Derailleur gears
Derailleur gears are a gear system commonly used on bicycles. They consist of a parallelogram device called a "mech" which is operated by a cable. When the rider decides to change gear, the mech is moved from side to side by the changes in cable tension, and as it does so it "derails" the chain onto different gears. The front derailleur and rear derailleur differ in appearance and function, mainly because the front derailleur moves the chain a shorter distance and that the rear derailleur is also responsible for maintaining chain tension.Various derailleur systems were designed and built in the late 1800s. The French bicycle tourist, writer and cycling promoter Paul de Vivie, aka Velocio, (1853-1930) invented a two speed derailleur in 1905 which he used on extensive forays into the Alps. Some early designs used a system of rods to move the chain onto various gears. Derailleurs did not become common road racing equipment until 1938 when Simplex introduced their cable shifted derailleur. In the early 1950s the cable-operated, parallelogram variety used on today's bicycles was introduced by Tullio Campagnolo, who also invented the quick release skewer for attaching the wheels. With Campagnolo's introduction of the parallelogram front derailleur, Campagnolo became the standard for high quality derailleurs and for several decades true racing bicycles were all campy, meaning that the derailleurs, shifters, hub and chain were all manufactured by the Campagnolo company. The major innovations since then have been the gradual increase in the number of gears on both hubs (on racing bicycles, 11-gear rear hubs are appearing as of 2003, and most current bicycles have at least three front gears), and tensioning systems designed for one-push gear changes. Derailleur gears are the most common type of gears used on bicycles today.
The alternative type of gear system used on bicycles are Hub gears.
Fixed gear cyclists eschew the use of derailleurs favoring a simpler, more rugged configuration with fewer, or zero, cables. They enjoy quoting Henri Desgrange, the founder of the Tour de France:
- "I still feel that varable gears are only for people over forty-five. Isn't it better to triumph by the strength of your muscles than by the artifice of a derailer? We are getting soft...As for me, give me a fixed gear!" (L'Équipe article of 1902)
