Originally Posted by phillip@bmpdesign
May be quicker and more accurate to measure yourself. General rule of thumb is measure the gap between the shoulder of your tire and the inner fender well, then back it off about 1/4" for clearance. You can do 1/8" if you accept that you may have to roll your fenders.
Off the top of my head for that spec wheel: 12mm is a pretty safe bet, 15mm may be pushing it, 20mm would probably require rolling the fenders.
Thank you for your input. I will go for the 12mm spacers in the rear.