I got tired of the squealing from the rotors that came with my latest bike (mtb) so I bought some el-cheapo rotors for $3.bucks a piece and they not only don't squeal like a stuck pig, they stop a whole lot better than the stock rotors ever did. 6 bolt 160mm is fairly common and cheap. BTW-rotors flex a lot under use and it takes a lot to over heat them despite what others will tell you. There are also different rotors for different uses. Some will stop you so hard you go over the handle bars (rock hoppers) and some are much more smooth. HTH