I have a 2010 basic sport two door. I threw away the spec sheet that was on the window when I bought it and now Im wondering what gearing I have since I want to upgrade my tires to 35's. I am currently running bighorn maxxis 265/ 75/ 16's up from the stock 29 inch tires with no problems, but now with the BB, HD coils and chopped fenders the tires look a little small.

Ive looked at the gearing chart and if I have the 3.21 gears it doesnt look good at all for 35's, if i have the 3.73 gears it looks like it will most likely be bearable for awhile until I can afford to upgrade....

Any thoughts or ideas?

Thanks!

 

Best bet is to give your VIN to a dealer and they can look that up for you in a snap.

If you are a secondhand owner, then you need to jack up the jeep and count how many times the driveshaft spins. I am not sure on the numbers, but people will chime in.

And I have been talking with people with 3.21s and a manual and they say 35s are not too bad for a while. I plan on going to 35s with my 3.21s for a bit.

3.21's on a 6 speed is slightly better than 4.10s on an auto according to the gearing chart in the FAQs. You should be fine for city driving, but highway might be a pain. If you have a 6 speed, just drop it to 5th or 4th and you can deal with it.

 

Jack up the rear end, rotate tires and count the driveshaft rotation. quicker than driving to the dealership, ~ 5 minutes.

 

Try the VIN decoder in the Research area here:
hxxp://www.compnine.com/index.php

If your jk is in the system, it will show your build sheet.

 

Do you have a towing package and a 44 rear axel? If so you're most likely running 4.10s – another quick way is to use this chart.