i am new to the jeep world and i bought this xj with these rims already on how do i determine the back spacing. i would like to put bigger tires on it. it has 235 70 15s on it now and i have 5 ins between tire and flare i have been reading a lot of posts it sound like i will have to go with 3os till i get lift is that correct.i also have read a lot about sye's if i go with a 3in lift that is would be not needed correct?

 

Here's a pic of what BS is and another on how to measure it. What you're concerned with is the "rear spacing" towards the bottom of the top picture.

My guess is you have anywhere between 3.75" and 4.5" of BS which would be just fine for 30's.

 

thanks for the help next week tires. this spring lift and bigger tires