37 vs 38’s and 4.88 vs 5.13

[gearhead22]

Hello all, I’m currently running a 3.5” lift and 37” bfg’s with stock 4.10 rubicon gears. It’s bearable but not ideal. Hunts a bit on the highway. Looking at rehearing to 4.88 or 5.13 and also possibly changing to a different 37 or stepping up to a 38. I mainly daily drive this, very little offroad use. I would say I’m more concerned with onroad drive ability vs offroad performance. I lean towards 4.88 because of this.

also, are there any required upgrades for 38’s over 37’s? Or are they basically the same in terms of stress?

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[Zachanadandy]

Stress on the drivetrain will be similar if you go with a light 38 like a milestar. Go to something like the nitro ridge grapplers that are 20lbs heavier and there will be quite a bit more stress. Enough to make a difference in breaking shafts or anything? Probably not for mostly road use. It's stick with 4.88s but we drive western freeway speeds of 80-85mph regularly.

 

[gearhead22]

Stress on the drivetrain will be similar if you go with a light 38 like a milestar. Go to something like the nitro ridge grapplers that are 20lbs heavier and there will be quite a bit more stress. Enough to make a difference in breaking shafts or anything? Probably not for mostly road use. It's stick with 4.88s but we drive western freeway speeds of 80-85mph regularly.

Nitto does have a c rated ridge grappler in 38 that’s the same weight as milestar but they’re quite pricey. If I go 38 I’d likely end up at the low 80’s in tire weight. Which some heavier 37’s are at that same weight. My freeway speeds are typically 70-75. Here in NY you’re not likely getting away with more than that lol

 

[Jrgunn5150]

Always go more, no one ever went 5.13 and wished the had 4.88, only the other way.

I'm driving around with 4.88's on 33's lol.

 

[Billyj7175]

I went with the 4:88's on 37's and then went to 38's. It's still good on the highway, but I have a 7X14 enclosed trailer. It does okay in the flatlands of Oklahoma, but it would seriously struggle in the mountains. If I could do it over, I'd go 5.13's for sure.

 

[Zachanadandy]

Always go more, no one ever went 5.13 and wished the had 4.88, only the other way.

I'm driving around with 4.88's on 33's lol.

False. Went 5.38s on our JLUR when we went to 38s and it was shit. 8th gear at any speed over 40mph. Lost 2-3mpg on the freeway. The gearing was better with 4.10s and 37s. Biggest waste of $3k I've ever put into a Jeep. If you don't drive freeway speeds and its a dedicated rock crawler then go deep. If you want to roadtrip the Jeep and still be able to rock crawl there absolutely is such a thing as too deep.

 

[gearhead22]

I went with the 4:88's on 37's and then went to 38's. It's still good on the highway, but I have a 7X14 enclosed trailer. It does okay in the flatlands of Oklahoma, but it would seriously struggle in the mountains. If I could do it over, I'd go 5.13's for sure.

What 38’s are you running?

 

[Zachanadandy]

Nitto does have a c rated ridge grappler in 38 that’s the same weight as milestar but they’re quite pricey. If I go 38 I’d likely end up at the low 80’s in tire weight. Which some heavier 37’s are at that same weight. My freeway speeds are typically 70-75. Here in NY you’re not likely getting away with more than that lol

The 39" kanati mud hogs on my wife's JLUR are E rated and still only 85lbs. I don't know if nitto used lead in their rubber compound or what but their tires are heavy.

 

[Roger2486]

My son has a 2021 JLU Rubicon on 37's...running 5:13 gears and loves on and off road, especially as he tows an overland trailer to set up basecamp, prior to adventuring. I am running a 2021 JT Rubicon set up for overlanding with a Four-Wheel Campers Project M topper...on the heavy side with water, gear, etc., on 37's, running 5:38 gears. Absolutely love the set up, return of torque and 8th gear on the highway...just got back from a 3200 mile adventure in CO, UT, AZ, and NM, 500 miles of which were off-road / trails and she was a beast. I would go deeper in the gears as others have stated; I have no regrets. Good luck!

 

[Billyj7175]

What 38’s are you running?

Milestar Patagonia MT02's on true beadlocks. Probably not the lightest tire/wheel combo out there. Lol

 

[Teh_Stormtrooper]

5.13 and 37s on my daily driven Mojave. No complaints here.

 

[gearhead22]

5.13 and 37s on my daily driven Mojave. No complaints here.

Patagonias aren’t terrible on weight, but the beadlocks could be lol

 

[Deleted member 67086]

Nitto does have a c rated ridge grappler in 38 that’s the same weight as milestar but they’re quite pricey. If I go 38 I’d likely end up at the low 80’s in tire weight. Which some heavier 37’s are at that same weight. My freeway speeds are typically 70-75. Here in NY you’re not likely getting away with more than that lol

Glad to see you’re looking at tire weight. In my opinion, as long as you keep tire weight within reason, are not pulling a trailer regularly, or Overlanding (aka overloading), I would think 4.88’s would be fine.

 

[Panthers65]

5.13 and 37s on my daily driven Mojave. No complaints here.

Me too, but on a max tow. 5.13's and 37" BFG ATs. Great combo, I'll typically average 18mpg to the tank, and will pull my 5K boat very comfortably.

 

[Stan H]

Hello all, I’m currently running a 3.5” lift and 37” bfg’s with stock 4.10 rubicon gears. It’s bearable but not ideal. Hunts a bit on the highway. Looking at rehearing to 4.88 or 5.13 and also possibly changing to a different 37 or stepping up to a 38. I mainly daily drive this, very little offroad use. I would say I’m more concerned with onroad drive ability vs offroad performance. I lean towards 4.88 because of this.

also, are there any required upgrades for 38’s over 37’s? Or are they basically the same in terms of stress?

Well since its just a daily driver I think I would just go with 5.38's since your put put put putting around town can just go slow and wave at the pedestrians

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