About 6 months ago I put some 15" steel wheels from Discount Tire on my 2002 R50. They barely cleared the caliper and I had no problems with them, until today. I just finished installing new wheel bearings and replaced the rotors and pads while I had it all apart. When I first installed the 15" wheels my brake pads were pretty worn, now that the new pads are on the caliper rubs the wheel. Lol I thought for sure I had installed the bearings wrong, because the noise was terrible! The new, thicker pads, set the caliper out further causing them to touch the wheels. I ended up grinding a little bit off the caliper and everything seems fine.
So if you are test fitting a wheel, make sure your brake pads are relatively new!