Motorcycle disk brake is widely used because of its small radial dimensions, axial application of force along the disk when braking, no bending moment on brakeshaft and braking stability.
In his application Selden described a machine with a gasoline-driven, combustion-type engine that sat in front of the driver; a clutch; a foot brake; a drive shaft; and front-wheel drive.
申请中，赛尔登描述了一项机器是石油驱动、在驾驶座前有燃烧式发动机；离合器、脚刹车、前轮驱动。
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The shaft must test in bearings, may be started by a clutch or stopped with a brake.