They kill discs. Used to fit them to the lambos, xbows, r26r's etc and they would eat stock, AP and perf friction discs. They also start to crumble with around 40% left. Endless pads were loads better. The lambo did the 24 hour race on one set of discs and we only changed the front pads as a precaution. Literally no wear on the discs where the pagids would do a set of pads and discs per 4 hour race.