Heres my situation. I have a 87 Chev shortbox with 4" BDS suspension lift, a 2 " body lift and a lot of trimming on the front and back of my front fenders. I have been running 35's on 10 bolt axles. There was lots of room and no tire rub. I am in the process of converting to a D60. a ff14bolt and new 38 by 12.5 / 15" TSL Swampers. I am not woried about calliper grinding. I can grind all day. I want to know what wheel beckspacing would be the best fit for an 8/15" rim. My local tire shop has a good on a used set with 4.5" backspacing. My concern is these rims might put my wheels too much under the truck and stuff them in to the inner fenders. (Just a note. This truck will be wheeled often on trails and rocks, not a mud truck) Any advice?