Rear suspension of a vehicle with drive wheel borne by an oscillating arm

Rear suspension of a vehicle, such as a bicycle, motorcycle or similar, of the type comprising an underframe (1), a swing arm (15) integral with chassis (1), bearing the hub axle of a drive wheel (19) and a shock absorber (24) whose ends are respectively integral with underframe (1) and swing arm (15), the torque drive being transmitted to the drive wheel (19) via a chain (21) extending between an engaging sprocket (13) integral with underframe (1) and an engaged sprocket (20) integral with the hub axle of drive wheel (19), said chain (21) between the engaging sprocket (13) and engaged sprocket (20) forming two strands, one tensioned upper strand (22) transmitting the torque drive to the drive wheel (19) and a lower strand (23), so-called return strand, underframe (1) being formed of a globally vertical seat tube (2), of a top tube (4) and a down tube (3), top tube (4) and down tube (3) being integral with a head tube (5) bearing a fork (6), and the axle of engaging sprocket (13) being positioned at the intersection between seat tube (2) and down tube (3) and/or swing arm (15) comprising means so that upper strand (22) of transmission chain (21) or the straight line extending the same, passes through the instantaneous centre of rotation C of swing arm (15) when the vehicle is in a position of static equilibrium, and so that said upper strand (22) of chain (21) is positioned below the instantaneous centre of rotation C of swing arm (15) when the hub of drive wheel (19) is positioned above its reference position Pr corresponding to the position of the hub axle of drive wheel (19) when the vehicle is in a position of static equilibrium, characterized in that swing arm (15) is made integral via at least two articulation means (17,18) with underframe (1) whose intersection of straight lines D1,D2 passing through rotation axles (17a,17b,18a,18b) of each articulation means (17,18) is positioned in the upper posterior quadrant of a point defined by a horizontal axis H and a vertical axis V converging towards the axle of the engaging sprocket (13), and in that the ends of shock absorber (24) are respectively integral with swing arm (15) or articulation means (17) joining swing arm (15) to down tube (3) and with a hanger (25) of down tube (3), said hanger (25) extending along the plane containing tubes (2 to 5) of underframe (1), said shock absorber (24) extending in front of down tube (3) i.e. between down tube (3) and fork (6) bearing front wheel (8), globally parallel to the latter or between tubes (2 to 5) forming underframe (1) along the plane containing the latter.