Nobody puts more thought into brake rotors than Shimano, and the SM-RT99 XTR Race Centerlock Rotor is proof of that. The hybrid steel and aluminum construction saves weight and manages heat buildup.
Even better, it's been topped off by Shimano's lightweight and user-friendly Centerlock hub/rotor interface. Now, you may be wondering what IceTech construction actually means, or then again, why it matters? Basically, IceTech rotors consist of two stainless steel braking tracks that are bonded to an aluminum inner-core.
XTR SM-RT99 Ice Tech rotors providing consistent braking performance through energy control, using revolutionary stainless steel/alloy 3-layer sandwich construction that manages heat while riding. The clad steel/alloy/steel rotor construction allows heat generated from braking to radiate quickly through the aluminium core achieving surface temperature drops of around 50 deg C. When used with Ice Tech pads surface temperatures can drop from around 400 to 300 deg C, this provides great improvements in performance all round.