i run 325.60.20 toyo A/T on moto metal wheels, with a 6 inch procomp lift what other size tires can i run with the back spacing of my rim. idk what the back spacing is how can i find out what back spacing it is

 

Thats as big and wide as you can go with that lift, those are 35's, I doubt 37's would fit because my buddy has that lift and that set-up, not sure the backspacing on his rims, Im pretty sure it 4.5 and he has some minor rubbing. You could pretty much only go shorter and less wide. Also, not sure how to tell backspacing on rims.

 

Backspacing: