A shock absorbing bicycle frame includes a front frame unit connected to a bottom bracket shell by which the drive tension is applied to a drive chain, a rear wheel swing arm attached to the front frame unit at a single pivot point and presenting a mounting end to receive a rear axle of a rear wheel. The distance between the mounting end and the bottom bracket shell is variable over the full rear wheel travel. The frame further includes a rear wheel suspension assembly including a compressible shock absorbing unit connecting the rear wheel swing arm to the front frame unit and a chain unit pivotably mounted on the front frame unit, rigidly connected to both the rear wheel swing arm and to the drive chain to maintain the drive chain length over the full rear wheel travel so that the shock absorbing unit is not affected by pedalling forces due to the rider pedalling, the pedalling forces being then not wasted.