35's on gladiator...regear?

[DailyMoparGuy]

OP, definitely check the tire size calibration and go from there. I don’t know where you live, but it’s pretty hilly where I am and I regularly see 8th gear on the highway (central Massachusetts). That includes trips to New Hampshire’s White Mountains, Pennsylvania, Vermont, etc.

That being said, yea it downshifts to 5th on steep grades or 7th sometimes for slight grades. I wouldn’t expect anything less for any vehicle going up steep grades (except EVs obviously). If I set cruise at 75 mph, the transmission does it’s magic up grades and it stays at 75 mph with no issues (no bogging from a speed standpoint).

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[JamesWyatt]

Like everyone else said, you must use a Tazer or other brand programmer to get the right size tire input into the system. It's a night and day difference as you will find out after having done so. In fact, after reprogramming, mine does better on steep grades at higher altitudes at interstate speeds than it did stock. The 4:10s with stock 33s would have to downshift too far and the engine would be screaming in same scenario.

 

[jmdusza01]

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 have 2021 overland. Put 2inch mopar lift on 10/22 and 35’s on1 year ago. I have been on the fence regarding rearing due to struggling at low temperatures and on highway. Ended up going with 4.56 Yukon gears after initially getting through the first 500 miles of easy driving had fluid change last Friday and the shifting is amazing. Shifting a smooth on the lower gears and easily into eighth gear not just for highway driving but for residential areas as well. Looking forward to hopefully seeing better fuel economy as well. Didn’t realize what a difference it would make.

 

[Lunentucker]

Just curious if anyone has had their tire shop adjust the new size.

I seriously doubt that any tire shop will do it. It's going to require a SGW bypass and a dedicated programmer married to your Jeep. I don't think there are any out there that skirt the marriage license.

 

[Gladiatorx2]

I have 37's with the same brand of wheels on 4.10 gears and for over 5,000 miles I have averaged over 29 mpg. It was programmed for the tire change.

19 not 29...typo.

 

[Bjeepz]

I wouldn't consider letting a tire shop attach a computer to my Jeep!

I felt the 35's on stock wheels on my Mojave with auto and 4.10's was great, the whole it doesn't stay in 8th gear all the time is because it shouldn't, any vehicle is going to downshift on grades. I didn't feel the need to get a programmer.

I am now in my new Mojave and have put on 37's, I'm noticing a significant difference in performance. Still on stock wheels, no spacers, the tires are light at 69lbs each. I will be ordering the AEV ProCal. I've read too many stories about the Tazer having issues and no support. That said I am open to all suggestions and information about the various products

 

[Lunentucker]

I wouldn't consider letting a tire shop attach a computer to my Jeep!

I felt the 35's on stock wheels on my Mojave with auto and 4.10's was great, the whole it doesn't stay in 8th gear all the time is because it shouldn't, any vehicle is going to downshift on grades. I didn't feel the need to get a programmer.

I am now in my new Mojave and have put on 37's, I'm noticing a significant difference in performance. Still on stock wheels, no spacers, the tires are light at 69lbs each. I will be ordering the AEV ProCal. I've read too many stories about the Tazer having issues and no support. That said I am open to all suggestions and information about the various products

Look at ECRI before you do that. Super easy.

 

[chorky]

All these responses wont mean a crap if you don't provide some info on where you live.

How many have said you need 4.88's. How many have said you are fine with 4.10's and how many say 37's and 3.73 is ok.

Perspective is critical. Few have stated their road conditions, elevational changes, elevation, average temperatures, etc.. along with their tire/axle combination. That does EVERYBODY a disservice. You cannot expect to understand perspective without ALL of the information.

Example:
I live up north. In very hilly terrain. I have stock 33's 4:10 out back. I am heavy, with a 2.5" lift, a RTT, and solar panels. I have routine winds averaging 25mph with a 80mph highway limit - often times winds are going against me when also going uphill - meaning an effective wind resistance of 105mph on top of an uphill battle. ALL OF THIS MATTERS. The details are important to properly understand a situation.

I barely ever see 8th gear. Routinely I am in 5th going up a slight incline. I wish the JTR had 4.56 with the stock 33's. I would like to have 4.88's if I ever upgrade to 35's. It will keep the power band more balanced.

Those living down south with no hills and no mountains and no head wind and no weight in the bed, with no canopy, and no RTT will have a WILDLY different opinion. Details matter.

 

[JamesWyatt]

All these responses wont mean a crap if you don't provide some info on where you live.

How many have said you need 4.88's. How many have said you are fine with 4.10's and how many say 37's and 3.73 is ok.

Perspective is critical. Few have stated their road conditions, elevational changes, elevation, average temperatures, etc.. along with their tire/axle combination. That does EVERYBODY a disservice. You cannot expect to understand perspective without ALL of the information.

Example:
I live up north. In very hilly terrain. I have stock 33's 4:10 out back. I am heavy, with a 2.5" lift, a RTT, and solar panels. I have routine winds averaging 25mph with a 80mph highway limit - often times winds are going against me when also going uphill - meaning an effective wind resistance of 105mph on top of an uphill battle. ALL OF THIS MATTERS. The details are important to properly understand a situation.

I barely ever see 8th gear. Routinely I am in 5th going up a slight incline. I wish the JTR had 4.56 with the stock 33's. I would like to have 4.88's if I ever upgrade to 35's. It will keep the power band more balanced.

Those living down south with no hills and no mountains and no head wind and no weight in the bed, with no canopy, and no RTT will have a WILDLY different opinion. Details matter.

The overriding context for this thread is the OP hasn't updated their computer for the new tire size and seems to think they don't need to. Nothing else matters until they resolve that issue.

 

[Secretariat]

Have appointment tomorrow to have it done at dealership to have the change in tire size programmed in....stay tuned....

 

[Hootbro]

Have appointment tomorrow to have it done at dealership to have the change in tire size programmed in....stay tuned....

Need to ask your dealership if it is a one and done program or will they adjust the size up/down if needed to get it dialed in?

That is why most people get JScan or similar because it may take 2-3 times to get it right.

 

[JamesWyatt]

Need to ask your dealership if it is a one and done program or will they adjust the size up/down if needed to get it dialed in?

That is why most people get JScan or similar because it may take 2-3 times to get it right.

^ This. Make sure the work order is “Calibrate speedometer to match GPS by inputting appropriate tire size.” They have to be held to dialing it in.

 

[Stan H]

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.

Mine has 91,800 miles on it sitting on a 2.5 inch lift with 4.10's and mine is in 7th and 8th gear every day.. I live in WV and there isn't hardly a flat or straight road in this state.. if it is straight your either climbing or decending from one.. I don't understand why some won't handle it and why some will . Beats me .? I swear every word I just typed is true. This was 4000K after I stuck my 2.5"lift and 35'X12.50x17 on it .
That's what I get on Highway. On back roads I drop to 15.0 Because I am on and off the juice so much.

 

[Sigz]

Stupid question.

I have a Sport S with 3.73 gear ratio.

If I go from 33inch to 35inch tires - and RECALIBRATE my setup with JSCAN to input the correct tire diameter - how much and big of an issue will shift points be and MPG?

I'm sure I'll take a dip in MPG - but are these folks who are running 35's with the 3.73 gear ratio who are complaining of lack of fuel efficiency and shift points - are they missing the recalibrating steps?

 

[Hootbro]

Stupid question.

I have a Sport S with 3.73 gear ratio.

If I go from 33inch to 35inch tires - and RECALIBRATE my setup with JSCAN to input the correct tire diameter - how much and big of an issue will shift points be and MPG?

I'm sure I'll take a dip in MPG - but are these folks who are running 35's with the 3.73 gear ratio who are complaining of lack of fuel efficiency and shift points - are they missing the recalibrating steps?

3.73's and going to 35" tires may be a bridge too far in recalibrating for vehicle speed and expecting to see 8th gear with any regularity.

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