Unicycles

A unicycle is a one-wheeled human-powered vehicle. Unicycles are similar to, but less complex than, bicycles. 
==History==
One theory of the advent of the unicycle is based on the popularity of the penny-farthing (or "Ordinary") during the late 19th century. Since the pedal and cranks were connected directly to the front axle, the rear wheel would go up in the air and the rider would be moved slightly forward. Many penny-farthing owners discovered they could dispense with the frame and just ride the front wheel and handlebars. Evidence for this theory of development can reportedly be found in pictures from the late 19th century showing unicycles with large wheels.
Over the years, unicycle enthusiasts have inspired manufacturers to create new designs, such as seatless ("ultimate wheel") and tall ("giraffe") unicycles. During the late 1980s some extreme sportsmen took an interest in the unicycle and off-road unicycling (MUni) was born.
==Construction==
Unicycles are composed of a few key parts: the wheel (which includes the tire, tube, rim, spokes, hub and axle), the cranks, pedals, fork-style frame, seatpost, and saddle (the seat of the unicycle). The wheel is usually similar to a wheel with a special hub designed so the axle is a fixed part of the hub. This means the rotation of the cranks directly controls the rotation of the cranks direct drive. The frame sits on top of the axle bearings, while the cranks attach to the ends of the axle. The seatpost links the frame to the saddle.
There are many different types of unicycles, which can include (but are not limited to): freestyle unicycles, trial unicycles, MUnis, giraffes, and long distance unicycles, which all have special components unique to that type of unicycle.
==Training aids==
Having props, or training aids may make it easier to become comfortable with riding a unicycle. Two round wooden poles an inch or two in diameter and up to 4ft long can be used as training poles to stay stable. Another method for training is using a spotter to make riding easier. One other easy way to learn is to find a narrow hallway with which to use to help alleviate your left and right balancing while allowing you to focus on your forward and backward balance.
==Types of unicycles==
*Freestyle unicycle: Generally used for flatland skills and routines. Usually has a relatively high seatpost, a narrow saddle, a squared fork (used for one-footed tricks), and square taper cranks and hub, as they usually do not need to withstand as much pressure as afforded by more expensive splined cranks. These unicycles are used similarly to flatland bicycles. Some examples of freestyle unicycles include Miyata, Nimbus, Schwinn, and Semcycle brands. This type of unicycle is often less expensive than some other types due to the less robust construction. Wheel size is usually 20mm, but smaller riders may use 16mm or 12mm unicycles. Some people prefer 24mm wheels. 
*Trials unicycle : Designed for unicycle trials, trials unicycles are stronger than standard unicycles in order to withstand the stresses caused by jumping, dropping, and supporting the weight of the unicycle and rider on components such as the pedals and cranks. Most modern trials unicycles include splined hubs and cranks, which are stronger and less prone to damage in the event that the crank bolts come loose while riding. This feature was less common in the past, when splined hubs were much more expensive. Many trials unicycles also have wide, 19- or 20mm knobby tires to absorb some of the impact on drops. 
*Offroad unicycle ("muni") :"MUni" or "muni" is an abbreviation for mountain unicycling. MUnis have many of the same components as trials unicycles, but have a few key differences. Usually, the tire diameters on mountain unicycles are either 24 or 26mm, allowing the rider to more easily roll over obstacles such as roots and rocks. The seat is also thicker and more comfortable on MUnis to compensate for the rough terrain. Brakes are sometimes used for steep descents. 
*Touring unicycle : Used for long distances, these unicycles are specially made to cover distances. They have a large wheel diameter, between 26 and 36 in., so more distance is covered in less pedal rotation. A 36" unicycle made by the Coker Tire company started the big wheel trend. Some variations on the traditional touring unicycle include the Schlumpf "GUni" (geared unicycle), which uses a two-speed internal fixed-geared hub. Larger direct-drive wheels tend to have shorter cranks to allow for easier cadence and more speed. Geared wheels, with an effective diameter larger than the wheel itself, tend to use longer cranks for control, as the speed comes from the gear ratio, not the wheel itself.
=== Variations ===
*Giraffe: A chain-driven unicycle, which allows the unicycle to be much taller than standard unicycles (note that multi-wheel unicycles can be described as giraffes). Standard unicycles don't have a chain, which limits the seat height based on how long the rider's legs are, because there the crank is attached directly to the wheel axle.
*Geared unicycle ("GUni"): A unicycle whose wheel rotates faster than the pedal cadence. They are used for distance riding and racing.
*Multi-wheeled unicycle : A unicycle with more than one wheel, stacked on top of each other so that only one wheel touches the ground (nicknamed stacks). The wheels are linked together by chains or direct contact with each other.
*Kangaroo unicycle: A unicycle that has both the cranks facing in the same direction. They are so named due to the hopping motion of the rider's legs, supposedly resembling the jumping of a kangaroo.
*Eccentric unicycle: A unicycle that has the hub off-center in the wheel. Putting an ecentric wheel on a Kangaroo unicycle can make riding easier, and the rider's motion appear more kangaroo-like.
*Ultimate wheel: A unicycle with no frame or seat, just a wheel and pedals.
*Impossible wheel (BC wheel) :A wheel with pegs or metal plates connected to the axle for the rider to stand on. These wheels are for coasting and jumping. A purist form of unicycling. There are no cranks.
*Monocycle: A large wheel inside which the rider sits (as in a hamster wheel), either motorized or pedal-powered. The greater gyroscopic properties and lower center of mass make it easier to balance than a normal unicycle but less maneuverable.
*Eunicycle: A computer-controlled, motor-driven, self-balancing unicycle.
*Freewheeling unicycle: A unicycle in which the hub has a freewheel mechanism, allowing the rider to coast or move forward without pedaling, as a common bicycle does. These unicycles almost always have brakes because they cannot stop the way traditional unicycles do. These unicycles also cannot go backwards.
*Other variations include tandem, recumbent, hydraulic giraffe, unibike, suicycle, and motorized unicycle.
==Theory==
A unicycle is a form of inverted pendulum. It is also a nonholonomic system because its outcome is path-dependent. Balancing a robotic unicycle or a Eunicycle forms an interesting problem in control theory.
==Riding styles==
Traditionally, unicycling has been connected with parades or the circus. Recent developments in the strength and durability of bicycle (and consequently unicycle) parts have given rise to many riding styles such as trials unicycling and mountain unicycling. Unicycling has therefore developed from primarily an entertainment activity to a competitive sport and recreational pursuit.
*Freestyle: Perhaps the oldest form of extreme unicycling. Traditional freestyle riding is based around performance. Freestyle tricks and moves are derived from different ways of riding the unicycle, and linking these moves together into one long flowing line that is aesthetically pleasing.
*Trials unicycling: Trials unicycling is specifically aimed at negotiating obstacles. Analogous to trials bike riding. 
*Street unicycling: Street unicycling is a style of unicycling where riders use combination of objects found in urbanized settings, such as ledges, handrails, and stairs to perform a wide variety of tricks.
*Off-road or mountain unicycling (MUni): Unicycling on rough terrain has been the swiftest growing form of unicycling in recent years. Any place a mountain bike can go, a mountain unicycle can go as well — and sometimes more easily, due to the unicycle's greater maneuverability.
*Touring or commuting: This style is meant for distance riding. With a 29mm or 36mm wheel cruising speeds of 10 to 15km can easily be reached. However, the smallest wheel diameter to fit within the "touring" category is 26mm.
*Flatland: Flatland is a relatively new form of unicycling derived from a combination of street and freestyle riding. By definition it follows the same rules as freestyle: to do various trick and move on flat ground. Flatland, however, has a distinctly urban flair to it.
*Gliding: Riding with one foot on the wheel and the other foot resting on the frame, maintaining balance only by the braking action of the foot on the wheel.
*Coasting: Freewheeling or maintaining movement with both feet on the frame (no power and no braking action).
===Unicycle team sports===
In addition to individual efforts, team sports played on unicycles have also grown in popularity.
====Unicycle basketball====
Unicycle basketball is played using a regulation basketball on a regular basketball court with the same rules, e.g., one must dribble the ball whilst riding. There are a number of rules that are particular to unicycle basketball as well, e.g., a player must have at least one foot on a pedal when in-bounding the ball. Unicycle basketball is usually played using 24" or smaller unicycles, and using plastic pedals, both to preserve the court and the players' shins. In North America, regular unicycle basketball games are organized in Berkeley Phoenix, Minneapolis, and Toronto. Also, Puerto Rico fields a team which has won several world championships.
====Unicycle hockey====
Unicycle hockey is played according to rules basically similar to ice hockey or inline hockey, using a tennis ball and ice-hockey sticks. Play is non-contact. The sport is growing in popularity, with active leagues in Germany, Switzerland and the UK.
====Unicycle handball====
Unicycle handball is played with use of a handball-sized ball. The teams aim to throw it into a vertical hoop placed about 6ft above the ground It has been played in the Polish village of Chrzelice since late 1970s.
==Video Clip==
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==Equipment and safety==
*Wrist guards: The most common impact points when falling from a unicycle are the hands and wrists. Of all the safety gear, wrist guards receive the most wear and tear. 
*Knee and elbow pads: The second most common impact point are the knees followed by the elbows. Knee pads are required for events like racing and MUni.
*Helmet: A helmet is especially important with specialty riding like MUni, and in some jurisdictions is required for road riding as well as racing, MUni and other events.
*Shin guards: Shin guards become a necessary piece of equipment when using metal or pinned pedals. These types of pedals grip the shoes better, but can cause injury to the legs.
*Cycling shorts: Padded cycling shorts are designed with a seamless, padded crotch, and long enough legs to extend down past the saddle, making them much more comfortable than "normal" shorts.
*Gloves: Gloves are required for certain unicycling events such as racing. Gloves may be fingerless (but are not recommended).