Shimano xt rt86 ice tec 6 bolt disc rotors for 2012 have a clad steel and alloy construction that allows heat generated from braking to radiate quickly through the aluminum core achieving surface temperature drops of around 50 deg c when used with ice tec brake pads surface temperatures can drop from around 400 to 300 deg c this provides great improvements in performance all round as for example mens mountain bikes that continue to become more diverse bike components must evolve deore xt ad