BICYCLE DERAILLEUR AND ACTUATING SYSTEM

摘要

A bicycle derailleur gear shifting system having a rotatable handgrip actuator coupled with a derailleur shifting mechanism through a control cable system so as to control the derailleur. The derailleur (50) includes an arcuate cable entraining surface (78) which substantially reduces the variation and magnitude of the actuation ratio between control cable linear displacement and movement of the derailleur p-knuckle (88). A b-knuckle flange (160) militates against the derailment of the drive chain from the upper guide wheel while permitting maximum lateral flexing of the drive chain (48) during shifting between sprockets (46) on the freewheel. A rigid arcuate surface (174) may be provided as an extension of the b-knuckle (170) in replacement of a segment of a Bowden cable housing (38) to obviate the accumulation of water and foreign matter.