Derailleur gears Derailleur gears Derailleur gears are a variable-ratio transmission system commonly used on bicycles, consisting of a chain, multiple sprockets of different sizes, and a mechanism to move the chain from one sprocket to another. Although referred to as "gears" in the bike world, these bicycle "gears" are technically "sprockets" since they drive or are driven by a chain, and are not driven by one another. Modern front and rear derailleurs typically consist of a moveable chain-guide that is operated remotely by a Bowden cable attached to a shifter mounted on the down tube, handlebar stem, or handlebar. When a rider
Derailleur gears = 45T; medium = 33T SRAM long = 43T; medium = 37T; short = 30T Benefits of a shorter cage length: There are at least two methods employed by rear derailleurs to maintain the appropriate gap between the upper jockey wheel and the rear sprockets as the derailleur moves between the large sprockets and the small sprockets. The actuation ratio is the ratio between the amount of shifter cable length and the amount of transverse derailleur travel that it generates. Shift ratio is the reciprocal of actuation ratio and is more easily expressed for derailleurs than actuation. There are currently