I had 3.21 gears with 35's , I changed to 4.56 gears. Rpm's definitely increased. I have the 5spd automatic. Jscan with an OBDII scanner is your best friend. The computer needs to k ow your exact tire size. My 35's are actually 34 inches from top to bottom. You have to measure your tires and enter that measurement into your Jscan.
