With the release of the XT M8100 series 12-speed mountain bike groupset, the Japanese component giant delivered the MT800 disc brake rotors, which in most ways resemble the XTR grade MT900 versions. You get the evolving Ice Technologies stainless steel-aluminum, stainless steel sandwich construction, as well as the extended aluminum layer, which spreads outward into the IceTech FREEZA Radiator design. Most of what you miss out on as you save cash over XTR is the painted surface of XTR's Radiator, which further increases cooling. Not that the MT800 is slouch in the heat management department. IceTech and Shimano have proven the effectiveness of the sandwich construction and FREEZA over the two previous generations (mountain and road) and the refinement keeps delivering real world improvement.

Designed for the rigors of mountain bike trail use with both 2 and 4 piston caliper brakes, the MT800 are durable and deliver sure power and control while defying fade. These rotors are also pretty darn light, and feature a machined aluminum spider with a spoke design that pins to all three layers of the sandwich for increased stiffness. In the 140 and 160mm versions, a 4-spoke system gets the job done, while the larger options reflect the greater diameter and brake load requirements. Why a 140mm option for trail use? Well, a few XC racers might prefer that, but it is more likely that Shimano was considering the crossover appeal with gravel and user groups. Capable of handling the surfaces of both resin and metallic brake pad compounds, the MT800 can suit just about any rider, and the new design is considered to be exceptionally quiet with the resin compound, while metallic is still the best choice for seriously gritty and wet conditions.

The XT RT-MT800 Disc Brake Rotor is available in 160, 180, and 203 mm sizes, and this is the Center Lock version. An External Serration alloy Center Lock compression lockring for 15mm thru-axle uses is included for this impeccably simple and wholly effective mounting set-up. The MT800's can be trued with proper tools and some patience, but be sure to work off the steel surfaces and not the Radiator fin. For best overall brake system heat management results, Shimano and IceTech recommend their finned disc brake pads, though the non-finned versions are fully compatible.