Patent ID: 8434776

Claim:
A shock absorbing bicycle frame ( 1 ) comprising a front frame unit ( 2 , 2 a , 3 , 4 , 5 , 7 ) connected to a bottom bracket shell ( 6 ) by which the drive tension is applied to a drive chain ( 8 ), a rear wheel swing arm ( 13 ) attached to the front frame unit ( 2 , 2 a , 3 , 4 , 5 , 7 ) at a single pivot point ( 30 ) and presenting a mounting end ( 14 a ) to receive a rear axle ( 15 ) of a rear wheel ( 10 ), the distance between the said mounting end ( 14 a ) and the bottom bracket shell ( 6 ) being variable over the full rear wheel travel, characterised in that it further comprises a rear wheel suspension assembly ( 20 ) comprising a compressible shock absorbing unit ( 16 ) connecting the rear wheel swing arm ( 13 ) to the front frame unit ( 2 , 2 a , 3 , 4 , 5 , 7 ) so that to absorb the vertical force applied to the rear axle ( 15 ) of a rear wheel ( 10 ) due to irregularities ( 25 ) of the ground and a chain unit ( 21 ) pivotably mounted on the front frame unit ( 2 , 2 a , 3 , 4 , 5 , 7 ), rigidly connected to both the rear wheel swing arm ( 13 ) and to the drive chain ( 8 ) in order to maintain the drive chain length over the full rear wheel travel and the full variation in the distance between the mounting end ( 14 a ) of the rear wheel swing arm ( 13 ) and the bottom bracket shell ( 6 ), so that the shock absorbing unit ( 16 ) is not affected by the pedalling forces due to the rider pedalling, the said pedalling forces being then not wasted.