derailleur

剑桥词典

a type of bicycle gear that works by moving the bicycle chain from one sprocket wheel (= a wheel with a row of tooth-like parts ) to another
（自行车的）换挡装置，变速器
Set the rear derailleur in the lowest gear , with the chain on the biggest sprocket wheel at the back. 把后轮的变速器调到最低挡，就是让链条在后面连到最大的链齿上。
derailleur gears 换挡齿轮 返回 derailleur