Help with Gears
 

Looking to increase low end acceleration with stock wheels and tires. What gear ratio should I install and still be able to keep gas mileage reasonable?

Also, I am considering a slight bump in tire size to 285/70R17 so do I need to factor that into the gear equation?

last but not least. I can handle most of my mod's myself but this is way over my head so who sells 'em? who installs 'em and at what cost?

Thanks

Kinda hard to recommend something w/o knowing what you're runnin' now.

If you have 3.21's, then you could look for a set of 3.73's or 4.10's and be perfectly happy.

If you do step up a size in tires, then definitely look at the 4.10's.

If you already have 4.10's, then look at 4.88's.

Sorry about that. I'm running stock 3.21's.

Then go for the 4.10's. thats what is in the Stock Rubi's with 32" tires.. Your mileage may suffer a little though. I think the best I ever got was around 18-19mpg.

Forgot you will need 2 sets. I think they run around $500 a set. Plus installation, figure on $200 for each install. I do NOT know if you need a new carrier or not. But right there you are about $1000. AND with the 4.10's your dealer can flash your PCM so your speedo/odo work properly.

So with 4.10's I guess the stock Rubi has better (out of the hole) acceleration than the stock Unlimited X?

So you are recommending that I just take it to a Jeep Dealer to have them install the gears?

As for quicker out of the hole over the 3.21 setup. Then yes.


No, not saying taking it to the dealer thats going to be $$$$$. I am just saying that 4.10's can be programmed by the dealer. HOWEVER if the dealer IS capable of installing them, then your lifetime powertrain warranty will probably still be intact if they do the work etc..My JK didn't come with the lifetime powertrain warranty.

If you want out of the hole performance with the stock 32's the 4.10's are to tall. 1st gear is over so quickly that it's almost useless. If you look around at Rubi or 07 owners with the 4.10's this is a common complaint. I actually find that the 4.10's work better with 35's on the street since it makes 1st usable again.

This is for the 6 speed though, if you have an auto then I don't think it's an issue and the 4.10's will probably be fine.

I have an auto. Will it help that I'm eventually going to 33's or should I just ditch the 4.10's and go with 3.73's??

4.10's would be my choice for your application. As a matter of fact 4.10's are what came factory in the wifes 07 JK "X", auto with 245/75/16's. I believe it's a good combination. Although she only gets around 14 in town and 19 on the highway, her JK has good power and rides smooth both in city and highway driving. By smooth, I mean the x-mission does not do alot of downshifting when we come to minor hills.
Also, since 4.10's were a factory option back in 07, your dealer should have no problem flashing the computer to allow for proper calibration of the speedo. I would however check with them to let them know what you are intending to do, so you can feel them out.
If you are currently running the 3.21's I think you would see a nice difference once the 4.10's are installed.

Most dealers have a lot of jk's on their lots right now. Why not go and test drive a couple. Try some with the 3.73's and a rubicon w/4.10's, that may provide you an answer.