"Do I REALLY need to re-gear for 37s?" - Yes. Yes you do.

[Zachanadandy]

I have to wonder if the guys saying not to regear have ever driven one that was regeared. Or if they've ever felt the benefits of a regear in any vehicle for that matter.
My other thought for those that argue 5th on 38s is the same as 8th on 33s...Just tossing out gear vs tires for the argument, not sure if those would make the right ratios vs RPMs...WHY waste gears, you have an 8spd, why wouldn't you want to use all 8 gears???

Sure, around town or maybe even on the HWY it seems fine, but your wasting one of the best parts of the JL/JT if your not using all 8 gears.
That's not to mention offroad. My old CJ5 with a healthy AMC360 had plenty of get up and go on the pavement with 33s and 3.53s. I sure wish it had lower gears every time I got it offroad, especially in the sand. And no, low range isn't always the answer for offroading.

Just my thoughts and opinions. But maybe it's something to think about...

The 4.7-1 1st gear is the entire reason we can get away with taller gears. A tj or early jk auto had a 2.86 1st gear. You'd need 6.72 axle gears just to match a JL or JT with 4.10s on the low end. The idea that you're wasting gears is ridiculous. I see 8th regularly with 37s. No it won't hold a hill or a high headwind, but it's not supposed to and didn't stock. The stock JLU non-rubicon has 3.45s and 32" tires. That's the equivalent of 4.10s and 37s. They get down the road just fine. See 8th gear under low loads, as designed. Before we here "but the JLU is lighter", it's 400lbs lighter. Our JLUR weighs more than my JTM on 37s thanks to it's full skids, upgraded sliders, and 39s. The weight difference is negligible comparing ~5k lb vehicles. I'm not saying 4.10s are optimal for 37s, but it's far better than 5.38s and 38s was. "Proper gearing" is more opinion than fact with this transmission.

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[Dickster]

I do have a question though, why is it we always hear about people say they need to regear to get power back from going to a larger tire, but rarely hear talk about how to improve their braking from all the increased weight?

Who needs brakes? We're all about going 95mph is a jeep not stopping.

 

[Gladiatorx2]

I gotta join this discussion about gears, especially with the 8 spd in our vehicle and other Chrysler products. On my Gladiator w/37's and 4.10 gears it was very liveable but far from optimal as far as acceleration and driveability. MPG was not bad at all if driven super easy at speeds below 70. I easily got over 20 MPG but the previous owner managed only 12.9! He traded it in on a new Mustang GT so I am guessing that he was a performance oriented driver. It would shift in to 8th fairly easily but would downshift under even light loads.

When I first bought the 2023 Spot S with the Max Tow and the 245/75r17's it literally felt like a performance car in comparison. While taking off on flat ground in was in 5th gear by 40 MPH where the Rubicon would have been in 3rd or 4th. It is strange and you won't believe me but the Rubicon while driving to trade it in got better MPG than I could muster from the Max Tow with the much smaller tires. I tried hard but I couldn't duplicate the MPG no matter how hard that I tried and yes, it held 8th longer but still down shifted under load ( the way that it was designed).

On the Max Tow now with 315's with the same 4.10 gears it retains nearly identical performance/driveability as with the 245's ( after correcting to 34.
4 ). These tires are listed as weighing either 52 or 54 lbs and are on Mojave wheels. Strictly city stop and go economy went down but surprisedly highway economy went up.

For what it's worth it depends on your wants/needs. In my case now the 4.10's are perfect for me. In the case of the Rubicon if cost was not a factor a gear change to the right gear would be beneficial in many ways. But I would not do 5.13.

Now for the fun part. A Pursuit Charger or a civilian Chrysler 300 downshifts on the same incline as much as any of my Gladiator 's. It is what it is designed to do for optimal performance.

 

[Dickster]

Gears are a touchy subject. I think what your doing with your jeep will decide that for you. We have people running faster speeds with the mojave, people crawling with rubicons, and people mall crawling. The cost of getting Gears done is not a small bill for something not easily changed back. Definitely have to ask yourself what you really plan on doing with your jeep. I went with 5.38s with 38in tires, some days I wished I went with 5.13s but I rarely drive my rig over 65mph. My next set of tires will be 40s. I was looking for more crawling performance and for what I do with my rig I am more that happy with my choice.

Everyone here has good points with data behind it but at the end of the day it's your money and your ride.

 

[YYCSahara]

Personally, I tried to select the lowest weight wheel/tire combo when going from 33 to "37s". The difference between the stock and 37 package is about 4 lbs more per corner if I were to trust my bathroom scale haha.
I have 0 issues getting the truck into 8th gear daily. Gas mileage is about the same too. Maybe because mine aren't true 37s and only on paper, but don't see a need for a regear at this time.

 

[JKenTex]

This is what I've been considering too. For one that's primarily street, and not at high alt. etc. it seems like a better plan.

I'm really surprised how my '24 Mojave handles and drives now, it's got a little to give up and still drive great. I've called it a go-cart, because as long as I can hold on, it'll take a corner on the street at just about any speed, and for the reduction in power from what I'm used to, the 8-spd does help with pretty impressed acceleration. But, that's not what I bought it for.

There are K02's in 37's that are really light. I'm curious what combination you've got? Method 703's have caught my eye for being not flashy but light.

 

[jpfeif34]

Some of y'all must have been riving rocket ships before your Gladiator. I had went from a 2016 Yukon Denali with the 6.2L to a stock Rubicon and I felt like the 3.6 had a noticeable increase in pep. I've had several other Jeeps but compared to my TJ from college, this thing feels incredible.

I have the Patagonia X/T 37s on AEV Saltas and I barely noticed a difference from stock. I have no intention to re-gear and on the highway I'm still getting 19-20 MPG with cruise set at 65 (in a 60).

Yo, brother, Where are you located? How are the patagonia Xt's in the 37"? Had it in snow/ mud/ offroad? Lert me know. Very interested in your take on these tires. Can't find many reviews (besides the bad ones)

 

[jpfeif34]

Personally, I tried to select the lowest weight wheel/tire combo when going from 33 to "37s". The difference between the stock and 37 package is about 4 lbs more per corner if I were to trust my bathroom scale haha.
I have 0 issues getting the truck into 8th gear daily. Gas mileage is about the same too. Maybe because mine aren't true 37s and only on paper, but don't see a need for a regear at this time.

What wheel and tire set up did you go with? could you post some photos?

 

[Sikjeep2]

"Do I REALLY need to re-gear for 37s?" -

No, No you don't.

End thread


You can ask this question in many forums or shops you will get different answers every time.

 

[mtoddsolomon]

Yo, brother, Where are you located? How are the patagonia Xt's in the 37"? Had it in snow/ mud/ offroad? Lert me know. Very interested in your take on these tires. Can't find many reviews (besides the bad ones)

I live in coastal South Carolina so mostly sand and mud around here and they have been great. I do go up to the mountains about every other month to mountain bike where I camp off the beaten path and they were much better in the rocky clay. They're also super quite and I'll buy them again.

 

[mtoddsolomon]

Am I reading that right, you felt like the 6.2 Denali had less go than the 3.6 JT?

We've got a 6.2 Silverado in the family and that thing was faster than my 5.7 Tundra, both of which would hit 60 easily a couple seconds before my JT, like in the 5-6s range. I've seen 6.2s run quarters in the 14s. Pretty much every JT Ive seen, including the diesel is closer to 8s to 60.

Maybe mine was different but it made a lot of noise without a lot of movement. I have a 996 911 as a fun car so its all relative. I'm not a drag racing guy, but i wouldn't choose a yukon or a gladiator to pull out into traffic if a tractor trailer was coming. But I'd take the gladiator of the two.,

 

[JTGuy]

My 4.88s are the best thing I ever did that wasn't really needed. .

 

[Pilsner]

My JTM with the auto, 4.10s and 35" tires feels better than my Tacomas did with 33s, that's including the MT with 4.30s. Its really still a subjective decision.

I felt more of a change switching to 35s on my 5.7 Tundra than I did on the Jeep. Having said that, no amount of gearing advantage would give me the pep the Tundra had despite the noticeable change. I think the 850RE does a great job, I still routinely see 8th and can get 20mpg on highway trips, city is pretty much locked at 17 hand calculated. My Tacomas never peaked above 17, even stock.

If I go 37s I certainly wait to see about regearing, because as it is, its hard to imagine another 4% or 5% larger tire would make it as sluggish as those Tacomas. If its even slightly better than they were I'm good.

As long as the choice you make, makes you happy then that's a win.

That's for sure. 37s are a big jump though, both in size and weight. I am on 4.88s and it drives fine, but I could have gone a touch deeper probably. I would honestly go 5.13s if I did it again. I'm also looking at going bigger than 37s after the axles are beefed up.

 

[jpfeif34]

I live in coastal South Carolina so mostly sand and mud around here and they have been great. I do go up to the mountains about every other month to mountain bike where I camp off the beaten path and they were much better in the rocky clay. They're also super quite and I'll buy them again.

Good in the mud?? How many miles do you have on them? And how many do you think you’ll get out of em?

 

[CJ5w4wdSmokyOnMyTail]

What wheel and tire set up did you go with? could you post some photos?

Betcha he is talking about KO2 tires. They are the lightest weight 37s and are well known for running on the smaller side.

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