I have a 2012 jk six speed two door. Just installe 35s and a 3 inch lift and the jeep is so sluggish. It is my daily driver so I don't want to do anything crazy but what gears would be best to improve this and keep from destroying my jeep since I feel like I am grabbing gears on every hill.

 

There are tons of threads about this issue.....but here is a semi direct answer to your question

 

And if you don't have the 3.8, here is a chart for the 3.6 Pentastar

 

4.88's would be very nice on a two door with a 6 speed.

 

Great chart! I got the tire size and gear ratio, but what do the numbers in the middle mean?

 

Those are the RPM numbers your engine is at while doing 70mphs based on what size tire you have and what gearing you have. I'm guessing you have 3.21, but with the new engine you shouldn't feel it too bad. Just need to pick the right gear for the job. Obviously on hills you generally drop a gear no matter what to help the vehicle climb. We have the 3.8 with 35s/6spd/3.21 gears and it's been this way for a year now. Going to get 4.88s installed though for when we go to 37s as that'll be a good gear for highway travel, even though the RPM at 70mpg cruising is still higher than I'd like it to be.

If you plan on going 37s down the road, may as well go 4.88 gearing if you want to switch them out. If you drive on the highway a lot, maybe 4.56 or 4.10 will be better for you and save your mileage.