A three-wheeler is a vehicle with three wheels. Some are motorized tricycles, which may be legally classed as motorcycles, while others are tricycles without a motor, some of which are human-powered vehicles and animal-powered vehicles.

Overview

Many three-wheelers which exist in the form of motorcycle-based machines are often called trikes and often have the front single wheel and mechanics similar to that of a motorcycle and the rear axle similar to that of a car. Often such vehicles are owner-constructed using a portion of a rear-engine, rear-drive Volkswagen Beetle in combination with a motorcycle front end. Other trikes include ATVs that are specially constructed for off-road use.

Three-wheelers can have either one wheel at the back and two at the front (2F1R), (for example: Morgan Motor Company) or one wheel at the front and two at the back (1F2R) (such as the Reliant Robin). Due to better safety when braking, an increasingly popular form is the front-steering "tadpole" or "reverse trike" sometimes with front drive but usually with rear drive. A variant on the 'one at the front' layout was the Scott Sociable, which resembled a four-wheeler with a front wheel missing.^[1]

Three-wheelers, including some cyclecars, bubble cars and microcars, are built for economic and legal reasons: in the UK for tax advantages, or in the US to take advantage of lower safety regulations, being classed as motorcycles. As a result of their light construction and potential better streamlining, three-wheeled cars are usually less expensive to operate.^{[citation needed]}

Three-wheeler transport vehicles known as auto rickshaws are a common means of public transportation in many countries in the world, and are an essential form of urban transport in many developing countries such as India and the Philippines.

Auto rickshaws are a form of novelty transport in many Eastern countries.^{[citation needed]}

History

Early automotive pioneer Karl Benz developed a number of three-wheeled models.^[2] One of these, the Benz Patent Motorwagen,^[3] is regarded as the first purpose-built automobile. It was made in 1885.

In 1896, John Henry Knight showed a tri-car at The Great Exhibition.^[2]

In 1897, Edward Butler (inventor) made the Butler Petrol Cycle, another three-wheeled car.

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.^[4]

• 1885 Benz Patent Motorwagen

• Goliath pickup truck at a meeting for vintage cars in the Nineties

• Davis D-2 Divan, at the National Automotive and Truck Museum, Auburn, Indiana, United States

• Davis 494, at the National Automotive and Truck Museum, Auburn, Indiana, USA

• Folding City Car: Zaschka Three-wheeled car, 1929. Engelbert Zaschka, German inventor, and his folding three-wheeler.

• Velorex was a manufacturing cooperative in Solnice, Czechoslovakia, formed in 1936 to satisfy demand for small, inexpensive city cars.

• Mazda T2000 truck 1957–1974, length 6.08 m, width 1.84 m, max speed 100 km/h

• An early Daihatsu Midget, which would serve as the basis for auto rickshaws that proliferate across South and Southeast Asia

• 2016 Pembleton Supersports

Configurations

Two front

A configuration of two wheels in the front and one wheel at the back presents two advantages: it has improved aerodynamics, and that it readily enables the use of a small lightweight motorcycle powerplant and rear wheel. This approach was used by the Messerschmitt KR200 and 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 transversal stability (the center of mass is further to the front) and traction (two driven wheels instead of one). Some vehicles have a front engine driving the single rear wheel, similar to the rear engine driving the rear wheel. The wheel must support acceleration loads as well as lateral forces when in a turn, and loss of traction can be a challenge.

A new tadpole configuration has been proposed with a rear engine driving the front wheels. This concept (Dragonfly Three Wheeler^[5]) claims both stability and traction (two driven wheels), as well as a unique driving experience.

With two wheels in the front (the "tadpole" form or "reverse trike") the vehicle is far more stable in braking turns, but remains more prone to overturning in normal turns compared to an equivalent four-wheeled vehicle, unless the center of mass is lower and/or further forward. Motorcycle-derived designs suffer from most of the weight being towards the rear of the vehicle.^{[citation needed]}

For lower wind resistance (which increases fuel efficiency), a teardrop shape is often used.^{[citation needed]} A teardrop is wide and round at the front, tapering 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. Examples include the Aptera 2 Series and Myers Motors NmG.

Two rear

Having one wheel in front and two in the rear for power reduces the cost of the steering mechanism but greatly decreases lateral stability when cornering while braking.

When the single wheel is in the front (the "delta" form, as in a child's pedal tricycle), the vehicle is inherently unstable in a braking turn, as the combined tipping forces at the center of mass from turning and braking can rapidly extend beyond the triangle formed by the contact patches of the wheels. This type, if not tipped, also has a greater tendency to spin out ("swap ends") when handled roughly.^{[citation needed]}

Lateral stability

The disadvantage of a three-wheel configuration is lateral instability—the car will tip over in a turn before it will slide. This can be prevented in three ways:

• by placing the center of mass closer to the ground
• by placing the center of mass closer to the axle with two wheels
• by increasing the track width

In the case of a three-wheeled ATV, tipping may be avoided by the rider leaning into turns.

Tilting option

To improve stability some three-wheelers are designed to tilt while cornering like a motorcyclist would do. The tilt may be controlled manually, mechanically or by computer.

A tilting three-wheeler's body or wheels, or both, tilt in the direction of the turn. Such vehicles can corner safely even with a narrow track.

Some tilting three-wheelers could be considered to be forms of feet forwards motorcycles or cabin motorcycles or both.

Electric

Battery

Three-wheeled battery powered designs include:

• Aptera 2 Series
• Arcimoto
• CityEl
• Commuter Cars Tango
• Cree SAM
• Myers Motors NmG (formerly Corbin Sparrow)
• Toyota i-Road
• Triac
• Vanderhall Edison2
• ZAP Xebra

Solar

The world's fastest solar-powered vehicle, Ashiya University's Sky Ace TIGA, is a three-wheeler. It achieved 91.332 kilometres per hour (56.751 mph) at Shimojishima Airport, in Miyakojima, Okinawa, Japan, to win the Guinness World Record, on 20 August 2014.^[6] It took the record from another three-wheeler, Sunswift IV, designed and built at the University of New South Wales in Australia,^[7] by a margin of almost 3 km/h.

Steam

The world's first full-size self-propelled land vehicle was a three-wheeler. French Army Captain Nicolas-Joseph Cugnot's 1770 fardier à vapeur (steam dray), a steam tricycle with a top speed of around 3 km/h (2 mph), was intended for hauling artillery.^[8]

Another of the earliest preserved examples is the Long steam tricycle, built by George A. Long around 1880 and patented in 1883,^[9][10] now on display at the Smithsonian Institution.

Wind

The Whike is a recumbent tricycle with a sail, made in the Netherlands.

All-terrain vehicles

Due to the incidence of injuries related to their use, a 10-year ban, entirely voluntary for manufacturers, was placed on the sale of new three-wheeled all-terrain vehicles in the United States in January 1988.^{[citation needed]} However, it should be noted that more injuries were sustained by riders by not applying a proper riding technique, and lack of wearing proper safety gear such as helmets and riding boots. In a search conducted by the Consumer Product Safety Commission, it was determined that "no inherent flaw was found in the three wheel design".^{[citation needed]}

Registration

In the U.S, the National Highway Traffic Safety Administration defines and regulates three-wheeled vehicles as motorcycles.^[11] However, in 2015 a bill was introduced in Congress that would prevent some three wheeled vehicles from being classified as motorcycles in the United States, instead creating a new classification for "autocycles".^[12][13]

Driver's license and registration requirements vary on a state-by-state basis. Some states require drivers of three wheeled vehicles to have a motorcycle license and register the vehicle as a motorcycle. Some states, including Virginia, Kansas, and Indiana, classify some three wheeled vehicles as autocycles. Virginia defines an autocycle as "a three-wheeled motor vehicle that has a steering wheel and seating that does not require the operator to straddle or sit astride and is manufactured to comply with federal safety requirements for motorcycles."^[14] Indiana defines it as "a three (3) wheeled motor vehicle in which the operator and passenger ride in a completely or partially enclosed seating area that is equipped with:(1) a rollcage or roll hoops; (2) safety belts for each occupant; and (3) antilock brakes;and is designed to be controlled with a steering wheel and pedals."^[15] In other jurisdictions, such as British Columbia, Canada, and Connecticut, a three-wheeled vehicle with an enclosed passenger compartment or partially enclosed seat is considered an automobile.^{[citation needed]}

Examples

Two front wheels

Two rear wheels

• Complete A-Z list of three-wheelers since 1940