Patent ID: 7380646

Claim:
A master cylinder assembly for a hydraulic bicycle braking system comprising: a master cylinder having a first end and a second end; a first piston disposed in and movable within the master cylinder, wherein the first piston has a first end, a second end and an axially aligned through hole; a second piston disposed in and movable within the master cylinder, wherein the second piston includes a larger diameter portion and a smaller diameter portion having a distal end that extends through the hole in the first piston; a first fluid containing region at least partially defined by the second end of the first piston, the distal end of the smaller diameter portion of the second piston and the second end of the master cylinder, wherein the first fluid containing region includes an outlet that extends outside of the master cylinder, and wherein a first pressure is applied to the second end of the first piston by the fluid in the first fluid containing region; and a modulator configured to modulate the first pressure.