Tandem bicycle
The tandem bicycle or twin is a form of bicycle designed to be powered by more than one person. Originally the tandem was composed of welding two bicycle frames together to form a two-person bicycle. Modern technology has improved component and frame designs and many tandems are as well-built as modern high-end road and off-road bikes. Because of the additional stresses caused by multiple riders, tandems typically have stronger components than ordinary bicycles.
While a tandem has double the pedalling power, it has about the same wind resistance as a single bike. It also has less than double the weight, so the power to weight ratio is higher than a single rider bicycle. These factors can make them very fast, especially downhill. The front rider steers the bicycle and is known as the captain, pilot, or steersman; the rear rider is the stoker, navigator or rear admiral. On most designs of tandem the two sets of pedals are mechanically linked and turn at the same rate: some designs have independent pedals.
Beyond tandems is the world of multi-bikes. Bicycles for three, four, or five riders are "triples" or "triplets", "quads" or "quadruplets", and "quints" or "quintuplets" respectively. A famous ten-person bicycle or "decemtuplet", the "Oriten", was built in 1896 by the Orient Cycle Company. Perhaps the largest bicycle ever built was the 40-seater built in 1984 in Queanbeyan, Australia.
Tandem bicycles are often used in competitions for blind and vision-impaired cyclists, who ride as stokers with a fully-sighted pilot.
de:Tandem (Fahrrad) fr:Tandem nl:Tandem ja:タンデム