Bicycle

A bicycle, or bike, is a pedal-driven land vehicle with two wheels attached to a frame, one behind the other. First introduced in 19th-century Europe, it evolved quickly into the familiar current design. With over one billion in the world today, bicycles provide the principal means of transportation in many regions and a popular form of recreation and transport in others.

Notes

• 1 Scientific American, March 1973: "Bicycle Technology", by S.S.Wilson.
• 2 "Johns Hopkins Gazette", Aug.30, 1999
• 3 "The Stability of the Bicycle", David Jones, "Physics Today", April 1970: pp.34-40 (external link, below)
• 4 Townsend (external link, below)
• 5 The Economist, Feb.15, 2003
• 6 "Cities for Cyclists" (external link, below)
• 7 "Bicycling Life" (external link, below)
• 8 "John Forester's Effective Cycling" (external link, below)
• 9 See Chapter 9 of "Bicycling Science" (Reference, below) for details of transmission efficiency.