Iv got an '07 X and Im looking to upgrade from 33" tires to 35" or 37"s but im not sure how the gearing will be effected. Im not very familiar with gear ratios and how everything compares to tire size, power, gas mileage etc. Any help would be great!

Also, I was thinking of maybe doing a whole axle swap to Rubi 44's. Anyone have suggestions on that? Where would I find a used set of Rubi Axels? If I were to do that, would I need to re-gear for 35" or 37"'s anyways?

 

Check out the FAQs thread, there is a plethora of information on gearing and lifting and everything in between. Most will advise going with the lowest gearing possible especially with an auto. Having the rubi D44s opens up another step from 5.13s to 5.38s.

Do a search on regearing a JK and you will have enough to read for the rest of the week

 

If you've got an automatic, with the front D30 in the X, the highest you can go is 5.13 - which is in the GREEN zone for an automatic on 35's. (true 35"... not 35's that only measure 34")

35's on a 6-speed, you can chintz out at 4.10, or 4.56 for 37's.
Check the table here:
https://www.jk-forum.com/forums/show...l=1#post211276

 

Thanks, that helps a ton!