Shawn,
There are a few wheel manufacturer's out there that give you a choice of backspacing. Actually, to run a big tire with a narrow wheel, you should have at least 4 - 4.50" of backspacing. The 16" wheels have more than 3.50" of b/s, that's why they are recommended. I run 15X8 Welds with 4.50" b/s and I don't get any kind of rubbing. The Skyjacker 5" lift accomodates up to a 36" tire. I was going to go with 36/12.50/15 Interco TSL Radials, but I went with the MT/R's instead. The TSL's measure over 36". The 37" MT/R is acutally 36.7, so it may fit, but be pretty tight...