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Lifting my Jeep to a 3.5 and getting 35s

Mprehm

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I have a basic stock Jeep right now (smoky mountain edition). I’m wanting to get a 3.5 lift and 35s. I’ve heard about having to rehearing and getting a stabilizing bar… to fix the issues that comes along with the upgrade. Do I have to get all that if I’m lifting it to 3.5 and getting 35s? I need help!!
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JasonInDLH

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I have a basic stock Jeep right now (smoky mountain edition). I’m wanting to get a 3.5 lift and 35s. I’ve heard about having to rehearing and getting a stabilizing bar… to fix the issues that comes along with the upgrade. Do I have to get all that if I’m lifting it to 3.5 and getting 35s? I need help!!
On my JLUR I went with an AEV 2.5 DualSport lift. I added an adjustable JKS front track bar to recenter the axle. The stock Rubicon 4:10 gearing works perfect with my 35’s and 8 speed auto on and off-road IMO. I wouldn’t want taller gears with the 35’s.
 

Some Random Guy

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I have a basic stock Jeep right now (smoky mountain edition). I’m wanting to get a 3.5 lift and 35s. I’ve heard about having to rehearing and getting a stabilizing bar… to fix the issues that comes along with the upgrade. Do I have to get all that if I’m lifting it to 3.5 and getting 35s? I need help!!
Do you mean regearing and sway bar? Most lift kits come with the proper length sway bar end links if that’s what you mean. Regearing is a non-issue on 35’s.
Is there a reason you’re not going 2.5”? 3.5 introduces front driveshaft issues on a 4 door and issues with both front and rear pinion angles (driveshaft issue) on a 2 door if you aren’t careful about selection. They can probably be ignored, but if you get wild Offroad it will eventually bite you. Also, if you meant trackbar earlier the 2.5 will make it less of an issue. Adjustable trackbars do allow you to center the axles though.
 

engineXI

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Didn't hear about the Smoky Mountain edition, but it sounds cool as heck.

For regear, there is a formula: current gear ratio X desired tire size / current tire size. I think that if the result is really far from the current gear ratio, then you should regear.

3.5" lift is a big lift. get the track bar.
 

AVGeek99

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I have a basic stock Jeep right now (smoky mountain edition). I’m wanting to get a 3.5 lift and 35s. I’ve heard about having to rehearing and getting a stabilizing bar… to fix the issues that comes along with the upgrade. Do I have to get all that if I’m lifting it to 3.5 and getting 35s? I need help!!
Neither a regear or stabilizer bar are required for a 3.5" lift and 35s. However your jeep will handle and steer noticeably better with an adjustable track bar.

As far as regearing goes you can definitely do that later, or not at all if you don't want to. But with a stock non-Rubicon JK you will likely notice a decent loss of power with the 35s.

Do you know what your current axel ratio is? Smoky Mountain came standard with 3.21 gears, 3.73s were an option. Also do you have an auto or manual transmission? If you have a manual transmission and the stock 3.21 gears I would highly recommend a regear to at least 4.10s or 4.56s at some point. Drive it on the current gears and see how you like it.

My manual transmission JK had 35s and the stock 3.21 gears when I first got it. It was more or less perfectly drivable with that configuration, but it had no power. 6th gear was useless, it would hold highway speed on a perfectly flat road with no headwind. Add any incline at all or the slightest headwind and it wouldn't hold speed, NO exaggeration. So I just used it as a five speed.

First gear was fine on road most of the time. However, it had some difficulty starting from a stop on steep inclines, talking on road, not off. This is why I ended up regearing. I went with 4.56s. After that regear it was a completely different Jeep. I had all the power I ever needed in both 1st and 6th gears. It had power to accelerate (slowly) on the interstate in 6th gear. It cruised very nicely at 85.
I took it out West this past spring and it would hold 65 or better in 6th gear on most interstate mountain passes, occasionally I'd have to downshift to 5th, but rarely. In 2018 when I had the 35s and 3.21s some interstate mountain passes I'd have to drop all the way to third, semis would occasionally pass me.

So drive it with the 3.21s and 35s and see how it feels, but I'm guessing you'll want to regear.

If you have the 5spd auto I don't know how it handles 35s on 3.21s, but I'm guessing the experience will be similar.

If you have the optional 3.73s it may be more acceptable, but 4.56s are the way to go with 35s on a JK, at least with the 6spd manual.
 

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You sure you have a JL? The Smoky Mountain Edition was a JK edition. Most of this still applies however. As AVGeek said, you’ll want to regear most likely depending where you live/travel too. I went from 3.21 to 4.56 in my old JK and it was significantly improved. In the mountains not quite as much, but still had to better than the 3.21 stick gears.
 

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Didn't hear about the Smoky Mountain edition, but it sounds cool as heck.
It's a JK. Unless there is a dealer out there making their own/fake packages, it happens.
 

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I have no idea how things might fall differently on a JK, but I have a 2.5" lift and 35s on my JL, and that is plenty of lift. Anything more would be comical. I wouldn't do a 3.5" lift unless I planned to run 37s.
 

AVGeek99

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I have no idea how things might fall differently on a JK, but I have a 2.5" lift and 35s on my JL, and that is plenty of lift. Anything more would be comical. I wouldn't do a 3.5" lift unless I planned to run 37s.
There are fairly large differences between JKs and JLs especially when it comes to gearing, both in the Diffs as well as Transmissions. In the powertrain the 3.6L is about the only thing JKs and JLs share in common.

Both JK and JL Rubicons also share 4.1 diff gearing. All other JKs had 3.21 diffs standard and 3.73 was optional. In the remainder of JLs the standard diff gearing depends on your engine type. 3.6L and 2.0L both come with 3.45s. The diesel and 392 Rubicons both com standard with 3.73. The XR package comes with 4.56s. For 2022 4.88s currently appear to be a stand alone option for the 6spd Rubi, but at some point should also be available on the XR package with the 6spd manual.

The auto transmissions between the two are completely different, 5spd in the JK and 8spd in the JL.
Both JK and JL manual transmissions are 6spds but they are geared differently. With the JK 6spd 1st gear was rather tall, which doesn't work well with larger tires if you have the stock 3.21 gears. It's useable until you get on steep hills (think San Fran). In the JK 6spd the gears get shorter (as compared to the JL) as you go up.

In the JL 6spd 1st gear is on the shorter side. Running 35s on both rigs, in a JL with standard 4.1 Rubi diffs 1st gear is about equivalent to 1st gear on a JK with 4.56 diffs; the JL is actually a hair shorter. Then as you go up through the gears the JL transmission get's taller as compared to the JK. 4th gear in the JL is equivalent to 5th in the JK. 6th gear in the JK is actually geared closer to 5th in the JL than 6th.
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