35's and re-gear dliemma

6

64Chevy

New member
This is one of those difficult questions to ask, and I'm open to all responses, but I'm really looking for owners of 3.6 JKU Rubis with autos running 35's and stock gearing.

I've got a 2015 JKUR with worn out 33 Duratracs. My rig is so heavy (winch, bumpers, skids, tools, recovery gear, etc.) that my TeraFlex leveling lift is down an inch from where it was (both front and rear).

Part of me wants to redo the lift big time (progressive springs, steering correction--the whole 9 yards) and go with 35s. But, I don't want to spend the money to regear, unless there is no other option.

So if you have a rig similar to mine (a 3.6 auto porky JKUR), and if you are running 35s, and have stock gears, is your highway power:

1) Essentialy as good as stock,
2) Okay, not great, but not worth the cash to regear, or
3) Embarrasing, and I wear a bag over my head when I drive?
 
EDIT: just saw you have a 3.6 Rubi so you have 4.10s. Need sleep. [emoji12] With 4.10s you should be fine on some 35s. But as I’ll say below, if it’s not up to the way you like your Jeep to drive then save up and regear down the line.

Now I am answering this in a completely subjective way, because I think how much power you need is subjective to the driver of the Jeep and your opinion on what feels good to you. But I’ve all three of the gear ratios offered in the JKs above with 35s, and I have to say the only one I found it to be unbearable was the 3.21s, and I’ve had all of em. It was extremely sluggish, and just had a heavy feeling. Now, that doesn’t mean it isn’t doable until you can save up for a regear. I just didn’t care for it.

If it were me, and I were in your shoes, I’d rebuild the lift and go with some good stuff, and go for 35s. Take your time and get a feel for how the Jeep drives with the new tires, and in that time save some spare coin (if you can) and regear. And if you don’t feel like it needs a regear, well then you have some extra cash for more parts.

Hope this helps!


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Your profile says you have a JKUR, so looks like 4:10s. Plenty of people have run 35s on those without a regear and been ok. Your transfer case will make up for a lot on the trail.
 
I run 35s with 4:10s no issues.
I can’t remember exactly, but isn’t it only manual rubicon’s that come factory with 4:10s? Autos have to be ordered with them? 🤷*♀️


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4.10 w/ 35’s are not as good as stock... but there is no need for an immediate re-gear. It’s fine. The engine will work a little harder at take off and pulling grades. But it’s Not a big deal. I will probably jump to 4.88’s eventually.
 
I’ve got a ‘12 JKUR auto on 35’s with 3.73 gears. I’m pretty happy with it and have no plans to regear. It’s night and day difference compared to the 3.21 gears. The transmission will bog and down shift on me from time to time but again, quite a bit better than 3.21’s. Your 4.10’s would be even better! My previous Jeep was a ‘95 YJ 4 cyl, so This JKUR is like a Cadillac!

With all this said, I would like to drive a jk with 4.56 or 4.88 gears for comparison. Maybe mine is a case of I just don’t know what I’m missing!!!


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black pearl said:
I run 35s with 4:10s no issues.
I can’t remember exactly, but isn’t it only manual rubicon’s that come factory with 4:10s? Autos have to be ordered with them? 🤷*♀️


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Click to expand...

If I remember right, the factory changed around 2014 or 15 from having 4.10’s paired with the auto trans as standard to 3.73 with the auto. Prior to that all Rubicons , auto or manual had 4.10 standard.
 
I feel like I have the same setup as you except for I have a 2.5 inch lift. 35s, 2016 rubi, auto, stock gears, heavy skids, sliders, bumpers.

The Jeep drove OK after the larger tires. I could tell that is wasn't shifting as well especially on hill climbs. I did end up getting a Superchips FlashPaq to adjust my tire size and speedo. IMO, when you move to 35s this is a must do.

I have also noticed that power is lacking on steeper grades. I am going to Colorado for a 5 day off road trip in August and will probably really feel the pain in the mountains. Overall, it is completely doable but you will want to eventually upgrade your gears. So the answer to your question would be #2.

64Chevy said:
This is one of those difficult questions to ask, and I'm open to all responses, but I'm really looking for owners of 3.6 JKU Rubis with autos running 35's and stock gearing.

I've got a 2015 JKUR with worn out 33 Duratracs. My rig is so heavy (winch, bumpers, skids, tools, recovery gear, etc.) that my TeraFlex leveling lift is down an inch from where it was (both front and rear).

Part of me wants to redo the lift big time (progressive springs, steering correction--the whole 9 yards) and go with 35s. But, I don't want to spend the money to regear, unless there is no other option.

So if you have a rig similar to mine (a 3.6 auto porky JKUR), and if you are running 35s, and have stock gears, is your highway power:

1) Essentialy as good as stock,
2) Okay, not great, but not worth the cash to regear, or
3) Embarrasing, and I wear a bag over my head when I drive?
Click to expand...
 
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black pearl said:
I run 35s with 4:10s no issues.
I can’t remember exactly, but isn’t it only manual rubicon’s that come factory with 4:10s? Autos have to be ordered with them? 🤷*♀️


Sent from my iPhone using WAYALIFE mobile app
Click to expand...

If I remember right, the factory changed around 2014 or 15 from having 4.10’s paired with the auto trans as standard to 3.73 with the auto. Prior to that all Rubicons , auto or manual had 4.10 standard.
 
TrailHunter said:
4.10 w/ 35’s are not as good as stock... but there is no need for an immediate re-gear. It’s fine. The engine will work a little harder at take off and pulling grades. But it’s Not a big deal. I will probably jump to 4.88’s eventually.
Click to expand...
^^^This.
You will notice a little slower acceleration and more down shifting on steep grades, but not intolerable. Don't let that stop you from a better lift and 35s.


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When I bought my Jeep it had 4.10 with 35’s it was fine you really noticed a power loss on hill climbs. So I re-geared to 4.88 and it’s was amazing how much of a difference. Transmission would hardly down shift, went up hills like nothing. Really noticed a difference to when out playing in the dez and rocks.


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tastethebeast said:
I feel like I have the same setup as you except for I have a 2.5 inch lift. 35s, 2016 rubi, auto stock gears, heavy skids, sliders, bumpers.

The Jeep drove OK after the larger tires. I could tell that is wasn't shifting as well especially on hill climbs. I did end up getting a Superchips FlashPaq to adjust my tire size and speedo. IMO, when you move to 35s this is a must do.

I have also noticed that power is lacking on steeper grades. I am going to Colorado for a 5 day off road trip in August and will probably really feel the pain in the mountains. Overall, it is completely doable but you will want to eventually upgrade your gears. So the answer to your question would be #2.
Click to expand...

Anytime you change tire size you need to adjust for that to get the speedometer and shift points back to normal.


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sipafz said:
If I remember right, the factory changed around 2014 or 15 from having 4.10’s paired with the auto trans as standard to 3.73 with the auto. Prior to that all Rubicons , auto or manual had 4.10 standard.
Click to expand...

I couldn’t remember specifics. I just remember reading that someplace, when I was researching to buy mine. But mine is a 16, so I was looking after the change
 
You already have 35s on your radar, so do it or later you'll be pissed off that you didn't. You can reassess the regear after that.

You may want to add C Gussets to your front axle as well, cheap insurance.
 
WJCO said:
You already have 35s on your radar, so do it or later you'll be pissed off that you didn't. You can reassess the regear after that.

You may want to add C Gussets to your front axle as well, cheap insurance.
Click to expand...

That. Drive it, and see how you like it. If it weren’t for the fact that I was going to tow a travel trailer, I wouldn’t have re-geared. I could live with it, otherwise. It isn’t a sports car.


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My 2016 JKUR automatic trans came with 4.10s out the box. I live in Colorado and run 35x13.50s through mountain passes. It dogs more, but it works. I’m looking forward to the flash cal action, haven’t done it yet. Don’t think I’ll make another gear change until it’s time for new axles

EDIT: I welded C gussets in as well. Happy I did, just looking at those poor little D44 C’s reaching out at my tires

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