35's on gladiator...regear?

[Secretariat]

So ... recently bought a 2021 used (40k) JT Rubicon (not diesel)...8 speed auto trans... lifted it 2.0 inches (Mopar)...put on some 17 inch black rhino wheels and 35 inch mud tread nitto's on it...and driving around town it drives great.. look good too. On highway...well...it sucks...wont leave 6th gear and slight hill bogs down or will down shift to 5 or even 4th...I honestly can not believe that the 4.10 gears can handle the set up....but I read so many post that claim "no worries...4.10 is fine no need to regear"....then I read post that say...at least 4.88 and if you not a speed freak (e.g. enjoy driving at 80 mph) you could actually go as high as 5.12. So if you have something similar to my set up and drive a bit of highway on your daily commute I would live to hear from you.

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[Redleg37]

Gearing is going to depend a lot on your personal preference and the topography of where you drive your gladiator.

I have a JK Wrangler on 33's with 3.21s. According to most internet wisdom it shouldn't be drivable at all. It works for me.

Some people will be happy with 35s and 4.10s, others will not be.

 

[Freems]

Mine is set up with 3:73s and 35s, I tow a 18’ boat and a 18’ car hauler trailer and they pull just fine. An eight speed transmission, by design will change gears for the load required, if you don’t like what’s it doing in that scenario, shift it to manual mode. I have a serious rule on any vehicle I own, if it can’t do the speed limit (80 mph) it can’t stay at my house. If your a full time rock basher with 40s, you need to re-gear to use all that tire investment $ for your purpose intended. IMO

 

[JT1]

That tire and wheel combo is heavy. Depending on your terrain and driving style, anywhere from 4.56 to 5.13 will work. Changing from 4.10s to 4.56s isn't much of a change. 5.13s may be massive overkill if you never plan on 37s...

 

[AmishMike]

NO!
I run 35's on my stock 2020 Rubicon, off-road, pull trailer etc.. I drive 40 miles/day highway 25/day on back roads. Nearly 70K on the truck, pulled campers from Pa. to Florida etc..
Get used to the truck first, expect 18 mpg highway and be excited when you beat that. 11 mpg if towing.
Re-gear helps with 1st-2nd gear, after that, the tranny will find the right gear.
You have opened a can of worms. Search and find old threads on this, there are a lot of charts and graphs on tire size vs. rpm etc..

 

[ShrimpHappens]

No you're right, everyone on here says 4.10's are fine with 35's. And Jeep themselves just puts 4.56's on 35's on the Wrangler XR, not even all the way to 4.88.

Have you used a programmer to tell the computer you're on 35" tires? That's a key part of the equation.

 

[PuddleJumper]

So ... recently bought a 2021 used (40k) JT Rubicon (not diesel)...8 speed auto trans... lifted it 2.0 inches (Mopar)...put on some 17 inch black rhino wheels and 35 inch mud tread nitto's on it...and driving around town it drives great.. look good too. On highway...well...it sucks...wont leave 6th gear and slight hill bogs down or will down shift to 5 or even 4th...I honestly can not believe that the 4.10 gears can handle the set up....but I read so many post that claim "no worries...4.10 is fine no need to regear"....then I read post that say...at least 4.88 and if you not a speed freak (e.g. enjoy driving at 80 mph) you could actually go as high as 5.12. So if you have something similar to my set up and drive a bit of highway on your daily commute I would live to hear from you.

I drive all over the mountains here in the East coast with 37s and 4.10s I still see 7th gear cruising and still see 8th. I only float in 6th when towing on 33s. I would like to go 4.88s when my 33s wear out so i can run 35s to tow and get a bit more torque out of the 37s. In your case i feel like your just leaning into the peddle a little hard so the trans is just keepin you in the power band. or you got some heavy ass wheel and tire combo. seen some guys running 140 lbs a corner and wonder why it bogs so hard.

 

[Lunentucker]

Many of the Black Rhino wheels have negative offset, so you may have put a lot of luggy tread on the MT's out in the wind, especially with the lift and perhaps a stubby bumper?

Stock Rubicon wheels are +44 mm offset.
If you bought Abrams they're what, -13?

BR does have some +30 offerings that make much more sense for Mojaves and Rubicons.

I run 2" lift and BFG K02's on stock rims, and I get 18-19 MPG and see 8th gear frequently at highway speeds.

 

[PuddleJumper]

Many of the Black Rhino wheels have negative offset, so you may have put a lot of luggy tread on the MT's out in the wind, especially with the lift and perhaps a stubby bumper?

Stock Rubicon wheels are +44 mm offset.
If you bought Abrams they're what, -13?

BR does have some +30 offerings that make much more sense for Mojaves and Rubicons.

I run 2" lift and BFG K02's on stock rims, and I get 18-19 MPG and see 8th gear frequently at highway speeds.

I didn't think about that. You and I run our Mojave's pretty tucked

 

[Lunentucker]

I didn't think about that. You and I run our Mojave's pretty tucked

Looking for a better word ?

 

[Dryfly24]

I have almost the exact set up on my Rubi - 2” Mopar lift and 35” Geolandar MT’s - with zero issues, so I’m as confused as you.

Mine shifts fine on the highway, with the speedometer being a couple miles under true speed according to those automated radar speed check devices.

 

[Josh00333]

OP you're 100% right the 4.10's are fine crowd are full of it

35's need 4.56 or 4.88's if you ever think you may go 37's. I'm re-gearing because 4.10's don't cut it.

 

[Trollboogie]

Did you program for the change in tire size? Also, the rolling mass or weight of you wheel and tire combo will make a difference. I have 35's on my Mojave and it does just fine. My setup is less than 100 lbs.

 

[Rahkmalla]

OP you're 100% right the 4.10's are fine crowd are full of it

Cool that your opinion is the only one that matters.

Anyway, i'll full of it too apparently. 6MT, 37lb steel wheels, 63lb Kenda Klever 315/70r17s. i see 6th gear just fine above 65 for cruising. a double downshift into 4th is required for any passing situation, but that's not crazy for a double overdrive manual.

 

[Firecop]

I'm running the stock Willis wheels which I like with 35 X 10.50 Ridge Grapplers and 373 gears (I think). I see 7th and 8th on the interstate regularly, of course I live in MS so we have hills, but not like other areas. I would guess that the narrow profile on the tires and them being under the fender wells reduces the drag some.

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