Derailleur gears by 13 drive-train. Most road bicycles have two chainrings, and touring bicycles commonly have three. The rear derailleur serves double duty: moving the chain between rear sprockets and taking up chain slack caused by moving to a smaller sprocket at the rear or a smaller chainring by the front derailleur. In order to accomplish this second task, it is positioned in the path of the bottom, slack portion of chain. Sometimes the rear-derailleurs are re-purposed as chain tensioners for single-speed bicycles that cannot adjust chain tension by a different method. Although variations exist, as noted below, most rear derailleurs have
Longest word in English likely to be encountered in general text are "deinstitutionalization" and "counterrevolutionaries", with 22 letters each. A computer study of over a million samples of normal English prose found that the longest word one is likely to encounter on an everyday basis is "uncharacteristically", at 20 letters. The word "internationalization" is abbreviated "i18n", the embedded number representing the number of letters between the first and the last. In his play "Assemblywomen" ("Ecclesiazousae"), the ancient Greek comedic playwright Aristophanes created a word of 171 letters (183 in the transliteration below), which describes a dish by stringing together its ingredients: Henry Carey's farce