Gear ratio poll for 37” tires on 17” wheels 3.6 gasser

[human29]

I ran 4:88's and it was perfect. I gained power and fuel economy due to putting the trans in the right gear. 5:13 are too big for the Dana 44 housings anyway.

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[JT1]

I ran 4:88's and it was perfect. I gained power and fuel economy due to putting the trans in the right gear. 5:13 are too big for the Dana 44 housings anyway.

Care to attempt an explanation?

They seemed to fit just fine in mine a few years ago..

 

[human29]

I ran 4:88's and it was perfect. I gained power and fuel economy due to putting the trans in the right gear. 5:13 are too big for the Dana 44 housings anyway.

Best mod and money I spent on the jeep.

 

[GI Grandpa]

Looking for consensus on ideal gear ratio for 37” tires. I just installed Mickey Thompson Baja Boss AT with my stock Mojave 4.1 gears. So far seems fine but curious what others have done. My Jeep is a daily driver and off road is fire roads or sand dunes no heavy rock climbing. I’m in Wisconsin so elevation is 700 and not a lot of hills.

4.88's if you're just driving/wheeling in WI, if you're towing 5.13 or even 5.38's

 

[Gabby53E]

Looking for consensus on ideal gear ratio for 37” tires. I just installed Mickey Thompson Baja Boss AT with my stock Mojave 4.1 gears. So far seems fine but curious what others have done. My Jeep is a daily driver and off road is fire roads or sand dunes no heavy rock climbing. I’m in Wisconsin so elevation is 700 and not a lot of hills.

I think you hit the nail on the head with where you live and primary use. I imagine 4:88s would work perfectly there with 37's just like the chart shows. I live in southwest Colorado and the extra oomph I get out of the 5:13's in the mountains is very welcome and allows the transmission to get to 8th gear on the highways out here. Although, on occasional trips to the flat midwest I feel a little over geared at highway speeds,.
My rig is a little heavier too with a Super Pacific camper and gear so that was also a consideration for me

 

[human29]

Care to attempt an explanation?

They seemed to fit just fine in mine a few years ago..

Not 100% clear on this but it was explained to me when I regeared mine that in order to do 5:13 gearing it needs to be made thinner in order to fit into the stock housing and they are very prone to breakage.

 

[Zachanadandy]

Local regears are $3k plus, half the cost of a procharger. The 8 speed has plenty of gearing, if you want more power, actually add more power. Holding 8th isn't the intent of 2 overdrives period. It's supposed to downshift under load. Made the mistake of going 5.38s on our 2019 JLUR on 38s and it wasn't better anywhere aside from reverse. It actually lost a half second 0-60 as the trans had to shift 1 extra time (2.0t with lower rpm redline). It lost 2 mpg over all and 2.5 on freeway roadtrips. Sure it held 8th all the time... like any speed over 40mph. What's the point of having 8 gears if you're in the top 1 by half the legal speed limit and no where to upshift from there?

 

[JT1]

Not 100% clear on this but it was explained to me when I regeared mine that in order to do 5:13 gearing it needs to be made thinner in order to fit into the stock housing and they are very prone to breakage.

Lots of people on here with them.. yes they may be marginally weaker, but that doesn't mean they are prone to breakage. 5.13s on a 33" tire is less prone to breakage than a 4.10 on 42's

 

[jmr]

So Jeep got it right having 4.10 gears with 33's. When I had my '22 Willys 2 door with a 2.0L A8 automatic I swapped for a set of takeoff Rubicon wheels/tires 33's. The Willys had 3.45 gears and felt somewhat underpowered at highway speeds having 4.10 gears would have helped.

 

[human29]

Lots of people on here with them.. yes they may be marginally weaker, but that doesn't mean they are prone to breakage. 5.13s on a 33" tire is less prone to breakage than a 4.10 on 42's

I for sure am no expert. I do almost all my own work but not the gears. I went to a shop to get 5:13 put in and he said if I want that to go some place else he would not do those on stock housings. He stated he does 2 a week on the regears and to go 4:88. I put over 40k miles on 4:88 and 37s and it was perfect. Mostly road driving and did great when I was lucky enough to get offroad.

 

[Warevelle]

Looking for consensus on ideal gear ratio for 37” tires. I just installed Mickey Thompson Baja Boss AT with my stock Mojave 4.1 gears. So far seems fine but curious what others have done. My Jeep is a daily driver and off road is fire roads or sand dunes no heavy rock climbing. I’m in Wisconsin so elevation is 700 and not a lot of hills.

I just put those tires on mine. Had already regeared to 5:13 and ran those on stock rubicon tires for a while before I got the tires. I couldn’t be happier with that ratio. I am set up for overlanding and typically run with 700’ish pounds in bed but perfect setup for my tire size and payload

 

[Wheelin98TJ]

Local regears are $3k plus, half the cost of a procharger. The 8 speed has plenty of gearing, if you want more power, actually add more power. Holding 8th isn't the intent of 2 overdrives period. It's supposed to downshift under load. Made the mistake of going 5.38s on our 2019 JLUR on 38s and it wasn't better anywhere aside from reverse. It actually lost a half second 0-60 as the trans had to shift 1 extra time (2.0t with lower rpm redline). It lost 2 mpg over all and 2.5 on freeway roadtrips. Sure it held 8th all the time... like any speed over 40mph. What's the point of having 8 gears if you're in the top 1 by half the legal speed limit and no where to upshift from there?

Some people just want to see 8th. Not hold it or always be in it.

 

[Clark]

I got a brand new set of dana-spicer ring and pinions in 4.88 with ds bearing kits, all new, 1000.00 shipped to you, I went a different route.

 

[Bjeepz]

I have 37's on my Mojave, still with stock 4.10's, no plan to ever change them as up here in Canada I would be looking at something insane like 5k. I do notice things are not quite as good as the previous Mojave that was on 35's. By not as good I mean shifting but I have been lazy and not corrected for the tire size yet. The Jeep does see 8th gear all the time though, sure it doesn't hold it but as a few others have said it shouldn't just sit in 8th on the highway at all times, the point of more gears is to be in the right gear for the setup at the right time. I have a 500km (300 mile) drive later today with a fair amount of hills for my province. I am expecting 13.5-14.0L/100km (about 19-20mpg). Last road trip I had my canoe on the roof and was in that range but it was flatter.

Do I wish I had the same feeling of power I had in my Rubicon XR with 4.56 and 35's? YES! I would have liked to try one of the factory optioned Rubicon's with 4.88's and stock tires to see how peppy that felt.

I appreciate the honesty some are stating about losing fuel economy when re-gearing.

 

[Sikjeep2]

Local regears are $3k plus, half the cost of a procharger. The 8 speed has plenty of gearing, if you want more power, actually add more power. Holding 8th isn't the intent of 2 overdrives period. It's supposed to downshift under load. Made the mistake of going 5.38s on our 2019 JLUR on 38s and it wasn't better anywhere aside from reverse. It actually lost a half second 0-60 as the trans had to shift 1 extra time (2.0t with lower rpm redline). It lost 2 mpg over all and 2.5 on freeway roadtrips. Sure it held 8th all the time... like any speed over 40mph. What's the point of having 8 gears if you're in the top 1 by half the legal speed limit and no where to upshift from there?

Agreed, I don't know why people obsess over 8th gear so much. The 8 speed is way better then the JK 6 speed. And the double over drive, 7th gear is fine at the correct rpm and can get good gas mileage.

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