Abstract: A derailleur 10, for moving a chain 60 to different sized sprockets arranged small to large in a sprocket nest 101 is disclosed. The derailleur 10 has a pivot guide feed arm 11 for directing the chain 60 onto one of multiple sprockets within the sprocket nest 101. The pivot guide feed arm 11 is rotatably mounted at a pivot end on an angular pivot pin 12 and when the pivot guide feed arm 11 rotates about the pivot pin 12 an opposite chain guide end of the pivot guide feed arm 11 traces a path substantially parallel to a tangent to the outer periphery of the sprocket nest 101. The movement of the pivot guide feed arm 11 is mechanically driven by a user command and is preferably moved by a connected rod or wire or cable 109.

Abstract: A derailleur 10, for moving a chain 60 to different sized sprockets arranged small to large in a sprocket nest 101 is disclosed. The derailleur 10 has a feed arm for directing the chain 60 onto one of multiple sprockets within the sprocket nest 101. The feed arm 11 is rotatably mounted at a pivot end on an angular pivot 12 and when the feed arm 11 rotates about the pivot 12 an opposite chain guide end of the feed arm 11 traces a path substantially parallel to a tangent to the outer periphery of the sprocket nest 101. The movement of the feed arm 11 is mechanically driven by a user command and is preferably moved by a connected rod or wire or cable 109. The guide end of the derailleur 10 has a chain guide, wherein the chain guide is a smooth surface or a roller or toothed roller. The derailleur 10 further has a chain slack take-up assembly having a pivotal take-up idler arm 20 for chain slack take-up, which is pivotably connected to the chain guide end of the feed arm 11.