Abstract: The present invention relates to a saddle-riding type vehicle (1) comprising a frame (2) extending mainly along a longitudinal direction (L) and comprising a front portion (2A), a central portion (2B) and a rear portion (2C). The vehicle comprises a powertrain connected to the frame (2) and comprising at least one electric motor (11) operatively connected to at least one driving wheel (9). The vehicle also comprises an electrical power supply assembly suitable for powering said electric motor (11) so as to allow the traction of the vehicle (1) and comprising at least one first pair of batteries (12, 12?) arranged on opposite sides with respect to a longitudinal center plane (a) of the vehicle (1), orthogonal to the axis of rotation of said at least one driving wheel (9).

Abstract: Apparatus for changing bicycle gear ratios comprising pedals (1) to the shaft (3) of which a group of coaxial overdrive gears is fixed, with at least an overdrive gear (20) of larger diameter and at least an overdrive gear (2) of smaller diameter; a plurality of sprockets (4) of different diameter, pack-like disposed close to each other and mounted on the shaft (40) of the rear wheel; a roller chain for the transmission of motion from one of the overdrive gears (2; 20) to one of the sprockets (4); a mechanism for shifting the chain (5) from one to another of said sprockets (4), with a cyclist-operated lever-and-wire driving mechanism; and a mechanism for guiding the deviation of the chain (5) from one to the other of the overdrive gears (2; 20) in cooperation with the mechanism for shifting the chain (5) over the sprockets (4) of the rear wheel. The teeth of each overdrive gear exhibiting, in correspondence of a respective sector (M, N), reduced height and thickness with respect to the other teeth.