rtguy1

i'm running 35's now on stock 3.73's 2012 2 door and its manageable. my axles are being built now and evo is doing the full install when they are ready. i went with 4.88's in my new axles since i also ordered new 37' nittos at the same time. this was my own decision...not influenced by evo. i think 4.56 would be ok but still a bit lacking for 37's. great for 35's though. 4.88 should be a good balance. if i didn't hit the highway as much as i do i would have gone 5.13's. i think people act like the motor is fine without regearing because it does have alot of power. u are still lugging it when adding bigger tires. i will report back soon

chris@offroadevolution

its 200 rpms or so difference at 70 mph. Dont forget all the rotating mass from the 37's. It takes more to get them moving. I would go 5.13's.

As a matter of fact, thats what I will be installing on mine. I drive the freeway 60 miles plus a day. I did not buy a 2012 for the new motor only to lose the power from stock gears

Cam36

I have a 2012 2 door 6speed with 3.21s, I am going 35s and do not plan to ever go bigger, it's my daily driver with little offloading here an there, would you suggest 4.56 or 4.88s what would the rpms be at 75 mph?

powrsurg

I used this site to do my own comparisons.
MFactory Competition Products - Forged Transmission Components

As mentioned in numerous threads in the past this is how it works.

Lets assume you have jeep that came stock with 32in wheels.

2012 - 2013
If you move to 35 in tires you need to regear to 456 if you want stock 410 performance, or to 410 if you want stock 373 performance.

If you move to 37 in tires you need to regear to 488 if you want stock 410 performance, or to 456 if you want stock 373 performance.

2007 - 2011
If you move to 35 in tires you need to regear to 488 if you want stock 410 performance, or to 456 if you want stock 373 performance.

If you move to 37 in tires you need to regear to 513 if you want stock 410 performance, or to 488 if you want stock 373 performance.

bombout800

So there arent anymore issues with 2012s and gears? If i do 4.88 with 35's would that affect my highway mileage a lot verses whatever my factory gears are? Also would this hurt in city as well? IM getting around 14.5 avg mpg driving very cautiously to stay in eco mode. I run around 2300-2400@ 70 now IN a 2012 sport with 35 nitto mud grapplers.

danh63

I'm battling this issue along with a couple of others. I have a 3.21 auto and am lifting 2.5 to go 35's. never plan on going any higher or bigger. Mine more or less will see very mild trails and sand dunes mostly pavement. Being it is so pricey I am wanting to do it right the first time. At first I thought 4.10 would be good then I heard 4.88 and now wondering 4.56. Can anyone tell me the real deal?

BubbaJK2012

Installed a few leveling kits and 2.5 on a few 2012 and soon 2013.
Rode in a few That have 3.73 max tow package and 35's felt pretty good all around. This is an automatic though. Also rode in a Rubicon auto with 4.10 and 35's felt better for passing and such.
Lastly I rode in a Sahara Automatiac with 4.56 gears and pulling a small trailer and again was setup great.
I personally think if you are never going higher than 35's, never pull or haul anything a 4.10 setup would be fine or even 3.73

danh63

Thanks! Mine is a 2013 and auto. It had a 3.21 so I knew I would have to regear. Thanks for your input!

chris@offroadevolution

There was never any issue with it. You will need to run a AEV procal to adjust the gear ratios in the computer. Without one the 2012 will go into limp mode

You should consider 4.88's if your never planning on going over 35's.. Never say never on a tire size however

chris@offroadevolution

why lose the HP you gained on a 2012 3.6 penstar? might as well saved the money and went with the old 3.8 slow motor.
regearing is the most cost effective way to gain the power back after installing bigger tires.