Derailleur gears

Derailleur gears are a type of gear system commonly used on Bicycles. Which consists of a device called a "Mech" which is operated by a cable and 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.

Derailleur gears were invented by French inventor Paul de Vivie[?] (1853-1930) in 1905. Some early designs used a system of rods to move the chain onto various gears. It was not, however, until the early 1950's that the cable-operated variety used on today's bicycles was introduced 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.

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