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A 'tricycle' (often abbreviated to 'trike') is a three-wheeled vehicle.
Tricycles generally follow one of 'three layouts':

★ 'delta', with two wheels at the back and one at the front. One or both rear wheels can be driven, while the front is used for steering (the usual layout), or rear wheels can steer while the front wheel is driven, or any combination of both; and

★ 'tadpole', with two steered wheels at the front and one driven wheel at the back (the usual layout). The front wheels can also be driven while the rear wheel steers, or all three wheels can be powered with the front wheels also performing the steering.

★ 'iL3', an in line three wheeled vehicle, with two steered wheels: one at the front and the other in the middle or at the rear. When the mid wheel is steered, the wheel is turned by a mechanism in the same direction to the front wheel. When the rear wheel is steered, the wheel is turned by a mechanism in the opposite direction to the front wheel (countersteer).
Not all trikes fall into one of these three classes. For example, some early pedal tricycles used two wheels in tandem on one side and a larger driving wheel on the other.
It is common, but not universal, for tricycles to have front and rear 'wheels' of different 'sizes'.

Contents

History

Pedal tricycles

Special purposes

Tandem and hand trikes

Freight trikes

Trike rickshaws

Other

Motorized tricycles

See also

External links

History

The word ''tricycle'' has been in use since the early 19th century and stems from the Greek ''tri'' (''treia''), meaning three, and ''kyklos'', meaning a circle or wheel. [1] The first recorded usage is apparently in 1828, signifying a "three-wheeled horse-drawn carriage." Tricycles have evolved to include various forms of propulsion including pedals, steam and internal combustion engines. The abbreviation ''trike'' has been in use since 1883.
The most common type of tricycle today is the child's toy pedal tricycle, but advanced forms exist. Early tricycles were mostly for adults. Adult pedal tricycles are known to have existed from 1868.

Pedal tricycles

These may be upright or (increasingly) recumbent. Upright tricycles are often favoured by those with mobility problems. Recumbent tricycles are particularly suitable for long-distance use, including cycle touring and Audax riding. Upright trikes are usually deltas, although the Newton tadpole upright conversion is well regarded. Either type can be made low and large enough to be difficult to overturn on dry pavement, but usually the centre of gravity is high enough that tipping is possible, especially if the rider does not lean into the corners.
Adults may find upright tricycles difficult to ride due to familiarity with the counter-steering required to balance a bicycle. The variation in the camber of the road is the principal difficulty to be overcome once basic tricycle handling is mastered. Recumbent trikes are less affected by camber and, depending on track width and riding position, capable of very fast cornering. A few trikes are designed to tilt into the corners much as a bicycle does, and this also renders them more comfortable on cambered roads. They are discussed as tilting three wheelers (TTW's).
In the case of delta tricycles, the drive is often to just one of the rear wheels, though in some cases both wheels are driven through a differential. A double freewheel, preferably using no-backlash roller clutches, is considered superior. A jackshaft drive permits either single or two-wheel drive. Tadpoles are generally rear wheel drive.
Recumbent tadpole trikes often brake one wheel with each hand, allowing the rider to brake one side. This has led to a geometry (misnamed centre point steering) with a kingpin axis intersecting the ground directly ahead of the tyre contact point, producing a normal amount of trail. This arrangement, elsewhere called "zero scrub radius" is used to mitigate the effects of one-sided braking on steering. It is said to allow the rider to steer by braking. Zero scrub is generally avoided on the grounds that it reduces steering feel and increases wandering. The alternative is to use standard Ackermann steering geometry, perhaps with both front brakes operated by the stronger hand. The KMX Kart stunt trike makes a feature of allowing the rear brake to be operated separately, allowing "handbrake turns".
In the UK, upright tricycles are sometimes referred to as "barrows". Many trike enthusiasts ("trikies") in the UK belong to the Tricycle Association, formed in 1929. They engage in its day rides, tours and time trials. Massed start racing of upright tricycles is limited to one or two criteria such as in Bungay, Suffolk each year.
Makers of upright trikes include George Longstaff, Higgins, and Pashley Cycles in the UK. Makers of recumbent trikes include Hase (who make the largest-selling delta, the Kettwiesel, improbably named after the British children's programme Catweazle); Inspired Cycle Engineering, who make the Trice range of tadpole trikes; AVD, who build the Burrows Windcheetah or ''Speedy''; Australia's Greenspeed;, Big Cat HPV which builds the 6 Catrike models in Florida, and Stein, a recent entrant from North Serbian province of Vojvodina in South-Eastern Europe.
The tadpole trike, while gaining popularity, is still mainly used by middle-aged former bicyclists who are tired of developing back pains and associated pains from normal upright bikes ("wedgies", as they are called in many recumbent forums). Many trikes are homebuilt as trikes are still fairly expensive, due to the use of high quality components (for reasons including the fact that a trike becomes perceptibly heavier than a two-wheeler anyway) and small order numbers. Most good adult trikes cost at least $US2000 - so homebuilders can manufacture their own frames and buy or use cheap 26" wheels instead of the expensive 20" wheels on most commercial trikes.

Special purposes

Some tricycles (e.g. the Christiania and the Pashley load trike) are designed for load carrying. Others are designed for racing or for comfort. Some recumbent tricycles are fully enclosed for all weather use as well as aerodynamic benefits; these are known as velomobiles.

Tandem and hand trikes

Tandem trikes are also made by companies like Greenspeed and Inspired Cycle Engineering (ICE). They allow two people to ride in a recumbent position back to back with an extra-strong backbone frame to hold the extra weight. Hand-crank trikes are also made by companies like Greenspeed and they allow the arms to operate a crank, either as a sole source of power or a double drive with footpower.

Freight trikes

Urban delivery trikes - see articles "workbike" and "freight bicycle" - are in most countries most often of the tadpole configuration, with the cargo box (platform, etc.) mounted between the front wheels. India and China, however, are two significant strongholds of the rear-loading "delta" carrier trike.

Trike rickshaws

Most cycle rickshaws, used for carrying passengers for hire, are tricycles. These vehicles are widely used in South and Southeast Asia, but have become popular in UK, Europe and USA as an advertising media in larger cities.

Other

Spidertrike is a unique design of recumbent pedicab that features exclusively in central London and is operated by Chariot Bikes. It is a front wheel driven tricycle, that is articulated behind the driver seat. These pedicabs have advanced features like double disc, hydraulic disc brakes and hub gears.

Motorized tricycles

Similar to motorcycles, some tricycles are motorized. Some of the earliest prototype automobiles were steam tricycles. However, motorcycles with sidecars are not considered tricycles, nor are the three wheeled automobiles such as the Morgan).
A motorized tricycle's wheels may be arranged in either configuration: delta or tadpole. A delta trike has one wheel in front and two in back, and the tadpole trike has two wheels in front and one in back. Occasionally, rear wheel steering is used, although this increases the turning circle and can affect handling (the geometry is similar to a regular trike operating in reverse, but with a steering damper added). Thrust SSC used a rear-steer tadpole layout (technically, Thrust SSC was not a tricycle; it had four wheels, two at each end. The rear steering wheels (2) were mounted very close together).

Tadpoles are more stable under braking and more likely to slide instead of roll; front braking hard on a delta requires the vehicle to steer almost straight to avoid tipping. The balance of friction patches and rolling resistance also means that tadpoles tend to understeer and deltas oversteer.
Motor trikes are attractive for those with mobility or balance problems, for carrying multiple passengers on a motorcycle licence, or to avoid helmet use regulations. These machines are generally custom-built and often finished to a very high standard. A common arrangement is to fit chopper-style ("ape hanger") front forks to a VW Beetle engine and transaxle, popular because it is largely self-contained on a single subframe.
Mass-manufactured motor tricycles include the Piaggio Ape (''Bee'') delivery trike; the T-Rex reverse trike; trikes used by municipal authorities in the USA; and, historically, vehicles such as the Scammell Scarab railway dray, a common sight around post-war British railway stations. The Piaggio MP3 reverse trike leans like a 2-wheeled bike, with the front wheels moving independently in a scissors action.

See also

★ Bicycle

★ Bicycle trailer

★ Cycle rickshaw

★ Freight bicycle

★

★ Handcycles

★ History of the bicycle

★ Human-powered transport

★ Mini 500

★ Quadricycle

★ Recumbent bicycle

★ Steam tricycle

★ Tandem bicycle

★ Trailer bike

★ Trikke

★ Three wheeled cars

★ Three wheeler

★ Utility cycling

★ Velocipede

★ Velomobile

★ Workbike

External links

★ 1911 Britannica article

★ Antique and vintage tricycle information, history and identification.