Shimano's XTR M9100 series brings it all back to mountain bike racing components. With 27 years of operation under their belt, Shimano knows that trail conditions change rapidly from one turn to the next and that racing means needing reliably precise components. Their XTR BR-M9110 Flat Mount Brake Caliper reflects that and offers a clean design that's compact but mighty. It delivers performance in all conditions, and it has the same braking power as a post-mount 2-piston caliper brake. We're into the fact that this brake delivers reliable stopping power without a hitch, and that it is compact enough to maintain a lightweight 341g. It has the same frame requirement as a road flat-mount brake, and it is compatible with 140 and 160mm disc brake rotor sizes.