So let me get this straight...?? (2012's and re gearing)

So, if I have a 2012 JK 4dr (with Pentastar engine)and I decide to run 35/12.5....I do not need to re gear my rig?? Please feel free to chime in on this one guys! :thinking::dont_know::confused::question::pop2::hmm:
 

rtguy1

New member
that would depend on the factory gearing ratio you have. 4.10's work fine for 35's, 3.73 is ok. 3.21 is poor even with stock tires
 

Philip *AZ*

Banned
Also, at least get an AEV Procal or the like to correct the shift points, tire size etc...


If you can't walk my beat unarmed, maybe you should consider becoming a police officer.
 

darkscion0

New member
I have a sport with 3.73 gears. If you got the tow package then you have 373

From what I can tell it seems like half way through the build year they changed it. First half of the year the tow package included 3.73 gears, second half they reduced the cost for the tow package and split out the 3.73 gears as a separate option.
 

Linebacker

Caught the Bug
From what I can tell it seems like half way through the build year they changed it. First half of the year the tow package included 3.73 gears, second half they reduced the cost for the tow package and split out the 3.73 gears as a separate option.

I believe you're correct on this. I ordered my 2012 JKUR last April w/4.10's and tow package thinking it wouldn't wear shoes any bigger than 35's.:twocents:
 

StrizzyChris

New member
Like mentioned above, you will need to get a procal to re-calibrate your speedo, and that will help with your shift points also. Get that and run the tires for a little while and see how much you like it. No matter what it wont cause any damage. Everyone's "need" to regear is different and you can be the judge for yourself. I am running 4.10 in my rubi and almost cant tell the difference from stock 32's
 

rtguy1

New member
I have a 2012 Sport so I believe the gearing is 3.21

sports can come with 3.73 or 3.21, with 3.73's you will be ok if you get a procal to adjust the shift points. I've rolled on 35's with 3.73's since i got my jk and its decent. Not enough loss to warrant the money to upgrade. 3.21's would not fly for me with 35's and i would upgrade. Now I have 37's going on and new my axles were built with 4.88's.
 

Skid_Kid

New member
I have a 2012 Sport so I believe the gearing is 3.21

My Rubi has 3.73's but so does my wife's Sport cause hers has the tow package. Try and get your build sheet from the link I just posted in another forum Brother.


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DasBuxxx

New member
Also the customer preferred package will get you 3.73 gears in a sport like mine came with.

Did it list the 3.73 on your build sheet. I have a 2012 JKU Sport from with the Customer Preferred Package 23s and am thinking i got 3.21 in mine...not for sure though
 

FeltsYouUp

New member
My sport came with 3.73s, but I don't have the tow package. I think they may have been part of the limited slip option, though I'm not 100% sure on that one. I plan on doing 35s and just recalibrating the speedo. I have a 6-speed as well, so I don't know how much that might help or hurt how the jeep feels around town. This is my DD, so if I'm happy with 35s then I'll hold of on gears until I'm ready to put some lockers in and all that good stuff.
 

OverlanderJK

Resident Smartass
My sport came with 3.73s, but I don't have the tow package. I think they may have been part of the limited slip option, though I'm not 100% sure on that one. I plan on doing 35s and just recalibrating the speedo. I have a 6-speed as well, so I don't know how much that might help or hurt how the jeep feels around town. This is my DD, so if I'm happy with 35s then I'll hold of on gears until I'm ready to put some lockers in and all that good stuff.

You'll be fine. That's the setup I run currently.
 

flotto

New member
Thanks for the input guys! I'm pretty certain I have 3.21 on my sport so I'll do the AEV Procal and consider upgrading down the line depending how my power feels.

that's the approach I took about a month ago. I added my 315s then lift with 3.21 gears on my 2012 JKU. I don't hate it, could I have more power at highway speeds sure. From 0-45 mph I don't notice much of a difference at all. regearing is on my todo list but there is a lot of mods before it.
 

Skirmish

New member
With an auto you can get away with 35's and 3.73. With a Rubi you can get away with 4.10 and 37's. With a manual Sport, 35's suck at 3.73. Mountains on the freeway are a problem, crawling rock is nothing but clutch smoke and the whole crawl mode is useless.

If you drive an automatic Wrangler I have no pity for you when it comes to lack of power on trails but a 2012+ stick without the Rubi transfer case should be running 4.88's with 35's. No question.
 

OverlanderJK

Resident Smartass
With an auto you can get away with 35's and 3.73. With a Rubi you can get away with 4.10 and 37's. With a manual Sport, 35's suck at 3.73. Mountains on the freeway are a problem, crawling rock is nothing but clutch smoke and the whole crawl mode is useless.

If you drive an automatic Wrangler I have no pity for you when it comes to lack of power on trails but a 2012+ stick without the Rubi transfer case should be running 4.88's with 35's. No question.

Really? I have a '12 with 35's and 3.73's, 6 speed and I have no problems crawling without the clutch smoke and driving freeways in the mountains. Yes while in the mountains I have to downshift but I can still keep it at 75-80 going up hills. I actually think it does better with the 35's on the trail because it goes a bit slower.
 

Skirmish

New member
Really? I have a '12 with 35's and 3.73's, 6 speed and I have no problems crawling without the clutch smoke and driving freeways in the mountains. Yes while in the mountains I have to downshift but I can still keep it at 75-80 going up hills. I actually think it does better with the 35's on the trail because it goes a bit slower.

Actually it goes faster. The tire will rotate the same number of times but since there is a bigger distance covered in every revolution you go faster. The trade off is power. With a properly geared newer JK stick you can take your foot off the gas and idle though rock washes without stalling. You can even ride the brake and it will keep moving. With 35" at 3.73 it will stall at the slightest climb.

The key to climbing big rock is control. With an under geared rig you have to ride the clutch to keep your speed down or you will start to break parts. It's okay on the freeway until you get to a steep hill and city driving sucks. I hated backing up my driveway as it felt like I was doing 30 in reverse with the clutch out.

If you had a bigger gear in the transfer case it would be acceptable but running big rock at that ratio sucks.
 
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