Abstract: A propulsion system includes a first torque transmission element and a second torque transmission element, the first torque transmission element being adapted to transmit torque to the second torque transmission element. The propulsion system further includes a first torque transmission element crank coupled to the first torque transmission element by a bearing arrangement that transmits torque to the first torque transmission element when the first torque transmission element crank is turned in a first rotational direction about an axis of the first torque transmission element and that permits the first crank to be turned freely relative to the first torque transmission element when the first torque transmission element crank is turned in a second rotational direction. A vehicle comprising a propulsion system and a bicycle are also disclosed.