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  Wikipedia: Bicycle

Wikipedia: Bicycle
Bicycle
From Wikipedia, the free encyclopedia.

A bicycle is a small land vehicle with two tandem wheels (hence the name) powered by a seated human rider (occasionally more than one - see variations below) -- in other words a pedal vehicle. Cycling or riding bicycles is one of the principal forms of transportation in several parts of the world. It is also a common recreation and popular sport.

The bicycle is the most energy efficient means of transport known to man. It has been calculated that, in terms of converting food energy to motion, a bicycle is the most efficient form of locomotion found anywhere in biology. See Science of Cycling: Human Power: page 1.

It is also the trademark of Bicycle Playing Cards.

Speed

Typical speeds for bicycles are 16-32 km/h (10-20 mph). On a really fast racing bicycle, a reasonably fit rider can ride at 30 mph or 50 km/h on the flat for short periods. The highest speed ever attained on the flat, without riding behind a wind-block, is by Canadian Sam Whittingham, who in 2001 set a 80.55 mph or 142.51 km/h record on his highly aerodynamic recumbent bicycle. This stands as the record for all human-powered vehicles.

History

There is some debate about who invented the first bicycle or precursor to the bicycle. Pierre and Ernest Michaux are often credited, but another Frenchman Comte Mede de Sivrac probably has the strongest claim, with the "celerifere" machine he produced in 1790.

The first successful machines that resembled bicycles were invented in the early 1800s. The German Karl Drais also has a claim with a "Laufmaschine" or "walking machine", which he exhibited in Paris in 1818. The "draisine" of 1817 had two inline wheels connected to a wooden frame by forks, and the front wheel was steerable. It became rather popular, especially in England and America.

The draisine and machines like it went by a variety of names, such as hobby horse, dandy horse, biciped or swift walker. They were more like scooters than bicycles, because the only means of propulsion was to push against the ground.

In 1840 the Scottish blacksmith Kirkpatrick McMillan designed and built the first rear-drive bicycle with pedals and cranks, and can therefore be credited as the inventor of the modern bicycle. MacMillan called his machine a "velocipede", and rode it the 40 miles from his home to Glasgow. On his approach to the city, crowds gathered on the road and unfortunately Kirkpatrick collided with a young girl. Although she was only very slightly injured, he was subsequently charged with causing the first ever bicycle accident. The judge could not believe Kirkpatrick had travelled the 40 miles to Glasgow in only 5 hours, but after much explaining, he was allowed to return home. Kirkpatrick McMillan never patented his designs, and his key role in the development of the modern bicycle has been largely unrecognised.

Machines similar to the "velocipede" became very popular after 1866, which is when Pierre Lallement obtained a US patent for a machine he called the "bisicle". Others called it a "boneshaker", an appropriate name for a contraption with steel-rimmed wooden wheels.

Solid rubber tires appeared in 1869 and improved the ride somewhat. The front wheel got bigger, and the rear wheel got smaller. A bicycle boom began. The first highwheeler or 'Ordinary' appeared in 1872. This was called a "Penny Farthing" in England (a penny representing the front wheel, and a much smaller coin, the farthing, representing the rear wheel).

Since a large wheel went farther for each turn of the cranks, and since the maximum pedalling speed was limited, the larger the wheel, the faster a rider could go. Some of the highwheelers had wheels nearly 60" in diameter. They were fast. They weren't particularly safe. The rider was way up in the air and travelling at a great speed. If he hit a bad spot in the road he could easily be thrown over the front wheel and be seriously injured or even killed. "Taking a header", which was not all that uncommon, was no joking matter. The dangerous nature of these bicycles, meant that cycling was the preserve of adventurous young men (there were no women riders) and had little appeal to the wider public.

In 1884, J. K. Starley of the Coventry Sewing Machine Company, invented the "safety bicycle" with wheels of moderate size and a chain drive. With the rider sitting far back on the bicycle, it was almost impossible to take a header on such a machine. With the front chainwheel larger than the rear sprocket, the rear wheel turned faster than the cranks, making it possible for a chain-driven bicycle to go fast even without a huge wheel.

John Boyd Dunlop invented the pneumatic tyre in 1888. This made for a much smoother ride.

The safety bicycles of 1890 were very much like today's bicycles. They had pneumatic tyres similar in size to those on a modern bicycle, spoked wheels, a steel frame and a chain drive. About all they didn't have was a method of changing the gears.

In the 1890s the new safety bicycle broadened the appeal of cycling. In addition, bicycles became mass produced, bringing bicycles down in price to a point where ordinary working people could afford one. Bicycle racing was a huge spectator sport both in Europe and the USA, pulling crowds of 40,000 or more, who wanted to see superstars such as John S. Johnson or Major Taylor. This fuelled a "bicycling craze", which ushered in a social revolution see below.

Multi-ratio gearing systems were present in racing bicycles by the 1930s, and derailleur systems evolved in the 1950s.

Social & Historical aspect

Socially, the bicycle helped to strengthen the gene pool for rural workers. It tripled their courting radius on the one day per week they had off and thus was a factor in reducing rural inbreeding. The two-wheeled, diamond-frame safety bicycle (basically the same one we ride today) gave women unprecedented mobility, and contributed to their emancipation. In the 1890s the craze for cycling amongst women, created a whole new set of fashions such as "bloomers" (a garment which is a cross between a skirt and trousers (pants)). which helped liberate women from the corset, and other restrictive clothing.

In cities, bicycles helped reduce the crowding in inner-city tenements by allowing workers to commute from single-family dwellings in suburbs. They helped reduce people's dependence on horses. They allowed people to travel in the country. They were three times as efficient as walking and three to four times as fast. Moreover, in terms of distance and speed travelled compared to energy consumed, the bicycle is the most efficient machine yet created.

On an historical note, the development of the modern bicycle had two important implications. First, manufacture of the double-diamond-frame safety bicycle required the development of advanced metalworking techniques to produce the frames, and components such as ball bearings, washers and sprockets. These techniques later enabled skilled metalworkers and mechanics to develop the components that were used in early automobiles and aircraft. The best examples were the Wright Brothers, who got their start as bicycle mechanics.

The second major implication of the bicycle was the political organization of bicycle riders and enthusiasts in such groups as the League of American Wheelmen, in order to persuade local and state governments to create a system of well-maintained and mapped paved roads. Both the model of political organization and the roads themselves later facilitated the growth in the use of another type of wheeled vehicle, the automobile.

In some Western societies, after World War II the bicycle was largely relegated to a device for children, particularly in the United States. In some western countries, most notably Northern European ones such as the Netherlands, Germany, and Denmark, bicycle use for transportation remained fairly common. Interest has gradually returned elsewhere, mostly as a fitness activity, hobby, and competitive sport. More and more people are also using it as a short-range transportation tool, particularly in large, densely populated cities where slow vehicle traffic, high registration and parking costs, and environmental concerns have made commuting by automobile less attractive. This trend has been accelerated by the process of "gentrification" of the inner suburbs of many cities. Many cities are now providing cyclist-only lanes on roads, as well as cycle trails, for both commuting and hobbyist cyclists.

The bicycle remains a primary means of personal transportation in many developing countries. The image of Asian cities clogged with bicycles is a common stereotype, though as they become wealthier it is becoming less popular. According to the magazine, The Economist, one of the major reasons for the proliferation of Chinese-made bicycles on foreign markets is the increasing preference of its own citizens for cars and motorcycles.

Other transportation methods attempt to accommodate the local use of bicycles by providing attachment points on busses, trains, etc. To cope with frequent theft, many destinations provide bike racks or lockable bike mini-garages.

Bicycles and War

The bicycle, unlike the horse, was never suited for use in actual combat. Unlike the massive horse, the bicycle "steed" is light, and cannot sustain the rider's swing of a sword, or the recoil of a gun. The bicycle however can serve as a horse does for "mounted infantry" - in which the troops use the bicycle for transport only, and dismount before fighting.

Late in the 19th century, the American Army tested the bicycle's suitability for cross-country transport of troops. "Buffalo soldiers" stationed in Montana rode the bicycle across roadless landscapes for hundreds of miles with impressive speed.

In 20th century wars, armies without full mechanization used the bicycle as a logistical support. In the Boer War, for example, both sides used the bicycle for scouting. In the First World War, France and Germany used the bicycle as a supplementary way to move troops.

In the Second World War, Germany used the bicycle as an extensive supplement to mechanized transport. In the invasion of Poland, the mechanized forces of Germany were not sufficient to sustain the blitzkrieg without the secondary, follow-up support of transport by horse and bicycle. Late in the war, as German transportation logistics broke down, some ad hoc units used the bicycle in defense and retreat.

Early in the Second World War, Japan used thousands of bicycles stolen from the native population in a campaign against a British colony in Asia. The bicycle allowed quiet and flexible transport of thousands of troops to surprise and confuse the defenders. At the same time it made basically no logistical demands on the Japanese war machine--not for trucks, nor ships to transport them, nor precious petroleum.

Allied use of the bicycle in World Word II was small, but included folding bicycles given to British and American paratroopers, and messengers behind friendly lines.

In the Vietnam War, the communist forces used the bicycle extensively as a cargo carrier along the Ho Chi Minh Trail. Typically loaded with hundreds of pounds of supplies, the bicycle would actually not be rideable. Rather, a tender would walk alongside the bicycle, pushing it, somewhat like a wheelbarrow. With the cargo too bulky to allow the tender to reach the handlebars, they sometimes attached long bamboo poles for tiller-like steering.

The only country to maintain a division of bicycle troops in the past decades was Switzerland. However, they eliminated the remaining division a few years ago.

There seem to be isolated incidents of the use of the mountain bike as a scouting vehicle for U.S. Special Forces in the invasion of Afghanistan and battles against the Taliban.

Technical aspect

All modern bicycles are largely similar, consisting of a number of easily identified parts. The frame is the major part of the bicycle, typically consisting of a large triangle on which the rider's weight is distributed fore and aft, and a smaller triangle at the rear onto which the rear wheel is mounted. The front wheel is attached to the bike with a fork, the top of which runs through a bearing system known as the head set on the front of the frame. There is attached to the stem, an adaptor that is in turn attached to the handle bars. Many modern mountain bikes no longer have a rear triangle, but use a fork-like system on the rear as well, with both forks on suspension systems for a smooth ride over rough ground.

Power is taken from the feet on the pedals, through the cranks which are attached to the bike on a bearing system known as the bottom bracket. A gear (typically more than one) attached to the crank known as the chainring drives the chain, which runs to the rear of the bike. There a second set of gears, known collectively as the cassette, drives the rear wheel. Depending on the type of cycling the bike is designed for, the cassette may be "flat" as on a road bike, meaning that the differences from one gear to the next are 1 tooth apart, or much more varied as on a mountain bike. The entire system from pedal to rear wheel is known as the drive train, and the gear sets have far too many alternative names; front and rear, driving vs. driven, etc.

Allowing for changing gears is one of the major advances in cycling. The legs work best at particular rotational speeds, known as cadence, and having a wider selection of gear ratios allows you to keep the pedaling speed closer to that chosen value. This is why road bikes use gearing that is close-set, in order to allow the rider to keep the cadence well controlled on the smaller set of terrain a road cycle will typically see. The derailleur is a simple devices that puts strain on the chain by pushing it to the side. The sides of the gears themselves are patterned with chain-like indentations that "catch" the chain when it is pushed against them, pulling it up onto its teeth. The system is considerably simpler than earlier gear-chaning systems like the three-speed bicycle, but took longer to come to market because it is considerably different than any common gearing system in prior use.

The last major component of a bicycle is the brakes. Since the 1950s almost all brake systems were patterned off of the Campagnolo side-pull system, in which two calipers are squeezed together by a cable running from the brake handles. The brake places even pressure on either side of the wheel by way of a spring in the middle that centers them. The increasing use of larger tires on mountain bikes presented a problem however, as the wheels were too large to fit inside calipers of moderate size and weight. This was first solved by the introduction of cantilever systems, in which two "half calipers" are attached to each other with a cable, which is in turn attached to the brake cable the rider pulls using the brake lever. This design had several disadvantages however; without careful placement of the connector from the brake cable to the connecting cable, the brakes would put uneven pressure on either side of the wheel, and if the connector loosens completely the cable can drop into the tire tread, thereby causing a quick trip to the hospital when the front wheel instantly stopped turning. A more suitable solution is the v-brake, where the brake cable runs across the top in a way that cannot drop onto the tire, as well as providing considerably more power and being somewhat easier to center.

As of the late 1990s, disc brakes have become commonplace on medium- and high-end off-road bicycles. They are still uncommon on road bikes, where the additional stopping power and higher weight are less desirable.

Materials used in the construction of bicycles are similar to those in aircraft, the goal in both cases to make a strong and light weight structure. Almost all bicycles before the 1970s used chromaloy (or chromoloy), a fairly typical chrome-steel. Starting in the 1980s aluminum started to become popular, largely as a side-effect of its decline in price, and today it is perhaps the most common material used in mid-range bikes. At the high end carbon fibre and titanium are available, although very expensive. Each frame material has certain advantages and disadvantages, although for a given frame geometry all bicycles will have nearly identical ride qualities. The primary differences among frame materials are in the areas of durability, aesthetics, reparability, and weight. Because the vertical stiffness of even a very flexible frame is an order of magnitude higher than the stiffness of the tires and saddle, ride comfort is more a factor of saddle choice, frame geometry, tire choice, and bike fit.

Although the operation of a bicycle is simple in principle, many of the parts are complex and some people prefer to leave repair and maintenance to professionals. However, many prefer to maintain their own bicycles as much as they can, whether to save money or because they enjoy repairs as part of the hobby of cycling.

For more information on the technical aspects of bicycles, see the following:

Variations

Variations on the bicycle include:

And maybe at least one reference to a sports science article that explains how cycling is the most efficient form of human powered transport.

Powered bicycles are also known as motorcycles, mopeds, and scooters.

Bicycle Efficiency

The bicycle is the most technically efficient transportation machine ever invented, in terms of the ratio of distance travelled to the calories of energy spent to achieve that distance.

The bicycle is the most efficient cargo transportation machine ever invented, as defined as the ratio of maximum transported cargo weight to total weight.

Bicycle Lighting

There are several types of bicycle lights available. In the U.S., most commuters choose to use high power halogen lights, which operate from a rechargeable battery. In parts of Europe, low power lights that operate from a dynamo are still popular, but are slowly being replaced by safer, higher power, battery operated halogen lights. Front LED lights are useful for being seen, but do not project a good beam for illuminating the road.

For rear lights, LED flashers are popular in the U.S., but illegal in most other countries. A better choice for a rear lamp, where flashing lamps are legal, is a xenon strobe, because it is less directional.

Many cycle commuters build their own lighting systems with commonly available lamps, batteries, and chargers.

Conflict with Automobiles

Urban bicycle transportation and automobile transportation seem to be mutually antagonistic. Between the two, the growth of one form of transportation seems to be related to a decline of the other. Cyclists and automobile drivers make different sorts of demands on urban design. Since urban space and resources are limited, conflict occurs--in politics and on the streets.

Shanghai, a city once famous for its dominant bicycle transportation, banned bicycle travel on its roads in December, 2003.

Bicycle Activism

"Critical Mass" is a worldwide phenomena of mass bike protest rides. Non-hierarchal, with an emphatic lack of formal organization, the participants ride in a highly visible manner to point out and protest the problems of automobile-dominated culture. (There were 500 million automobiles on the world in 2003.) Critical Mass rides began in the early 1990s in San Francisco and quickly spread around the world.

Bicycle Culture

There are sub-cultures of bicycle enthusiasts in many cities including racers, bicycle messengerss, bicycle transportation activists, bike mechanics, peace and justice activists, and various counter-culture groups. Group activities may involve competitive cycling, fun rides, or civil disobedience. Some groups work to promote bicycle transportation (Yellow Bike Program), such as fixing up bikes to give to children, the homeless, or poor people in another country (Bikes Not Bombs).

Bicycle Culture includes arts and crafts, both handmade and mass manufactured. it also includes a literature of books and magazines. H. G. Wells was an early contributor to Bicycle Culture with his novel "Wheels of Chance".

Cities famous for being "bike friendly" (such as Amsterdam) include a general sense of "Bicycle Culture" as part of the urban identity. Bicycle magazines and organizations give yearly awards to cities for being "Bicycle Friendly".

Bicycles & Urban Design

Bicycles & Health

See also

External links


  

From Wikipedia, the free encyclopedia. 
Modified by Geona