Derailleur gears operates the lever while pedalling, the change in cable tension moves the chain-guide from side to side, "derailing" the chain onto different sprockets. For more information about the choice of particular gear ratios and sprocket sizes, see Bicycle gearing. "Derailleur" is a French word, spelled "dérailleur" in French, derived from the derailment of a train from its tracks. Its first recorded use was 1930. At least one notable bicycle industry author has attempted to promote the anglicized spelling of "derailer". As of 2013, however, neither Merriam-Webster nor the Oxford English Dictionary has an entry for "derailer". Various derailleur systems were
Glossary of French expressions in English in the original language, to the extent that they would not be understood (either at all, or in the intended sense) by a native French speaker. c'est la guerre: "That's war!", or... c'est la vie: "That's life!" or "Such is life!" Through the evolution of the language, many words and phrases are no longer used in modern French. Also there are expressions that, even though grammatically correct, do not have the same meaning in French as the English words derived from them. Some older word usages still appear in Quebec French. International authorities have adopted a number of words and