I have an 07 jk 2dr auto 3.21 gears and bare stock 29" tires. I wanted to go to 35"s, but I can't afford new wheels tires and gears at the moment. The other day I came across a ratio chart that said for the 3.21 auto I would have to regear for any size above 29". If i get 33"s do I really risk breaking anything. Does anyone have this setup, if so...is there huge power loss/decrease in mpg's?

 

I ran that set up for 60K miles. Wish i would have regeared a long time ago. That being said, it's doable, so just get the tires, and regear when you have the bucks. If you have a manual that is... i don't know about automatics. btw, 6th gear will be totally useless.

 

I run 32/11.5R15 i have 3.21 and six speed i have zero problems i plan on going up to 35s just get a tuner

 

You could still run 35s if you wanted to. If you have an auto just turn off the overdrive. I did that for a year and it really was not that big of a hassle. Save up the money and then regear once you have it.

 

You ran 35"s with 3:21 auto? What were your mpg's like and how bad was the power loss?

 

3.73 Auto - I don't really remember my MPG. I want to say I was in the 16s in the city. I always ran with overdrive off so I did not really notice a power loss. It was not bad at all. I do mostly city driving so I'm not sure how it would be on the highway.

I did this pre-supercharger for about a year. I did have a superchips tune, CAI, and MBRP cat-back.

I was only saying you could run with th overdrive off to help if you wanted to still go with the 35s until you had the money for the gears. It would help. Helps keep you above 2000rpms all the time.

 

You can definitely run 33s on 3.21 auto and 3.8L. The key is to use lower gear. That's basically what regearing does.

 

Just so you know... When you go up in tire size on an auto it messes with the computer and you don't get the proper shift points. In other words it will just drive shitty. Make sure you recalibrate the computer for bigger tires. And dealer can do it or you can buy one.