i was wandering if anyone can help me at all. I was going to change my discs today and after removing the caliper the two bolts at the back which hold the pad holder and the caliper have a special sort of head on which is a star shape. I stuck a 13mm socket on it and all it did was start to round the head :/. does anybody know how to get this bolt off and what special tool is needed? can get pictures if needed!

They are Ribe from memory

thanks mate. i did a bit more research and some are saying torx or torx plus. i actually had no idea there was torx sockets, on drivers. whats the difference between torx and ribe?