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How do bicycles operate?

A bicycle’s performance, in both biological and mechanical terms, is extraordinarily efficient. In terms of the amount of energy a person must expend to travel a given distance, investigators have calculated it to be the most efficient self-powered means of transportation. In terms of the ratio of cargo weight a bicycle can carry to total weight, it is also a most efficient means of cargo transportation.

Mechanical efficiency

From a mechanical viewpoint, up to 99% of the energy delivered by the rider into the pedals is transmitted to the wheels (clean, lubricated new chain at 400W), although the use of gearing mechanisms reduces this by 1-7% (clean, well-lubricated derailleurs), 4-12% (chain with 3-speed hubs), or 10-20% (shaft drive with 3-speed hubs). The higher efficiencies in each range are achieved at higher power levels and in direct drive (hub gears) or with large driven cogs (derailleurs).

Energy efficiency

A human being traveling on a bicycle at 16–24 km/h (10–15 mph), using only the power required to walk, is the most energy-efficient means of human transport generally available. Air drag, which increases with the square of speed, requires increasingly higher power outputs relative to speed, power increasing with the cube of speed as power equals force times velocity. A bicycle in which the rider lies in a supine position is referred to as a recumbent bicycle or, if covered in an aerodynamic fairing to achieve very low air drag, as a streamliner.
On firm, flat ground, a 70 kg (150 lb) person requires about 60 watts to walk at 5 km/h (3.1 mph). That same person on a bicycle, on the same ground, with the same power output, can travel at 15 km/h (9.3 mph) using an ordinary bicycle, so in these conditions the energy expenditure of cycling is one-third of walking.

Typical speeds

In utility cycling there is a large variation; an elderly person on an upright roadster might do less than 10 km/h (6.2 mph) while a fitter or younger person could easily do twice that on the same bicycle. For cyclists in Copenhagen, the average cycling speed is 15.5 km/h (9.6 mph).
On a racing bicycle, a reasonably fit rider can ride at 40 km/h (25 mph) on flat ground for short periods

Reduction of weight and rotating mass

There has been major corporate competition to lower the weight of racing bikes in order to be faster uphill and accelerating. The UCI sets a limit of 6.8 kg on the minimum weight of bicycles to be used in sanctioned races

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A brief history of bicycling

The dandy horse, also called Draisienne or laufmaschine, was the first human means of transport to use only two wheels in tandem and was invented by the German Baron Karl von Drais. It is regarded as the modern bicycle’s forerunner; Drais introduced it to the public in Mannheim in summer 1817 and in Paris in 1818. Its rider sat astride a wooden frame supported by two in-line wheels and pushed the vehicle along with his/her feet while steering the front wheel. The 1860s captured the realease of Velocipede or Boneshaker – a two-wheeled bicycle with pedals and cranks on the front wheel. It was known as the bone shaker because the combination of a wood frame and metal tires made for a very uncomfortable ride over cobblestone streets. See what happened next on the list:
[iconlist icon=”check” color=”#00000″]
[li title=”1870s—High-wheeled bicycle: One of the first models to be called a ‘bicycle’ (after its two wheels). The high wheel allowed the rider to travel farther with a single rotation of the pedals. Moreover, a metal frame and rubber tires provided a more comfortable ride than the boneshaker.” icon=”fa fa-check”][/li]
[li title=”1885—Rover Safety bicycle: Invented by John Kemp Starely, England; Featured a strong enough metal to make a chain, plus it had two same-sized wheels and a similar frame to today’s bicycles.” icon=”fa fa-check”][/li]
[li title=”1888—Pnuematic tires: Invented by John Boyd Dunlop, Ireland; Develops air-filled tires that provide a smoother ride than the previously used hard-rubber tires.” icon=”fa fa-check”][/li]
[li title=”1920s—Kid’s bicycles become popular.” icon=”fa fa-check”][/li]
[li title=”1940s—Built-in kickstands developed.” icon=”fa fa-check”][/li]
[li title=”1960s—Racing bicycles become popular and feature dropped handlebars, narrow tires, numerous speeds and a lighter frame.” icon=”fa fa-check”][/li]
[li title=”1980—Spurred by mountain biking and extreme sports, mountain bicycles become a popular consumer item and feature sturdier frames, larger wheels and flat handlebars.” icon=”fa fa-check”][/li]
[li title=”1996—Mountain bicycles appear in the Olympics.” icon=”fa fa-check”][/li]
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It’s a long way from there to now. Seeing how bicycle develops through time, we know to appreciate what we are having to day and how society grows. Let spend some time to be thankful.