totdoc

Going to be completing my 2012 build very soon - I will be running 37 MTRKs on my 2012 manual JKU, and I am having a really hard time deciding between 4.88 and 5.13 gears.

I live in Florida (read - flat, sealevel elevation), use the Jeep as my DD, and I do spend a bit of time on the highway. Gas mileage is still somewhat important to me

I know that 5.13's were pretty much the standard for manuals on 37's in prior year Jeeps, but I am wondering if this has changed at all with the new engine? Is anyone running 37's on 4.88's with their 2012 manual? I'd love to hear your thoughts!

Merlin4979

I'd stick with the 4.88's. You have the new motor, you have the manual tranny, you live in a flat area, and most importantly - you do a lot of highway driving. That will let you still get to those higher speeds without red-lining it.

2BAJeep

I have a 2012 2dr Rubi running 4.10 with 35s and I love it. I even drove it in the mountains of NC with no issue. I would bet the 4.88s would be plenty for 37s.

BrettDez

I agree. Mine's a 2012, 4-Dr Rubi, 4.10s, 35s, 6-spd manual, and a snorkel. I have no problems with the new engine. I might regear to 4.88 just to get even more oomph but it's not needed for sure.

I think 4.88s and 37s will be just fine.

totdoc

Thanks everybody. I think 4.88's sound like a winner. I actually talked to someone who had an '07 with 37's and 5.13s, who now has a '12 with 4.88's and 37's - says it works great, and their highway gas mileage isn't too shabby, either!