Dropout

Dropout is the section of the bicycle frame that contains the wheel axle. It is found at the rear and occasionally at the front of the frame. Dropouts facilitate quick wheel changes. During races, dropouts are convenient for repairing flat tires or switching bikes. Certain dropout designs can shift the rear wheel’s position, affecting the chain tension and wheel alignment. There are dropout designs that are slightly different for track bicycles, single-speed bicycles, and contemporary geared bicycles.