ok folks, need some help and quick like. have everything done and ready to go to pick up my new 2012 JKU tonight at 530pm and after doing some more looking I just realized that there is a difference between the tow group and the max tow group, namely the 3.73 gears. I plan on doing my lift and going to 35's within the next 3-4 weeks and need to know if anyone is running a 2012 with 3.21's, 35's and a 6 speed. I live in FL so its pretty flat here and i will be doing quite a bit of light to moderate offroading with no money to do gears in sight. Is this setup liveable? is it ok with the new motor? whats the skinny?

 

Not livable with 35's, you'll probably not be even able to use 5th and 6th gear with those tires. 35's with 3:73 gears is barely livable.

 

No real world experience (first Jeep) but based on what I have read here. I only looked at Jeeps 2012 (JKs) with 3.73, mines an auto with 35"s and it is noticeably. On the hwy its fine it's around town under 40mph that it feels like its lugging in to high a gear. This is after procal and that made a big difference. I would think it would only be worse with a 4dr, IMO not that it means much!

 

with 35's, you can do it. just make sure you calibrate your speedo with a procal and it'll be tollerable especially with the 3.6L

 

I have done a bunch more reading and this seems to be the general consensus. With most 35's actually measuring around 34" this would put me at around 1800 RPM according to the charts, and I know this is low, but if I stay in 5th gear I'm thinking I should be ok.

 

I bought a 2012 JKU Sahara Automatic with 3.21s and I have been kicking myself.

A) I should have bought a Rubicon
B) I should have at least opted for the 3.73s as it might have made things here in FL do-able with 35s

personally I am on the fence about just going with 33s for a while OR staying with my stock 32s for now and doing a re-gear, lockers and 35s all at the same time ( super wallet ouch).

My Teraflex 2.5 coil lift with Bilstein 5100s and JKS discos go on this weekend. I am anxious to see what it looks like with the stock Sahara wheels and 32" Duelers. I would love to get my hands on a set of take off or used 33s, but finding them in an 18" wheel size is impossible.

If I were you I would run 33s or re-gear before you go to 35s. Even with our new motor you will get sick of trying to find the power band.IMO Also keep in mind that its more than just inches you are trying to turn....its 50% more rolling mass. Plus if you have 17" wheels 33 take offs should be easy to find on Craigs list etc....

 

I have a 2012 Rubicon with 35's, manual transmission, and, of course, 4.10. It is perfect for me on road, maybe just a tiny bit low off road. I would definitely not want to go down at all with my gears. Although, I guess I would survive and still love my 35's if I did.

Hopefully this provides some bit of insight for you.

 

After reading other commits on people saying you can do it ,I'd thought I'd look at the numbers. Doing 55mph now with your currant tire and gear ratio your RPM is at 1850rpm's . Changing over to 35 inch tires with the same speed and gear ratio your rpm is 1600rpm. Now I know 200 rpm is not much different but I feel that 3.21 gear ratio is to low for that size tire and your going to find yourself constantly down shifting to keep the truck in it's power band. Just my thoughts, but I would not do it.

 

Well I decided not to do it after all. After talking it over with the wife, realized its gonna be at least 6months to a year before I can regear. I think im gonna be better of to get one that has the 3.73 gears.

 

Thanks! It's actually kinda funny, from the factory, its only like a $50 option to get the 3.73 gears over the 3.21's. What's even funnier is when the Sales Manager called and tried to push me into the sale, and after trying to explain to him how 3.73 gears were better for off-roading and for when I put 35" tires on. He literally spent 20 minutes trying to convince me otherwise, I finally had to flat out tell him that I wasn't talking to him anymore and that my original salesman was more than welcome to call me again, but he was not.