BR-M9100 
 2-piston caliper of hydraulic disc brake 
 
Higher braking force with less fingertip effort, providing high linear response, braking power, stroke, 30% reduced range compared to M9000
New high rigidity brake tube and one-piece aluminum caliper
26g lighter (vs. BL / BR-M9000 with disc brake rotor)
High performance braking control
High rigidity
Light
Linear pipe union
 
 Hydraulic Disc Brake Lever 
 
Faster resumption between operations keeps rider focused
More flexible configuration cockpit for easier operation
Reshaped brake lever
Stiffness increased by 10% over M9000 even at high temperatures
Magnesium Master Cylinder
26g lighter (vs. BL / BR-M9000 with disc brake rotor)
Integrated operation
High rigidity
Light
Faster brake brake with shorter free stroke