Derny
A Derny is a type of motorcycle designed and built specifically for motor-paced track cycling events (motor-paced road, 6-Day and Keirin racing). On a Derny, the driver sits close to the back of the bike in an upright position in order to block the "wind" for the cyclist drafting behind the derny. There is a "roller" mounted to the rear of the bike to prevent crashes should the bicycle come in contact with the derny.In some events, the derny is used to bring the bicycle up to speed at which point the derny "pulls off" and the cyclist continues the race on their own. For other events, the cyclist drafts off the derny for the durration of the event. For world speed records, the bicycles generally do not have the ability to change gears and the gearing is too high to allow the cyclist to start from a stop without assistance.
The first Dernys were built by Roger Derny and Sons of Paris, France in 1938. That firm is no longer in business and the name "Derny" is now applied to all such vehicles, regardless of manufactuerer.
Bicycles built specifically for drafting behind a derny are called Stayers.
