There are four general classifications of recumbent bicycles; ones with under seat steering, ones with above seat steering, ones with short wheelbases and ones with long wheelbases. These general classifications can be mixed and matched at the builders whim to form a multitude of variations. The short wheelbase has the rider's pedals in front of the front wheel and the long wheel base has the front wheel in front of the pedals. The rear wheel is usually behind the back of the rider unless the bicycle is built for two riders and is either normal bicycles wheel size or smaller. The front wheel is almost always smaller than conventional bicycle wheel size.
Recumbents are considered to be fast and maneuverable since the rider can push against the seat back on the "down" stroke of the pedal and the low profile of the rider makes it more aerodynamic. Many owners prefer them because they are easier on the hand, arms, shoulders, and butt. A disadvantage of the recumbent cycling position is that a person is unable to stand on ascents and so tends to be slower going uphill than on a conventional bike. Recumbent supporters would point out that they can compensate for this disadvantage by being more aerodynamic. Most riders who switch styles find that they may be slower but they are able to keep riding longer because they experience much less pain.
Because the bike is so low, a flag is often added to the rear end to make it easier to see in traffic. However the unusual appearance of a recumbent often means it is readily spotted anyway.