GEAR SHIFT SYSTEMS

摘要

The invention provides a derailleur gear shift system (10) for a bicycle. The system (10) includes a fluid actuated shifter mechanism (14) for shifting a drive chain laterally to select different sprockets on a derailleur gear, particularly a rear derailleur gear. The shifter mechanism (10) is connected to a control arrangement (12) by hydraulic lines (34). The invention extends to a hydraulically actuated shifter mechanism (14), and to a bicycle which includes the gear shift system (10). The shifter mechanism (14) comprises a jockey pulley which axially movable in response to turning of a tubular base member on which the jockey pulley is mounted.