A shock absorbing bicycle frame (1) comprises a front frame unit (2,2a,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 (2,2a,3,4,5,7) at a single pivot point (30) and presenting a mounting end (14a) to receive a rear axle (15) of a rear wheel (10). The distance between the said mounting end (14a) and the bottom bracket shell (6) is variable over the full rear wheel travel. The said shock absorbing bicycle frame (1) 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 (2,2a,3,4,5,7) and a chain unit (21) pivotably mounted on the front frame unit (2,2a,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, 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.