Derny

The combination allows for smooth acceleration and slowing, important when the rider taking pace is only centimetres from the Derny's rear wheel.

One, the Burdin, was briefly used, but proved neither durable nor fast enough for repeated high-speed riding on the steep tracks used in six-day racing.

Modern machines are made by a small company in Neerpelt, Belgium, and dernys are either new or have the original frames with new 90 cc (5.5 cu in) engines.

The rider sits close to the back in an upright position to provide an envelope of low wind resistance for the cyclist drafting or slipstreaming behind.

Also a roller is added behind the rear of the stayer as safety feature in case the rider bumps into it, and normally the cyclist rides on a bicycle with a slightly smaller front wheel.