Tell me about it, LOL. I currently run 15x8 rims with 3.75" backspacing. Every chance those suckers get they grab at the rear of my front fender (yay, more sawsall). But then again im running 33's. From what I understand and have seen you can run up to 31's with 4" backspacing without needing to trim. Anything beyond those and you need to start hacking the fenders.

 

so what exactly is offset? i have seen that pic that swartlkk posted about all the different measurements of a wheel but im not really sure why you need to know the offset if you know the backspacing

 

From what i understood offset was the same as backspacing. At least thats how ive always heard it referred to as. Tim, Kyle, you guys know for sure on this?

 

Yea offset and back space is the same thing. Your safe betis to get no less than a 4.5" back space unless you dont mind cutting your truck up. Go to www.synergyoffroad.com, they sell alot of stuff for our trucks especially wheels.