0 a bicycle with a motor, used to set the pace (= speed) in some bicycle racing events such as the keirin
Always held on a cycling track, the riders follow a derny throughout the race.
For most derny races, the cyclist sits in the slipstream for the duration of the event.
A coupling between the motor and the back wheel ensures the derny will not stop dead if the motor seizes.
In 1899 electric tandems were tried and motor (derny) pacing was used in 1950.
The race started at night and continued, from soon after dawn, behind derny motorcycle pacers.
The name "derny" is now applied to all such vehicles, regardless of manufacturer.
Some riders train behind a derny on the road.
The rider of the derny is known as their pacer.
