Abstract: A bicycle includes a flywheel mounted coaxially and rotatably with respect to a pedal-carrying shaft. The flywheel is drivingly coupled to the rear tractive wheel via a pair of friction wheels mounted in gear train fashion to provide a ratio of at least 1,000 revolutions of the flywheel per revolution of the tractive wheel. One of the intermediate wheels serves as a slip clutch for selective engagement with the tractive wheel. This clutch wheel has its axle mounted in an elongated slot. A bendable arcuate control lever positions the axle along the slot.