A pedal for bicycles includes a pedal pin that extends along a reference axis and has a first axial end structured to be coupled to a pedal crank of a bicycle and a second axial end opposite to the first end and a pedal body that comprises a hub coupled in a freely rotatable manner to the pedal pin so as to be able to rotate around the reference axis. On the pedal pin there are at least two inner chambers having a circular section and extending along the reference axis coaxial thereto, a sensor circuit coupled to the pedal pin, an electronic circuit configured to determine the mechanical deformation of the pedal pin, and an electric storage device arranged in an inner chamber.