Wish I could tell you for sure...but I'm in the same boat here. Currently designing my trailer on paper trying to come up with the ideal measurements for frame/box based on my tow vehicles track width and WMS(WHEEL MOUNT SURFACE) to WMS. As it stands right now, my tow vehicle and thus my trailer WMS to WMS is 60.5"...so I believe I will go with a trailer frame of 46" wide, and a 15"X8" wheel with a Backspacing of 3.75" and a 10.5" wide tire(BFG 33"x10.5"X15" ATs)...if I did all the math correctly, I should have 2.25" clearance between the tire sidewall and the box/frame. I think 2" or more clearance should be sufficient. Hopefully others can chime in on their builds.