Abstract: The pre-timed distribution unit, in particular for internal combustion engines, is constituted by a first sprocket wheel, and a second sprocket wheel with a plurality of sprocket sets, a multiple-link chain taut between said sprocket wheels and defining a space inside which a guide shoe is housed, which is constituted by at least a plate-shaped structure provided with guides radiused by a first and a second mating, trueing circumferential edges. In an alternative form of practical embodiment, the unit comprises a guide shoe whose guides are associated with enlarged, laterally protruding portions.

Abstract: A bicycle wheel brake consisting of a pair of opposed friction blocks carried by respective levers pivoted, either directly or through a support, to the bicycle frame, so as to be controllable against the action of spring members to lock the blocks against the wheel rim. Each lever is pivoted at one side of the wheel so as to move on a plane substantially parallel to the plane tangential to the wheel.

Abstract: A motor unit for bicycles, characterized by the fact that it comprises a central axle for fitting to the fork of a bicycle, on which axle is rotatably supported a substantially cylindrical body adapted to form the hub of a wheel, there being fitted within said body and to the central axle the stator of a discoid rotor electric motor connected to the body by a kinematic transmission.