A hub planetary belt transmission (2) has a platform body (50) supporting a motor drive (8) having a motor drive shaft (6) coupled to a distributing and a collecting pulley (4, 18) attached to a first output shaft (22) coupled to a first propulsion element (40, 44). A housing (30) coupled to peripheral shafts (24) attached to tension arms (26) is concentrically rotatable about a common axis of the distributing and collecting pulleys and is coupled to a second propulsion element (42, 45). Transmitting pulleys (12, 14) are driven by distributing belts (10) and collecting belts (20) for rotating together with the peripheral shafts and tension arms about a common axis of the distributing and collecting pulleys so as to create a centripetal force which stretches the distributing belts and the collecting belts, thus regulating the coupling force between the belts and pulleys based on the rotation velocity.