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
Old English subjunctive Old English subjunctive The subjunctive mood is a flexible grammatical instrument for expressing different gradients in thought when referring to events that are not stated as fact. It is still used frequently in such languages as French, German and Spanish, and also in languages outside the Indo-European branch such as Turkish and Hungarian. In modern English only remnants of a once complex system of separate conjugations exist. What once could be expressed succinctly with the mere change of a conjugation is now only expressible, more often than not, by using word-laden modal constructions. The word subjunctive as used to denote