pnoman

Hi everyone this is my first post
just purchased a black 2012 rubicon unlimited i wanted a fully loaded one which i found.
The only option it did not have that i wanted was the 4.10 axle ratio, it has the automatic transmission if i wanted to order one with the 4.10 ratio it would have taken 8-10 weeks. My question is how much difference would the 4.10 make when i increase tire size to 35". Should i have waited? Anyone with a rubicon running 35's if so what lift are you using to keep or better the o.e.m ride.
Thanks

Ninemat

To my knowledge, every Rubicon comes with 4.10 rear axle ratio as a standard feature. 35" tires are heavy and 4.56-4.88 gears would make you keep all the power compared to original state but then less fuel economy. With the 2012 Pentastar 3.6L engine that develops 285 hp, it is certainly not mandatory to change gears right away especially if you spend more time on road than off road.

As per lifting your ride, you can run 35s with as low as 2.5 inch lift but might be rubbing the original fender flares under extreme offroad conditions. If you decide to go 4 inch, I suggest you spend the extra money to get a complete kit, not just coils and shocks. At least you get more strength since your JKU will obviously become heavier with all that new stuff you add on it. Again it all depends what you're looking for, a nice cool ride to look at or a kid's toy to go play in the mud!!

Enjoy the jeep!

IZA_JK

The 3.73 axle is standard on the automatic Rubicon for 2012 and 4.10 on the manual, 4.10 was standard on all Rubicon's for previous years. They say the automatic transmission with the new motor can handle the factory 32"'s with no problem. However, I agree with Ninemat, you should just swap out to 4.56 or higher if you want to run bigger tires. It will let you keep some of that new power, while you're at it you just may want to splurge and get a much heavier (weight wise too) Dana 60 if you plan on doing some serious off roading.

DCjeep

A Dana 60? Come on guys lets be realistic here.


Get the 4:10's. They will be more than enuf to run the 35's. We have a guy in our club that has a 2012 jku and runs 35's, metal bumpers, sliders. He has no complained once about the power issue.

I have a 08 with 4:10's and 35's. It's really not that bad. IMO get the 4:10's and if you find the power loss is really bad upgrade later.

Maverik

I have a 2012 jku rubi on order, i got the 4:10's. I have 33's to put on right now and will be getting 35's next year. The new motor has more power but the real difference is the new 5 gear auto, it is a lower ratio then the old 4 gear. 3:73's work out to about the same as the old auto with 4:10's. There are a ton of people running 4:10's/35's with the old auto and it is ok. The 3.6 has a little more umph so u should be a little better off. Put the 35's on and run it see how u like it, it won't be that bad. I am going on a tour through the states with my stock tires this summer and am actual worried the 4:10's will be to low for interstate driving, reving high and sucking gas. Also low range will be really low for most trails untill i get bigger rubber. From what i have learned 4:10's on a '12 will be like 4:56 in pre '12's and 3:73 is like 4:10 in pre '12's. What u want and like is up to u.

Mr White

iTrader: (1)

I agree and disagree on some of these responds, but to each his/her own whatever turns your wagon so to speak. I had 3.07 gears in my 03 tj with stock tires (D30 F D35 R) std., D44's looked nice but were expensive unless I was going to do some hard core offroading, so I went with gear change only to 4.11 on the same axles and a sorta limited slip on the rear. No chromium axles either. For what I do this is perfect. Was thinking of the 4.56 (cost wud have been the same) BUT if I ever wanted to go back to stock tires, I may find I'd be starting in 2-3 rd gear and the rpm's might be a little high on the hwy's. You have 3.73's new motor and put 35's you have what allot wud like to have.. Enjoy your machine and like I mentioned I wudn't go further in gearing unless it came down to hard core, and that's an all new ball game...

NathanM

Not much else i can say that wasnt said.

As far as suspension you can look at my sig and i have a couple of threads with pictures in them. Even with the "healthy 3.5" (as Rock Krawler calls it, closer 5.5" when first done) this lift kit gave me i still contact my front and rear bumpers LONG before im at full stuff. There is custom bumpers going on it to solve that problem but if you arent going to be changing out your bumpers its something to look at.
And like Ninemat said, get a nice complete kit. Dont cheap out and put a half assed kit on your nice new rig. I preach that to everybody. I have had no death wobble, tracks straight as an arrow, and rides atleast the same if not a little bit better than factory.