I hope it doesn't mean "for disk brakes ONLY". The rim has this hard anodized coating and is so super slick on the braking surface that the pads seem to vibrate and cause squeal. So far I tried all different setting and get the best results with the Shimano XTR Extreme Condition pads set flat to the rims (no toe). Still squeals but not as much, only when the pads are cool do they squeal a lot. Will try the ceramic-specific pads when they arrive.