Best Gear Ratio For Larger Tires (Jeep Gladiator & Wrangler JL) | Inside Line

Adding larger tires to your Jeep impacts its performance. To compensate for taller tires, you must change your Jeep's differential gearing. Just as important as picking the right tire for your needs will be getting the correct gear ratio. In this video, I'll go over the different gear ratios offered for the Jeep Gladiator and JL Wrangler platform. I'll also weigh in with my real-world experience on the subject.
00:00 : Introduction
00:31 35's with stock gearing
01:12 Best gear ratio for 37's
01:56 How tire weight impacts gearing
03:24 5.13 vs 4.88
04:56 Gearing for 38's
07:59 Pinion size
10:39 5.38 gears and 40's
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[@martinklaus2203]

Definitely 5.13's. I re-geared the same time I got my lift and 37's. No regrets.

[@jimstoneman1732]

My rule of thumb is to calculate the percentage of tire size change (ie. 32" to 35" is about 10%), add 10% to the gear ratio (4.10 to 4.56), then go up one more to compensate for the extra weight of the heavier tires (4.88). Always worked for me!

[@trailsandtailpipes]

‘21 JT, went with 5.13s and 37s, been running that set up for over a year, absolutely love it!! Running Milestar Patagonia ATs, really love them. This does have me thinking if I could run 38s though for my next set of tires…

[@machine2747]

You're videos are always very informative. I went with the Dynatrac XD60/ProRock 44 combination with 5:13s on Nitto 37s. It works great although any head wind kills mileage for sure. Please keep doing videos like this.

[@hdm-nm]

It's a shame that Jeep doesn't (yet) offer gears lower than 410s on the Gladiator like it does on the Wrangler. I just got a 2024 JLUR XR w/35s and 4:88s, and I love it. So much low end power, and the 3.6 finally feels like it has grunt. So I can see why you'd want 513s with 37s on the Gladiator for sure.

[@DUNEATV]

I have the same…a 2024 XR it’s amazing!

[@blakemarchand6650]

Yeah you got a nice setup that sounds fun as hell

[@leegarrett1561]

Just picked up my JT from the shop today. Doing the break in, but the 5.13s already seem like they were the right choice. Thank you for helping me make that decision.

[@SteveH98264]

I've had 4.88s in my 22 JT Rubicon for nearly 2 years. I run a fairly light weight 35" tire (Toyo Open Country AT IIIs) and average 17 mpg for 90% of my driving. I actually get slightly better MPG now than I did with the stock 33s and 4.10 gears. I can see where 5.13s with 37s would be worthwhile.

[@MichaelApodaca]

This is great information! Thanks for sharing your experiences with stock 4.10s, the 4.88s and where you'd wished you went with 5.13s. All helpful for those of us with stock 3.73s upgrading our tires and weighing through all of the feedback online.

[@adrianw3985]

I was eventually thinking 4.88s on mine, but you got me thinking 5.38. I was talking to Exodus 4x4, and they recommended 5.13, honestly there isn't that much of a difference to just go 5.38 when it comes down to it. I am just on 35-inch tires right now so no rush to regear at the moment.

[@ShaunsJeep]

Ali its alway nice watching ya. I live here in New Mexico in Abq and we have mountains all around us. I have a JTR with 37's km3 and love them winch number lift and still 4.10s. I really want to regear to 5.13s but it's going to set me about 3 stacks back. Thanks for always sharing.

[@davidcooper3957]

I have a set of Dynatrac pro 60s with 4:88 and a GM 6.2, 10 speed in my wrangler and with this combination it runs perfect even with all the poison spyder armor and 37”13.5 ridge grapplers

[@DrivingLine]

That sounds like an awesome set up!

[@Verb130]

Another excellent video. I have 38" Nitto Ridge Grapplers mounted on Icon Pro wheels on my 2021 JLU with a lot of heavy modes. I'm set on 5.13s.

[@DUNEATV]

Great video…

[@senditentertainment4361]

When I go to my junkyard axles and 40” trail grapplers, I’ll be doing a 5.38 🤘🏼. The manual transmission in the JKs need that little extra gear ratio

[@raymondforbes4295]

I am thinking through this for my 4xe. 37” MT Baja Boss AT. It has lots of torque so it does pretty well at 4.10 but I think I will go to 4.88.

[@appalachhaun_adventures]

I’m in Northeast TN. I have the 2020 Rubicon with stock wheels and 37x12.50 Falken Wildpeak MT’s. Stock 4.10 gears. 2” AEV lift that recalibrates for the new tire size. It doesn’t feel any different really. I’m at 18-19 MPG all day every day except on trails. After a day of a trail I’m at 16mpg. A couple days later and I’m back to normal 18-19mpg. I have no desire to regear.

[@ryandoyle4344]

For equal gearing,using 4.10- 33: 4.35- 35, 4.6- 37, 4.72- 38, 4.85- 39, 4.97- 40. (>rotating mass of tire, >mass from accessory, >rolling resistance of tire, >aerodynamic drag; Additional factors are not accounted for above)

[@Greg-oo1zm]

I remember hearing something (albeit unconfirmed) wrong on the Yukon 4.88s that some were defective. I was going to regear to 4.88 prior to hearing that. I decided to remain stock (22 JT Rubi), but u are not the only one that think 5.13 is the way to go. Im running the 37s trail grapplers right now but going to go 40s after some more axle upgrades. So for me 5.13 I feel would be a good median for the transition from 37s to 40s.

[@DrivingLine]

If you plan on going to 40’s, I would go ahead and go higher than 5.13. You’ll rev a little higher initially on the highway with the 37s, but you’ll be happy you did it when you move up tire sizes.

[@dadventuretv2538]

Great vid and timely. Your channel has been a huge help in my 3.6 JTR auto trans build out. I’m contemplating going from 35s to 37s at next tire change. Definitely will go 5.13s if I do, my baby is fat. LOL. I’m also going to switch out the Aluminum steering knuckles on my JTR with the either the Mojave cast iron ones or after market ones. But Question- will I need to adjust the driveshaft angle also? I’ve seen some vids that it can rub. I am running an AEV Dual Sport lift with the 3 inch high capacity springs. So it will only be one more inch of lift vs current. TIA for your thoughts.

[@DrivingLine]

One of the good things about the front axle disconnect is that you can throw a lot of caster at the front axle and it won't make a difference with the driveline on the highway. If you are worried about the front driveline hitting, I would recommend unloading your suspension fully to ensure that the shaft isn't contacting the front crossmember. For the rear driveshaft, you may find that you need a carrier bearing drop to prevent the driveline from vibrating. I haven't had to do this with my Gator Gladiator, but my flatbed Gladiator on 1-ton axles has aftermarket drivelines from JE Reel that take care of that issue.

[@dadventuretv2538]

@@DrivingLine roger. Thanks man. Super helpful.

[@brsnow225]

I don't mean to throw rocks or start fights at all, should have started with the 3.0 eco diesel. '22 JT Rubicon, all stock, '33 AT falcons, it's crawled over/through all I've pointed it at. And I can manage 25-27mpg when I'm not in the stuff.......

[@DrivingLine]

The last two modern diesels I owned had enough issues to make me never want to own another emissions equipped diesel again. For me, reliability is more important than fuel economy. To be clear, I’m not saying what you have is unreliable. I’m just saying my experience with the emissions equipment on these modern diesel engines has been terrible.

[@AKBRONCOSFAN007]

I’m curious what are your recommendations for those of us running the Ecodiesel. They come stock with 3.73s and 32 inch tires. I’m not using the JT as a wheeler or rock crawler. It’s my daily driver and as soon as I get it back from the dealer after three months waiting for parts for a recall repair I’m installing an AEV RT 2.5 inch lift with 34 inch tall tires. The JT model I have is the WILLYS Sport.

[@DrivingLine]

I don’t think you’ll need to regear with just a 34-inch-tall tire and the EcoDiesel. A 4.10 wouldn’t be worth the cost and a 4.37 might be too much gear if you are doing a lot of interstate commuting. From the small group of people that I know with the EcoDiesel, changing the differential gearing isn’t necessary until you get to a 37 inch tall tire.

[@davidwebster3510]

You might want to mention what you lifted it up to. Tires are one thing gearing is another but lifted trucks is also another and when you combine all three, you definitely get different situations and different mileage

[@DrivingLine]

The suspension lift impact is fairly small on the Gladiator. The aerodynamics are already terrible. The tire size, weight, and additional gear are all way more important in my experience. I’ve had multiple lift sizes on both of my Gladiators. It’s always been the tire size that made the biggest difference. Gator colored Gladiator in the video has 3 inches of lift and 38s for reference. Before that, it just had a 1 inch lift and same tire. MPG and performance was the same.

[@mikeclark5879]

I have 23 Overland with bfg 33’s. Wanting to go to 36’s. I have steel bumpers and 12,000 warn winch. Maybe a topper and roof top tent I in the future. What gearing would you recommend. I was kind of leaning towards a 4:56 ? Looking for mpg and performance? Thanks. Great video by the way,

[@DrivingLine]

I would go 4.88. The difference between that and a 4.56 is fairly minimal. The extra gearing will help compensate for the added parts better than the 4.56.

[@cwwcww7465]

I run an AEV JT 370 Rubi Diesel with H Cap springs and 37- 11.50s ..... I also run an AEV JL 370 Sahara Diesel with the same set up.... ( Daily ) You cannot beat the Nittos....in that size on these Jeeps....for OVERLANDING.............. IF YOU WANT TO ROCK CRAWL, GO DO YOUR THING.... The wider tires kill everything good about your vehicle and makes you have to do crazy stuff and spend much more money...... I should know, I have almost 300k worth of Jeeps sitting in my garage...... Its just that damn Jeep thing....can't shake it... The damn wife had to have a wagoneer...I snuck a set of Nittos on it, you know, for safety and traction....😂 We're all stupid for paying ridiculous money for these ridiculous things.....😂 but it fun...ain't it....

[@DrivingLine]

As someone who currently has two Jeep Gladiators and two Wranglers 392’s, I sympathize with this remark more than you know. 😂

[@nevilleguard3558]

Great video lots of good information. I’m thinking about a re-gear for my 22 gladiator diesel been thinking about 4.88’s it’s on stock gears now with 37s and really heavy with a AluCab on the back. Now I’m thinking maybe a 5.13 may be better. How much top end would you think it would loose? It keeps 8th now pretty well with the exception of heavy head on wind. My biggest problem has been engine overheat so shifting manually helps keeping the heat down which I think with the rehearing would help there as well

[@DrivingLine]

I don’t have much experience with the diesel platform in the Gladiator. I would opt for 4.88 or 5.13 to keep the engine RPM lower on the highway.

[@nevilleguard3558]

@@DrivingLine thanks

[@berner1749]

4.88 or 5.13s for a deisel gladiator on 37s with full-size spare and front winch bumper?

[@DrivingLine]

I honestly don’t have a lot of experience with the eco-diesel in the Gladiator. I believe Nitro Gear offers a 4.37 gear that is intended for diesel JTs and JLs with 37s. I would say 4.88 would be more than enough.

[@Shakshuka69]

Would you recommend 5.29s with 37s? Or should I just stick with 5.13s? I'd say highway mpgs are more important to me

[@DrivingLine]

Your RPM's will stay lower with the 5.13s, which will help with fuel economy.

[@branthalper1016]

Nice info! What wheel offset are you running with the 38x13.50?

[@DrivingLine]

Zero offset/4.75 inches of backspacing.

[@branthalper1016]

@@DrivingLine good deal! So no rubbing issues? I’m running a +1 (5.00 backspacing) was just curious if I could run a 38x13.50

[@DrivingLine]

The only rubbing I experienced that was an issue was with the stock front bumper. I have since upgraded to a stubby front bumper and it’s not a problem anymore.

[@blakemarchand6650]

What if you have 3.73s 38 inch Nittos and some body armor at 5k feet elevation?? BUT you have the 6.4 hemi ? Does the power from the v8 out way the 3.73s or is my transmission screaming for mercy ?

[@DrivingLine]

When I had the 38s on my 392, I definitely felt like it could’ve used a little bit more gearing than the 4.56. I know there are a lot of guys out there that might disagree with me on this, but I think the HEMI’s actually work better with a little bit more differential gearing. I don’t think I could justify re-gearing from 4.56 to 4.88. However, if I had your setup, I would probably move to a 4.88 gear. Especially at that elevation.

[@blakemarchand6650]

@@DrivingLine yeah I agree I think I would enjoy the benefit of a 4.88 I have thought about it as well, I just wasn’t sure if i wanted 4.56 or 4.88s but 4.56 is would probably not be a big enough difference to make the work/install worth it

[@jordanfields3402]

The 5.13s look so much weaker than the 4.10s. The fear is breaking teeth and having differential damage on a Dana 44. I would use 5.13s if that issue wasn’t my fear on my gladiator with 37s.

[@DrivingLine]

I believe the benefits of changing out the differential gearing outweigh that potential risk. I’ve been wheeling my Gladiators for years, and been on a lot of trips with other Gladiators and JL Wranglers. I’ve never personally seen a ring and pinion failure on either platform, but I’ve seen a lot of axleshafts break. I think that’s the bigger concern.

[@the_black_jeep]

I’ve got 37x13.50R20 trail grapplers on my 21 Mojave and still the stock 4:10’s and it’s always so windy here in the western prairie of Canada I never see 8th and rarely see 7th. I was 100% going to go with 4:88’s till I watched this. Strictly for pinion gear size girth but now I’m second guessing that.

[@DrivingLine]

I would go 5.13. I’m just not convinced that the pinion on the 4.88 vs 5.13 makes that much of a difference.

[@the_black_jeep]

@@DrivingLine I put 5:13’s in my 09 Sahara and run the same tires and have chewed up that Dana 30 pinion so many times. Been building super duty axles since 2020 haha to fix that. Guess I haven’t chewed up the rear Dana 44 pinion so should be safe right? Haha.

[@DrivingLine]

The Dana 44’s in the Gladiator are fairly robust. Aside from the FAD, I don’t think you would have much issue running a 37. They are much stronger ring and pinion wise over the JK Dana 30 for sure.

[@the_black_jeep]

@@DrivingLine 5:13’s this then, didn’t think about how much more robust the new axles are. Great video like always. 👍🏼

[@helix_helix]

How does all this change with a 6 speed manual behind the 3.6?

[@DrivingLine]

You generally need a little more gearing with the 3.6l and the manual. For example, a if I went 4.88 with an automatic, I would want 5.13 with the manual.

[@LukeEdward]

Mr. Ali, I’d love to hear your opinion on us guys with the 6-speed Gladiators. In fact, anyone who might be reading this, I’d love to hear from y’all. As I love my RubiGlad.

[@DrivingLine]

My experience with the manual and 3.6L has always been you want to go up one numerical gear set from what an automatic would be. For example, if an automatic would go with a 4.88, the manual should go with a 5.13.

[@ryandoyle4344]

Isn't 1st gear for manual is ~3:1, while 1st gear for auto is ~4:1?

[@DrivingLine]

The six-speed in the Gladiator has a 5.13 first gear ratio. The 8spd auto is 4.71.

[@graywolf.overland]

With 392/ecodiesel/4xe level of torque, what would be your suggestion for 37s? Given that 392 and diesel JL rubicons came with 3.73 stock.. Is 4.56 the right great for 37s on those three power trains?

[@DrivingLine]

I have 4.56 gears in my 2021 Wrangler 392 on 37’s and I think the gearing is perfect. The diesel would probably be better served with a 4.37, but I’m not sure if that Nitro Gear is still available. My approach with the 4XE would be similar to the 3.6L. It will benefit then most of those three platforms with higher numerical gearing. This is especially true once you zap the battery pack and you are running on gas only. I would prefer a 4.88 in the 4XE. Maybe even a 5.13 depending on build setup and elevation. For a while, you couldn’t program higher gear ratios into the 4XE. I believe they have this sorted, but I remember seeing it being limited to certain ratios.

[@SubashCanapathy]

@@DrivingLine Is the rationale on why you would choose 4.37 for diesel is rooted in the fact that it has too much low end torque? If thats the case that applies to 4xe too.. there is too much torque all at once and high numeric gears might get chewed esp given overall weight of the vehicle being close to 6000lb. When you zap the battery to 0% there is 20% reserve capacity set aside for normal hybrid operations - at that point the 4xe is just like a toyota iforce-max parallel hybrid and its "always" a hybrid producing the spec-ed Hp and Tq irrespective. The only time you will run the battery to excessive depletion and limp mode is if you are towing something uphill for a long stretch somewhere in colorado where the speed at which the demand is sipping out battery exceeds the speed at which it can regen (since you wont have any regen activity if you are constantly uphill). Apart from that edge case, you are always 370hp and 470tq.

[@DrivingLine]

The diesel rationale is simply to keep the RPMs lower. It makes plenty of power at low RPMs and will retain fuel efficiency that way. My experience with the 4XE is more limited. But, based on the powertrain, shops I work with, and experience conversing with 4XE owners, the general consensus is that airing on the side of more (higher) differential gearing is better.

[@ducnut]

“Rat Extortionist”. 😂

[@monette44]