Abstract: An index shifter for a bicycle transmission, which index shifter is mounted on a part of a bicycle and has a casing, a locking element with notches which is connected to a rotary hand grip, and a winding drum for actuating a cable pull. The casing has a ring-shaped recess disposed therein, in which recess a detent spring is arranged. The detent spring is braced by two feet against the casing and has a lug which engages with the locking ring. Inside the casing is a casing projection with which one foot of the detent spring can be fixed to achieve a small amount of shift play. This permits small amounts of shift play, in particular for shifting hub gears on bicycles.

Abstract: According to an illustrative example of the invention a transmission lever for transmitting an actuating force from a pull cable to a push rod of a bicycle hub gear change mechanism is pivotally mounted on a housing. The housing is provided with a sleeve which sleeve is rotatable and axially fixed with respect to the housing. The sleeve is provided with an internal thread for engagement with an external thread of a hub axle. For assembling the housing with the hub axle the sleeve can be locked against rotation with respect to the housing.

Abstract: The invention relates to a gear-change device for derailleurs or gear-change hubs in which by enlargement of at least one of the provided detents in the circumferential direction and by arrangement of a spring which biases the change lever in the one direction an easy adjustability is provided by an adjusting screw. Furthermore the exchanging of detent discs for easy adaptation to different gear ratio numbers is easily possible. The assembly of the gear changer is easy to effect in as much as two component groups can be prefitted independently of one another. A shift-over device for one direction, as utilized advantageously especially in derailleurs, can easily be integrated.

Abstract: A derailler system for a bicycle including a sprocket system having a plurality of drive sprockets and a chain for driving a wheel of the bicycle at different speeds with the chain being shifted onto individual drive sprockets by movement of an idler sprocket. A movable carrier member has the idler sprocket rotatably mounted thereon for selectively shifting the chain and a guide system is provided for guiding movement of the carrier member along the path essentially parallel with the axis of the driven wheel. A shifting mechanism for actuating the guide system includes a shift lever enabling shifting of the movable carrier to a plurality of shifting positions corresponding with the drive sprockets and a cam follower member including a cam follower rotatably mounted on a first part of the guide system is arranged to engage a cam member mounted on a second part of the guide system which is movable relative to the first part.

Abstract: A bicycle having a rear derailleur arrangement for its drive chain which includes a four-bar linkage consisting of a support, two links, and a coupler, first and second pivots securing the support to the links, and third and fourth pivots securing the coupler to respective links. The support is fixedly fastened to the rear wheel shaft whose axis is parallel to a plane which is perpendicular to the parallel axes of the pivots and defines an angle of 15.degree.-45.degree. with the vertical in the normal operating position of the bicycle. A guide sprocket for the chain is secured to the coupler for rotation in a plane perpendicular to the shaft axis. All four pivots are offset from the shaft in a downward direction, and the first and second pivots are farther from the shaft than the third and fourth pivots.