A fluid cylinder assembly for a hydraulic actuation system for a bicycle is provided. The fluid cylinder assembly includes a fluid cylinder. The fluid cylinder includes a housing and a piston that is movable within the housing. The fluid cylinder assembly also includes a force applicator connected to the piston of the fluid cylinder, a support, and an actuator pivotably attached to the support. The actuator is operatively connected to the piston of the fluid cylinder via the force applicator, such that the actuator is configured to translate the piston from a first position to a second position when the actuator is actuated. The fluid cylinder is attachable to a handlebar of the bicycle, such that part of the fluid cylinder is positioned within the handlebar and at least part of the force applicator is radially outer relative to the handlebar.