This electric bicycle has a battery built into its frame and a small electric motor attached to the back wheel. The motor is not strong enough to power the bicycle alone, but it provides assistance to the rider.
Many other types of bicycles are designed for special purposes. Although not as common as standard single-rider racing, touring, mountain, or recreational bicycles, they nonetheless have significant niches.
Recumbent bicycles are bicycles on which the rider sits upright as if in a chair, with legs and feet stretched out in front. Because they support the rider’s lower back, recumbents allow the rider far more leverage with the thigh muscles. They also have a lower center of gravity. The popularity of recumbents, especially for touring, began increasing in the 1980s.
Tandems are bicycles built to carry two or more riders. The traditional “bicycle built for two” is operated by a captain, or front rider, who controls the steering and the brakes, and by a stoker, or rear rider. The drive train is designed so that both riders may contribute to the pedaling. Tandems are seen in racing as well as in touring and recreational riding, as two riders pedaling in cadence have far faster times than individual riders. Tandems are also useful for introducing visually impaired individuals to bicycling or for touring with children not yet skilled enough to operate a standard bicycle. In these cases, the sighted cyclist or the parent rides as captain.
Agile bicycle-motocross (BMX) bicycles, modeled after the motocross “dirt-bike” motorcycle, are most popular with children and teenagers. BMX wheels are much smaller in diameter than touring or hybrid wheels, and the frame is designed to be very small in relation to the size of the rider.
A recumbent bicycle rider cruises along Valley Parkway in Rocky River, Ohio, on the way home from work.
Freestyle stunt bicycles, which are BMX-style bicycles with a particularly strong frame and handlebars that can spin completely around without being stopped by gear or brake cables, created a whole new sport of freestyling, or bicycle acrobatics. Their design enables riders to maneuver the bicycle by standing on foot pegs that extend from the rear hub, as well as to jump themselves and the bike to great heights and even perform airborne somersaults by throwing their bodies and pulling sharply on the handlebars. Freestyling reached its heyday in the 1980s but is still a feature at special meets.
Collapsible bicycles are useful for commuting and meeting size regulations on public transportation, including airlines. Alexander Moulton in England pioneered the small-wheeled foldable frame in 1962, and by the mid-1990s developers had produced a number of ingenious designs. Some, such as the Montague, are full-sized bicycles that fold. Others, such as the Bike Friday, the Moulton, and the Swift Folder, have very small wheels.