The selector (S) for the derailler gears of a bicycle is mounted under a conventional derailler (D) having a parallelogram mechanism. The parallelogram mechanism moves a chain (5) guide support (6) equipped with rollers to take up varying lengths of chain according to the size of gear used. The position of the mechanism is remotely controlled via a cable (11) by a lever which is brought to a central position by a return spring. The exact position of the parallelogram is controlled by a notched plate (c) moving against a locking tooth. The notches are arranged to hold the parallelogram in one of the positions corresponding to a selected gear. The gear may be changed up or down by moving the lever in one of the two directions from the central position against the spring force. Provision is made to adjust the positions at which the notched plate holds the chain guide.
展开▼
