Yeah ... I just inspected my rims. They're not more than a few weeks old. The sandpaper sound is from the rims(Mavic A719) being coarse. After cleaning them, I noticed tiny bits of metal embedded on them. My previous pads were Aztecs, which I used for about a week....and sure enough there were bits of metal in them. What crap. I've use the same rims for 11 years on another bike and I never had this . The Tektro pads just added to it. Gotta get some new pads fast. I'll probably swap out the brakes with some non offending pads until I do.