A belt pulley damper for attenuating torsional vibrations of a drive shaft and includes a belt pulley for driving a pull mechanism, particularly a pulling belt. A torsional vibration damper, particularly a decoupler for torsional vibrations is connected with a drive flange and includes a driven disk movable circumferentially relative to the drive flange, and a driven disk is axially movable relative to a belt pulley. The belt pulley and the driven disk include axially-opposed teeth. The belt pulley teeth and the driven disk teeth can be engaged below a threshold pull force occurring during drive operation, and can be disengaged above the threshold pull force. In that manner, undesired torsional vibrations can be avoided by a free-wheel device without substantially increasing noise.