI

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37s will work on an auto JL Rubicon which has 4.10 gears. I wouldn't reccomend it with the Sahara or Sport which have 3.45 gears.

We don't have the JK with diesel in the States. A diesel with 3.73 may work.
Would say 37s on a rubicon with stock gearing is like 35s on sport gearing.
 

Caymanedge

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Well my '21
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on 38 Pats was ok with the 2.0 and 8spd transmission. However, I just went to 4:88 and it much smoother, Shifts quicker and never lugs along. Very happy with it.
 

FLUndertaker

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I am running 37’s and 4.88’s on my 2 door, and I have 8th gear back. Turns about 2200 RPM at 70mph. Stock tires and gears was about 2000 RPM at 70mph. All that said, I am kicking around doing 5.13’s on the Gladiator. Wife is running 37 Trail Grapplers and they are heavy, plus the truck is heavier as well.
5:13 with 37 ridge grapplers on my JT. Absolutely no regrets. Actually thankful I ignored the nonsense about the smaller pinion head on the 513 vs the 4.88. Between the regearing and the pedal commander my glady is fun as hell to drive and will surprise folks by its acceleration from a stop. Highway cruising is 2500 rpms at 77 mph in 8th gear. Plenty of passing power when it kicks down to 6th.
 

Upsidwn

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I mean… there’s a reason all the factory offerings that have 35” tires come with 4.56’s. I don’t care for the 4.10’s with 35’s personally, and think the 4.56’s are a good ratio for 35’s on all the past rigs I have. When I make the step to 37’s it’ll be at least 4.88’s
 

Zandcwhite

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Does anyone here have experience running stock gearing while running 37+ inch tires??

Can you tell me what jeep you had even if it was a previous JK. Did it damage anything? What kind of terrain did you drive on? Length of time/miles? Anything and everything you could tell me about the experience is greatly appreciated!!
We've been on 37's for ~14 months. With the 4.7-1 1st gear and the 2.0t it still pulls way harder from a stop than our 09 jk did stock. We still see 8th gear on the highway all the time, but I tend to set the cruise control at 85mph on long road trips. We've been on multiple 1-3k mile road trips including up to Tillamook, moab twice, ouray, and AZ last week. 25k miles with the tires and lift and 41k total. Ball joints are wore out and will be replaced next week when they come in. We've upgraded most of the steering components along the way, not because they were damaged but more for the extra piece of mind. The only damage we did was the steering stabilizer, but that was smashed on a rock, not tire related. Would it drive closer to stock with 4.88's? Of course. Is it still better geared than a stock jk? Yep. Gearing down would improve acceleration a bit, but the idea that holding 8th gear at higher rpms is somehow beneficial is lost on me.
 

OllieChristopher

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Well said Zach.

33" tires with 4.10 gearing. When going to a 37" tire you will need 4.60 gear set to get the same ratio as stock.

As a disclaimer I do not own a Jeep. But I will tell you anytime you go to a large tire like the 37" you have to make a whole bunch of drivetrain/steering modifications to make it reliable for any kind of hard wheeling.
 
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