Difference between revisions of "Bicycle"
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[[Image:Bicycle.jpg|right|thumb|300px|Modern bicycle with recommended reflectors for night riding]] | [[Image:Bicycle.jpg|right|thumb|300px|Modern bicycle with recommended reflectors for night riding]] | ||
| − | A '''bicycle''' is a human-powered, two-wheeled conveyance that serves as a popular means of transportation in many nations, and a form of recreation virtually world-wide. A bicycle is also known as a cycle, a bike, or a pedal cycle (this last is to distinguish it from a motorcycle). | + | A '''bicycle''' is a human-powered, two-wheeled conveyance that serves as a popular means of transportation in many nations, and a form of recreation virtually world-wide. Most bicycles are propelled by pedals driven by the rider's feet. A bicycle is also known as a cycle, a bike, or a pedal cycle (this last is to distinguish it from a motorcycle). |
The first recorded "two-wheeler" was the "draisine" designed in 18th century Germany by Baron Karl von Drais, possibly for use in traveling his estate to collect rents from his tenants. Decades later, Scottish blacksmith Kirkpatrick MacMillan added a pedal and chain drive mechanism to create the most credible prototype of the modern bicycle. Subsequent improvements included Englishman J.K. Starley's now-familiar diamond-shaped frame, Dunlop's pneumatic tire, multiple-gear options, and increasingly sophisticated brakes. The basic design of bicycles was relatively unchanged through the first half of the 20th century, but many subtypes of bicycles have subsequently evolved, including the [[racing bike]], [[road bike]] and [[mountain bike]], to suit the needs of specific cyclists. | The first recorded "two-wheeler" was the "draisine" designed in 18th century Germany by Baron Karl von Drais, possibly for use in traveling his estate to collect rents from his tenants. Decades later, Scottish blacksmith Kirkpatrick MacMillan added a pedal and chain drive mechanism to create the most credible prototype of the modern bicycle. Subsequent improvements included Englishman J.K. Starley's now-familiar diamond-shaped frame, Dunlop's pneumatic tire, multiple-gear options, and increasingly sophisticated brakes. The basic design of bicycles was relatively unchanged through the first half of the 20th century, but many subtypes of bicycles have subsequently evolved, including the [[racing bike]], [[road bike]] and [[mountain bike]], to suit the needs of specific cyclists. | ||
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| publisher = Massachusetts Institute of Technology | | publisher = Massachusetts Institute of Technology | ||
| isbn = 0-262-73154-1 | | isbn = 0-262-73154-1 | ||
| − | | pages = pages 342–349}}</ref> | + | | pages = pages 342–349}}</ref> Bicycle tires can also affect efficiency.<ref>{{cite web |
| + | | url = http://www.terrymorse.com/bike/rolres.html | ||
| + | | title = Rolling Resistance of Bike Tires | ||
| + | | accessdate = 2012-01-05}}</ref>Tires with little or no tread and pumped up hard are much more efficient than (mountain-bike style) knobbly tires which are not usually pumped up hard (but the latter may result in a more comfortable ride). | ||
==Electric bicycle== | ==Electric bicycle== | ||
Revision as of 14:26, February 5, 2012
A bicycle is a human-powered, two-wheeled conveyance that serves as a popular means of transportation in many nations, and a form of recreation virtually world-wide. Most bicycles are propelled by pedals driven by the rider's feet. A bicycle is also known as a cycle, a bike, or a pedal cycle (this last is to distinguish it from a motorcycle).
The first recorded "two-wheeler" was the "draisine" designed in 18th century Germany by Baron Karl von Drais, possibly for use in traveling his estate to collect rents from his tenants. Decades later, Scottish blacksmith Kirkpatrick MacMillan added a pedal and chain drive mechanism to create the most credible prototype of the modern bicycle. Subsequent improvements included Englishman J.K. Starley's now-familiar diamond-shaped frame, Dunlop's pneumatic tire, multiple-gear options, and increasingly sophisticated brakes. The basic design of bicycles was relatively unchanged through the first half of the 20th century, but many subtypes of bicycles have subsequently evolved, including the racing bike, road bike and mountain bike, to suit the needs of specific cyclists.
A bicycle can be a very energy-efficient means of transport. A well-maintained chain-driven bicycle can achieve efficiencies of over 98%, though the use of gearing mechanisms may reduce this to as low as 80% in some gears, with hub gears being generally a little less efficient than derailleur gears.[1][2] Bicycle tires can also affect efficiency.[3]Tires with little or no tread and pumped up hard are much more efficient than (mountain-bike style) knobbly tires which are not usually pumped up hard (but the latter may result in a more comfortable ride).
Electric bicycle
An electric bicycle provides power assistance to a bicycle rider, by use of a battery-powered electric motor. The motor is much quieter than an engine, and when mounted in the hub of a wheel it looks like a big drum brake.
References
- ↑ "Johns Hopkins Gazette", 30 August 1999
- ↑ Wilson, David G.; J Papadopuolos (2004). Bicycling Science, Third edition, Massachusetts Institute of Technology, pages 342–349. ISBN 0-262-73154-1.
- ↑ Rolling Resistance of Bike Tires. Retrieved on 2012-01-05.