Dictionary

derailleur en · NOUN

Pronunciation

• /dɪˈɹeɪl(j)ə/ (Received-Pronunciation)
• /dəˈɹeɪləɹ/ (General-American)
• (Southern-England) audio

Etymology

Unadapted borrowing from French dérailleur, from dérailler (“to derail”) + -eur (suffix forming masculine agent nouns from verbs). Dérailler is derived from dé- (prefix meaning ‘away; from; off’) + rail (“rail”) (ultimately from Proto-Indo-European *h₃reǵ- (“to righten; to straighten”)) + -er (suffix forming infinitives of first-conjugation verbs). Doublet of derailer.

Meanings

1. A mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket (gear) to another, to change speeds.
   • The common rear derailleur designs all operate on the same principle. A moveable cage receives the chain returning from the chainwheel and directs it onto one sprocket of the cluster. Moving the cage sideways directs the chain onto a different sprocket. 1984, John Forester, “Derailleur Adjustment”, in Effective Cycling, Cambridge, Mass.: MIT Press, published 1985, →ISBN, part II (Bicycle Maintenance), page 79:
   • Very few bicycles are of a different color or employ more gears with derailer sprockets and hand brakes. […] In short, most adult commuter bicycles are almost interchangeable; and therein lies the tale. […] At first glance, one wonders how commuters can identify their own machine from the pack of identical black bicycles, particularly if they are in the center of the pack. The answer is, they don't! They simply grab one that is convenient, ride it home, and then return it to the pack the next day. 2009, Louis G. Perez, “Society in the Twenty-first Century”, in Frank W. Thackeray, John E. Findling, editors, The History of Japan (The Greenwood Histories of the Modern Nations), 2nd edition, Westport, Conn.; London: Greenwood Press, →ISBN, →ISSN, page 202:
   • [H. A. G.] Keates again rode a fully-equipped machine (lamp excepted) and used a derailleur gear. It was probably this variation which enabled him to progress so well against the wind and yet take full advantage of its assistance on the return trip. 1934 December 3, “Cycling club disbanded: Shamshuipo club to be formed: Brief review of activities: Keates sets new record”, in The China Mail, final edition, number 28,898, Hong Kong: The Newspaper Enterprise, →OCLC, page 9, column 1:
   • A bent [derailleur] hanger will torpedo your shifting, and possibly even throw your rear derailleur into the spokes, so straightening derailleur hangers becomes a very common repair. […] Plug your Allen wrench’s short end into the derailleur’s mounting bolt, then grasp its long end with one hand and the derailleur body with the other, moving both simultaneously. 2024, Sam Tracy, “Frames”, in Riding More with Less: A Future for Bike Repair, Oakland, Calif.: PM Press, →ISBN, page 11:
   • By flicking the gear lever, you can flip the chain onto different pairs of gear wheels so, effectively, you're changing the relative size of the two gear wheels connected together. A cunning mechanical gear-shift called a dérailleur allows you to do this as you’re bicycling along, even while the gear wheels and the chain are spinning at speed. […] In a high gear, for racing down the straight, the back wheel will turn more quickly than the wheel you pedal (faster and with less force). In low great it's the opposite, with the back wheel turning more slowly but with a huge dollop of extra force for digging in and crawling up hills. 2015, Chris Woodford, “The Beauty of Bikes”, in Atoms Under the Floorboards: The Surprising Science Hidden in Your Home, London; New York, N.Y.: Bloomsbury Sigma, Bloomsbury Publishing, →ISBN, page 67:
   • The chain is guided by dérailleurs from one sprocket to another, front and rear, until the gear ratio desired is reached. […] Generally the problems in this area will be with the dérailleurs or the chain. Still, it is possible that a bad chain will have worn the teeth on the freewheel or the front sprocket. 1973, Ross R[obert] Olney, “Chains, Sprockets, and Pedals”, in Simple Bicycle Repair and Maintenance, Garden City, N.Y.: Doubleday & Company, →ISBN, page 28:
2. The entire gearset on a bicycle with such a mechanism.

Forms

Deriveds

derailleur hanger

Translations (31)

vi sang đĩa (mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket to another, to change speeds) · ru переключа́тель (mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket to another, to change speeds) · sh mjenjač (mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket to another, to change speeds) · sh menjač (entire gearset on a bicycle with such a mechanism) · fi vaihteet (entire gearset on a bicycle with such a mechanism) · de Schaltwerk (mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket to another, to change speeds) · sh menjač (mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket to another, to change speeds) · it deragliatore (mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket to another, to change speeds) · sh mjenjač (entire gearset on a bicycle with such a mechanism) · pt desviador (mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket to another, to change speeds) · cs přehazovačka (mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket to another, to change speeds) · ga aistreoir slabhra (mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket to another, to change speeds) · pl przerzutka (mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket to another, to change speeds) · nrf dêrâlleux (mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket to another, to change speeds) · es descarrilador (mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket to another, to change speeds) · ca desviador (mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket to another, to change speeds) · pl przerzutki (entire gearset on a bicycle with such a mechanism) · cs přesmykač (mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket to another, to change speeds) · fi takavaihtaja (mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket to another, to change speeds) · fi etuvaihtaja (mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket to another, to change speeds) · pt descarrilador (mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket to another, to change speeds) · sv växelförare (mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket to another, to change speeds) · sv kedjeväxel (entire gearset on a bicycle with such a mechanism) · fi vaihtaja (mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket to another, to change speeds) · es desviador (mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket to another, to change speeds) · de Umwerfer (mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket to another, to change speeds) · es cambio de marchas (mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket to another, to change speeds) · nl derailleur (mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket to another, to change speeds) · cmn 變速器 /变速器 (mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket to another, to change speeds) · fr dérailleur (mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket to another, to change speeds) · sv kransväxel (entire gearset on a bicycle with such a mechanism)