I currently have stock rims on my jku with 33 inch tires. I would like a wider stance. If I get rims with a less backspace. Would I need to buy new tires or would the set I have fit?

 

not likely. If you go with a 9" wide rim, you can fit just about width tire from 10.5 to 11" wide upto a 13" wide tire without stretching or bulging the tire to the point where it looks dumb.

You should check the tire you have for the recommended wheel width. They usually provide a range on the manufacturers website. And you can usually add your own tolerance to that, +/- 1/2 to one inch and still be in a safe zone.

 

The less backspace you have the further it will stick out. I believe stock BS is 6.25