Olaf- something to watch out for. I am having problems with mud getting on the inside of my rims, then gravel and small rocks will stick in the mud. The rear calipers don't have enoungh clearence so the rocks will get stuck between the rim and the rear caliber and mill a nice groove in your rim. I have three rims with some nicely milled grooves now. I just hope that one rock doesn't wear a rim al the way through.