What Gears?

[ChiliPepperGarage]

My brother in law has a 2012 JK and is running 35's on stock gears (Dana 30/44). He wants to get lockers and re-gear but thinks he may want to run 37's at some point. Currently has a LSD in the 44 and open in the 30. He was going to go to a new 44 for the front but decided to stick with the 30 for now.

My advise was to wait a while (he's had it a year and has only been wheeling twice) and see how he is going to use it. Maybe just put a locker in the front for now. He doesn't want to wait and ordered Eton lockers for both axles but is now thinking about gears. We think the current stock ratio is 3.24(?) and he thinks he should go to 4.56 of 4.88's. I think those are way too steep as it's not too bad with the stock gear. I had a ZJ with 33' and 4.56s and it was pretty steep so I drove it around town but trailered it to the trails.

An other thing is I don't think he will go to 37's and if he does the 30 isn't going to last anyway.

Anyone with a JK and 35/37's? What gear are you running?

 

[Cole Trickle]

My brother in law has a 2012 JK and is running 35's on stock gears (Dana 30/44). He wants to get lockers and re-gear but thinks he may want to run 37's at some point. Currently has a LSD in the 44 and open in the 30. He was going to go to a new 44 for the front but decided to stick with the 30 for now.

My advise was to wait a while (he's had it a year and has only been wheeling twice) and see how he is going to use it. Maybe just put a locker in the front for now. He doesn't want to wait and ordered Eton lockers for both axles but is now thinking about gears. We think the current stock ratio is 3.24(?) and he thinks he should go to 4.56 of 4.88's. I think those are way too steep as it's not too bad with the stock gear. I had a ZJ with 33' and 4.56s and it was pretty steep so I drove it around town but trailered it to the trails.

An other thing is I don't think he will go to 37's and if he does the 30 isn't going to last anyway.

Anyone with a JK and 35/37's? What gear are you running?

I have factory 4:10 on 35 and I think its about perfect on and off road.

With a 44 rear there is a good chance he could have 3:73 if its an auto.

Personally I think building up that 30 is a huge waste of $$$ as he is going to have issues with 35+ tires if he wheels it.

Gear wise I would prob go 4:56 with 35's and 4:88 with 37's.

 

[Rivertoys]

The 2012 has 80 more HP than the 07-11, and therefore doesn't need as much gear, so people are reporting. My '09 manual tranny is on 4:10s with 315/70s (just under 35"). I was dead set on re-gearing and EVERYONE (Jeep forums, Mel at ORE, as well as some shops back east that I was talking to) said that I should go 4:88. I really think that's too much for what I do. Other having lost most use of 6th gear, I don't have a big issue with the 4:10s. I can run well on the frwy, and living in coastal OC, I need a lot of frwy to get to the trails. I don't do extreme off-roading, or rock climbing, I explore. I still plan to re-gear and though I might end up with 4:88, I am leaning towards going against all advice and getting 4:56.... knowing my truck and what I do. My JK is also very light as Jks go, 2dr, soft-top.

My answer to your question.....for the '12, I think 4:56 will be plenty. I think 37s will stretch that D30 to the extreme. My opinion, you'd be better off saving for a complete axle upgrade.

Tons of people wheel D30s all day long without trouble....but you have to know the limits and know what you're doing. My D30 is sleeved, and has gasseted Cs. I do all the work myself, so it wasn't a large $ investment at all. It's the least I would do before wheeling 35s on that axle. I did a lot of homework, my Goodyear 315/70s weigh 17lbs/each more than the stock 32" MTs. I tried to all as little weight as possible. Just little things to consider....

Good Luck!!!

 

[Deleted Account]

37's kill everything on a D30. I told you so...