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A three wheeled car, also known as a tricar or tri-car, is an automobile having either one wheel in the front for steering and two at the rear for power, two in the front for steering and one in the rear for power, or any other combination of layouts. Due to its handling superiority, an increasingly popular form is the front-steering "tadpole" or "reverse trike" sometimes with front drive but usually with rear drive.

History

Early car pioneer Karl Benz developed a number of three-wheeled models. One of these, the Benz Patent Motorwagen, is widely regarded as the first purpose-built automobile, and may be the first petrol car driven on British soil, in 1894. In 1896, John Henry Knight showed a tri-car, recognized as the first British-made motorcar, at The Great Exhibition. A Conti 6 hp Tri-car competed in (but did not complete) a 1907 Peking-to-Paris race sponsored by a French newspaper, Le Matin.

Strengths and weaknesses

Having one wheel in front and two in the rear for power reduces the cost of the steering mechanism, but greatly decreases stability. However, a configuration of two wheels in the front and one wheel at the back has many strong proponents among automotive designers and enthusiasts. Two advantages are its improved aerodynamics, and that it readily enables small lightweight motorcycle powerplants and rear wheels to be used. This approach was used by the BMW Isetta. Alternatively, a more conventional front-engine, front wheel drive layout as is common in four-wheeled cars can be used, with subsequent advantages for stability and traction.

For the lowest wind resistance (which increases fuel efficiency), a teardrop shape is desirable. A tear drop is wide and round at the front, tapering to a point at the back. The three wheel configuration allows the two front wheels to create the wide round surface of the vehicle. The single rear wheel allows the vehicle to taper at the back. This approach is used by the . It is also used by Myers Motors for both its single passenger NmG and upcoming 2-passenger Duo.

Having one less wheel also increases fuel efficiency because of decreased rolling resistance.

The disadvantage of a rear drive, non-tilting three wheel configuration is instability - the car will tip over in a turn before it will slide, unless the centre of mass is much closer to the ground or the wheelbase is much wider than a similar four wheel vehicle. To improve stability some three wheelers are designed as tilting three wheelers so that they lean while cornering like a motorcyclist would do. The tilt may be controlled manually or by computer. Electric three-wheelers often lower the center of gravity by placing the heavy battery pack at the base of the vehicle.

Examples

Registration

In the U.S. the National Highway Traffic Safety Administration defines and regulates three-wheeled vehicles as motorcycles. Licensing requirements vary on a state-by-state basis. In other jurisdictions, such as British Columbia, Canada, a three-wheeled vehicle with an enclosed passenger compartment is considered an automobile.

See also

• Three wheeler
• Tricycle - Motorized tricycles
• Tuk-tuk or Auto rickshaw - Three wheeled vehicles popular in many parts of Asia
• Steam tricycle
• Cushman - manufactured in USA, many built for utility/maintenance
• Tri-Magnum - a DIY three-wheeler
• Myers Motors NmG - all-electric plug-in, manufactured in USA

References

1. ^ Elvis Payne (2001). "The History of the 3-Wheeled Vehicle". pages.zoom.co.uk. Retrieved 2008-01-20.
2. Chris Chong (July 2 2006). "History in its magnificence". star-motoring.com. Retrieved 2008-01-20. {{cite web}}: Check date values in: |date= (help)
3. "History". pekingparisraid.co.uk. Retrieved 2008-01-20.
4. "Advance Fore-Cars and Tri-Cars". oakingtonplane.co.uk. Retrieved 2008-01-23.
5. "British Motor Manufacturers (1894-1960) Humber". britishmm.co.uk. Retrieved 2008-01-20.
6. "Humber - The 1900 's". histomobile.com. Retrieved 2008-01-20.
7. "Rileys 1896 - 1939 The Pre-Nuffield Years". Rob's Riley Pages (ukonline.co.uk/rileyrob). Retrieved 2008-01-20.
8. "The History of Classic Cars: 1905 Lagonda Tricar". autoclassic.com. Retrieved 2008-01-20.
9. H. Roy Jaffe. "The History of Tri-car". The Early Birds of Aviation, Inc. (earlyaviators.com). Retrieved 2008-01-20.
10. "General Motors Three Wheeled Cars". GM's Lean Machine (3-wheelers.com/gmlean). Retrieved 2008-04-08.
11. "Lean Machines: Preliminary Investigation" (PDF). Institute of Transportation Studies, University of California at Berkeley (commutercars.com/downloads/studies/). Retrieved 2008-04-08.
12. "Home Built Three Wheeled Car: Scorpion". Art by Shep (artbyshep.homestead.com). Retrieved 2008-04-08.
13. Template:Http://www.nhtsa.dot.gov/nhtsa/Cfc title49/HighwaySafety.pdf

External links

• History of the Three Wheeler
• "Three Wheel Cars; Primary Factors that Determine Handling & Rollover Characteristics"
• Link index for three wheeled cars as well as other types

• Three-wheeled motor vehicles