a rotor is a rotor basically, most are made of hardened steel, and brake pads are too soft to scratch them, they will all last forever xc riding unless you bash one on a rock.

larger rotors create more stopping force because of the added leverage i suppose. however rotors larger than 185 mm can have issues with standard quick releases, in other words they could rip them selves out of the drop outs.

i have noticed a difference between my standard avid rotors (roundagons?) and the clean sweaps, my standard avid rotors almost always have debris on them. the clean sweeps are alot cleaner, hence the name. the standard rotors are almost solid on the contact patch.

clean sweaps make more noise though: a subtle humming warblely sound. its hard to hear if they are adjusted right and not wet.

holes in rotors on the contact patch are mainly for shedding debris. heat isn't a huge issue unless you plan on riding the brakes for 20 minutes straight down the face of a mountain.

holes away from where the calipers contact the rotor are for saving weight, and looking cool. they do aid in cooling but i suppose its a marginal variable in the scheme of XC riding

the oldest set of rotors i have are cheapo-entry-level-shimano 160 mm. they have not warped. they are about 4 years old and. i have commuted for 4 summers to school and work. commuted one winter to work. i have close to a thousand dirt miles on that bike to and they are good as new, the contact patch of the rotors is the same thickness as the rest. basically i went through 3 sets of pads on the rear rotor and they look new.


i cant tell you whats better, centerlock or 6 hole. i prefer sixhole. however centerlocks are easy to swap between rims. i am probably going to buy a centerlock-to-six hole rotor adapter to expand my choices of brake rotors. the centerlock selection is rather limited. pretty much every company besides shimano uses sixhole