Abstract: A self-energizing brake which includes opposed rocker arms attached to a frame by a bolt or the like. The rocker arms also include a housing extending transversely therefrom which is rotatable about the bolt. The housing encloses a tubular member having a plurality of helical ridges which mate with a plurality of bearings disposed about the inner surface of the housing. The housing is axially movable relative to the bolt. The housing is sealed about the bolt by O-rings and contains a lubricant such as grease. Friction pads extend from each rocker arm adjacent the rim of a tire to contact the rotating rim as the rocker arms are related. Such rotation results in movement of the housing in an axial direction as the rim drags the friction pads forward.