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A unicycle is a one-wheeled human powered
vehicle. Unicycles are similar to, but less complex than, bicycles.
Construction
Unicycles comprise a few key parts: the wheel and axle, the frame, the seat, and cranks and pedals. The wheel is the main part of the unicycle; it is essentially a bicycle wheel with a
special hub so that the frame and cranks can attach to the side. Unicycles use direct drive, with the crank's rotation
directly connected to that of the wheel. The frame sits above the wheel, and the seat is located on top of the frame.
Riding
Unicycles are more difficult to ride than bicycles. They require the rider to maintain balance in two dimensions rather than
one, and with their slower speeds their motion has less gyroscopic assistance for
maintaining stability.
Balancing a robotic unicycle forms an interesting problem in
control theory.
History
Unicycles are thought to descend from the penny-farthing bicycles of
the late 19th century. These bicycles had a large wheel in front, to which the pedals were attached, and a much smaller wheel
behind for balance. When these bicycles hit a bump, the rear wheel would come off the ground, forcing the rider to balance on one
wheel. Early unicycle photographs, which show unicycles with very large wheels, support this explanation.
Recent developments
Unicycles have traditionally had circus connotations, but in recent years unicycles
have gained a following as a means of everyday transportation.
Unicycling has also gained popularity as a sport. The bi-annual world championship
UNICON holds Unicycle races. Riding a
unicycle in off-road conditions is known as mountain unicycling, which is similar to mountain biking. In unicycle trials the
unicyclist aims to negotiate a series of obstacles without any part of the rider touching the ground. Freestyle Unicycling
contains a style of tricks seen in skateboarding, aggressive in-line
skating, BMX, and freestyle biking including jumps, spins, and grinds.
Unicycle hockey
In the UK, Unicycle Hockey has become a small, niche sport, with 5-a-side rule (5 members on each team). Games are played at
Uni meets, club meets and the British Unicycle Convention.
Variations
- Giraffe unicycles: tall, chain-driven unicycles.
- Mountain unicycles: unicycles made for the sport of mountain unicycling.
- Kangaroo unicycles:
unicycles with an off-center wheel and cranks that face the same direction. The rider of a kangaroo unicycle appears to be
hopping about like a kangaroo, hence the name.
- Ultimate wheel: a
unicycle with no frame or seat, just a wheel, cranks, and pedals.
- Impossible wheel: a wheel with pegs sticking out for the rider
to stand on. Theoretically, this works like log-rolling.
- Multi-wheeled
unicycle: Still a unicycle since the wheels are stacked on top of each other so only one touches the ground. The wheels are
linked together by chains or friction.
- A quick list of other variations: Tandem, Recumbent, Hydraulic Giraffe, Unibike, Motorized, Suicycle
- Monowheel: a large wheel in which
the rider sits inside (like a hamster wheel) and either pedals an internal drive or is motorized. It is not plagued by the normal unicycle
balance problems because of the greater gyroscopic properties and lower center of mass.
External links
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