Abstract: A bicycle dynamo for a bicycle having a frame and a wheel has a stator, an internal stationary winding fixed on the stator, and an external rotor rotatable on the stator. This rotor has a rotatable cylindrical external casing surrounding the winding and formed with an outwardly open annular groove, a plurality of permanent magnets inside the casing that generate an electrical voltage in the internal stationary stator winding, and an elastic ring frictionally engageable with a rim of the bicycle wheel, set in the annular groove, and projecting from the outer casing. A holder carries the stator.

Abstract: The invention relates to an electric drive for bicycles, comprising two symmetrically arranged external-rotor type counter-rotating motors which are fed via two separate motor actuators/regulators that obtain the same control signal for power regulation purposes. The motors are mounted in an oscillating manner about an axis which is parallel, in particular substantially parallel, to the motor axis but offset with respect to the motor axis in a lateral manner, in particular in a parallel manner.