A tricycle (often abbreviated to trike) is a three-wheeled vehicle. While tricycles are often associated with the small three-wheeled vehicles used by pre-school age children, they are also used by adults for a variety of purposes. In theUnited States and Canada, adult-sized tricycles are used primarily by older persons for recreation, shopping, and exercise. In Asia and Africa, tricycles are used primarily for commercial transportation, either of passengers in pedicabs, or of freight and deliveries.

Human-powered trikes are usually powered by pedals, although some models have hand cranks. Motorized trikes can be powered with a variety of methods, including motorcycle engines, smaller automatic transmission scooter motors, and electric motors. The term "tricycle" may or may not include motorized Three Wheeled Cars, depending on local laws.

Design

Layouts

Tricycles generally follow one of three layouts:

• Upright, Resembling a two wheeler (diamond frame (traditionally) or open) but with two wheels at the back and the rider straddling the frame. Steering is through a handlebar directly connected to the front wheel like a bicycle;

• Delta, is similar to an upright, with two wheels at the back and one at the front, but has a recumbent layout in which the rider is seated in a chair-like seat. One or both rear wheels can be driven, while the front is used for steering (the usual layout). Steering is either through a linkage, with the handlebars under the seat (USS) or directly to the front wheel with a large handlebar (OSS); and

• Tadpole (or reverse trike), a recumbent design with two steered wheels at the front and one driven wheel at the back (though one model has the front wheels driven while the rear wheel steers). Steering is either through a single handlebar linked with tie rods to the front wheels' stub axle assemblies (Indirect) or with two handlebars (rather, two half-handlebars) each bolted to a steerer tube, usually through a bicycle-type headset and connected to a stub axle assembly (Direct). A single tie rod connects the left and right axle assemblies.

The tadpole trike, which is rapidly becoming the most popular design, is often used by middle-aged or retiree-age former bicyclists who are tired of the associated pains from normal upright bikes. With its extremely low center of gravity, aerodynamic layout and light weight (for trikes), tadpoles are considered the highest performance trikes.

Not all trikes fall into one of these three classes. For example, some early pedal tricycles from the late 1800s used two wheels in tandem on one side and a larger driving wheel on the other. Another design is an in line three wheeled vehicle, with two steered wheels: one at the front and the other in the middle or at the rear. It is not unusual for tricycles to have front and rear wheels of different sizes.

• Tricycle Conversion set A complete unit for bolting onto a (usually) adult bicycle to form a delta or tadpole upright tricycle. Manufacturers have included Rogers, Higgins, Longstaff and Trykit.(Deltas) The last two are still active in supplying conversion axle sets and hand built, complete tricycles and tandem tricycles to order. Newton (Roman Road) provide a unique, upright, tadpole, tricycle conversion set with Ackerman steering and front hub or disk brakes. As well as building complete tadpole, upright trikes and tandems to order. The advantages of a trike conversion set include lower cost compared with hand built tricycles and the freedom to choose almost any donor bicycle frame. Tricycle conversion sets tend to be heavier than a high quality, hand built, sports, touring or racing tricycle. Conversion sets can give the would-be serious tricyclist a taste of triking before making the final decision to purchase a complete tricycle. (or tricycle frameset) Conversion sets can also supplied ready to be brazed onto a lightweight, steel, bicycle frame to form a complete trike.

Adult and child model comparison

Another way of categorizing tricycles is by whether they are designed for children or adults. Children's tricycles and most adult tricycles made for the recreational market use the upright layout. From a design point of view, the difference between children's and adult tricycles is that whereas children's tricycles are usually direct-drive and have no brakes, adult trikes usually have a gear-drive with multiple speeds and front and rear brakes.

Tricycles are typically used by children between the ages of two and four, after which point they usually switch to a bicycle, often with training wheels. Parents choosing a tricycle for their child should ensure that the trike is not too tall and that the seat is too high, and that the wheelbase is wide enough, because if this is the case, the child may tip over easily. The seat should be stable, which is not always the case with the most inexpensive models. Some trikes have back rests which provide support and a push bar for parents so that the parents can push the child up hills or hold the child back when descending, or in case of the sudden approach of other traffic. For safety, children should wear a helmet when riding their trike; some parents may also attach a safety flag to the trike so that the child will be more visible to drivers.

Children's trikes are made of steel frames or plastic. One disadvantage of plastic frames is that they be more likely to tip over than a steel frame if a heavier child is riding. On the plus side, plastic frames will not rust like steel frames if the trike is left out in the rain. A good quality trike's wheels will have treads, which provide better traction.

While most children's trike have direct drive, a small number of models such as the Cheetah have chain drive. Unlike adult bikes, children's trikes do not always have inflatable wheels; instead, some trikes have solid rubber wheels. While this adds to the weight of the tricycle and reduces the shock-absorbing qualities, it eliminates issues with flat tires, punctures, and leaky tubes. Since most trikes are direct drive, the child can slow the trike down by resisting the forward motion of the pedals, as with an adult fixed gear bike. Pull brakes are rarely used on kid's trikes, but some "Bigwheel"-style plastic trikes have lever brakes in which an inverted half-moon-shaped brake pad is pressed against the driving surface of the righ rear wheel.

Riding

Adults may find upright tricycles difficult to ride because of familiarity with the counter-steering required to balance a bicycle, in which the weight of the body is used during turns. 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 referred to 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 generally use a bicycle's rear wheel drive and for that reason are usually lighter, cheaper and easier to replace and repair.

Braking

Typical upright trikes for adults have front and rear brakes. The front brakes are usually "pull brakes" or V-brakes, and the rear brakes can be pull brakes or internal drum brakes (which operate like automobile drum brakes).

Recumbent trikes often brake one wheel with each hand, allowing the rider to brake one side alone to pull the trike in that direction. This has led to a geometry (also called centre point steering) with the 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. While zero scrub can reduce steering feel and increase wandering it can also protect novices from spinning out and/or flipping.

The alternative is to use standard Ackermann steering geometry, perhaps with both front brakes operated by the stronger hand. While the KMX Kart stunt trike with this setup allows the rear brake to be operated separately, letting the rider do "bootlegger turns", the standard setup for most trikes has brakes for each side operated by each hand.

Strengths and weaknesses

Trikes' strongest suits are cornering, stability, comfort, rider stamina and terminal velocity. Trikes can be used by adults who have problems riding bicyles. As well, trikes are a good choice for elderly riders who are worried about falls. Trikes can ride and climb at very low speed and a kickstand is never needed.

Trikes are always heavier than bikes of the same quality. In fact, the lightest commercially-made tadpole trikes, at around 30 pounds, are easily twice the weight of an upright bicycle of the same cost and quality. Deltas are even heavier. Shortcomings that potential tadpole trikers should realize center on the low riding position which makes them difficult to mount (grab handles are often available) and makes them hard to see in traffic, so flags and blinking lights are often used. Visibility concerns become minimal on bike trails and off-street riding.

An often-noted problem with recumbent trikes, much debated by trikers and recumbent riders of all kinds, is their poor climbing ability: the rider cannot get out of the saddle and stand up on the pedals to climb hills. Trikers argue that they make up the time lost going up hills by going much faster on the downhill side because of the low, aerodynamic riding position.

Special purposes

Some tricycles (such as 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. Some tricycles, such as the Zigo Leader, are designed to transport children.

Hand and foot trike

With hand and foot trikes, the rider makes a pair of front wheels change directions by shifting the centre of weight and moves forward by rotating the rear wheel. The hand & foot trike can be also converted into a manual tricycle designed to be driven with both hands and both feet. There are also new hybrids between a handcycle, a recumbent bike and a tricycle, these bikes make it even possible to cycle with legs despite a spinal cord injury.

Tandem and hand trikes

Recumbent tandem trikes allow two people to ride in a recumbent position with an extra-strong backbone frame to hold the extra weight. Some allow the "captain" (the rider who steers) and "stoker" (the rider who only pedals) to pedal at different speeds. They are often made with couplers so the frames can be broken down into pieces for easier transport. Manufacturers of recumbent trikes include Greenspeed, WhizWheelz and Inspired Cycle Engineering (ICE).

Hand-crank trikes use a hand-operated crank, either as a sole source of power or a double drive with footpower from pedals and hand-power from the hand crank. The hand-power only trikes can be used by individuals who do not have the use of their legs due to a disability or an injury. They are made by companies including Greenspeed, Invacare, Quickie and Druzin.

Freight trikes

Urban delivery trikes are designed and constructed for transporting large loads. These trikes include a cargo area consisting of a steel tube carrier, an open or enclosed box, a flat platform, or a large, heavy-duty wire basket. These are usually mounted over one or both wheels, low behind the front wheel, or between parallel wheels at either the front or rear of the vehicle, to keep the center of gravity low. The frame and drivetrain must be constructed to handle loads several times that of an ordinary bicycle; as such, extra low gears may may added. Other specific design considerations include operator visibility and load suspension. Many, but not all, cycles used for the purpose of vending goods such as ice cream cart trikes or hot dog vending trikes are cargo bicycles.

Freight trikes are most often of the tadpole configuration, with the cargo box (platform, etc.) mounted between the front wheels. India and China are significant strongholds of the rear-loading "delta" carrier trike. Freight trikes are also designed for indoor use in large warehouses or industrial plants. The advantage of using freight trikes rather than a motor vehicle is that there is no exhaust, which means that the trike can be used inside warehouses. While another option is electric golf cart-style vehicles, freight trikes are human-powered, so they do not have the maintenance required to keep batteries on golf carts charged up. For more information, see the articles on "workbike" and "freight bicycle".

Common uses include:

• delivery services in dense urban environments
• food vending in high foot traffic areas (including specialist ice cream bikes)
• transporting trade tools, including around large installations such as power stations and CERN
• airport cargo handling
• recycling collections
• warehouse inventory transportation
• mail (The UK post office operates a fleet of 33,000 bicycles, mainly the Pashley MailStar)
• Food collection,
• Child transport; it is estimated that 90% of the freight bicycles sold in Amsterdam are used primarily to carry children.

Trike rickshaws

Most cycle rickshaws, used for carrying passengers for hire, are tricycles with one steering wheel in the front and two wheels in the back supporting a seating area for one or two passengers. Cycle rickshaws often have a parasol or canopy to protect the passengers from sun and rain. These vehicles are widely used in South Asia and Southeast Asia, where rickshaw driving provides essential employment for recent immigrants from rural areas, generally impoverished men. In the 1990s and 2000s, rickshaws have become increasingly popular in big cities in the UK, Europe and US, where they provide urban transportation, novelty rides, and serve as an advertising media.

Spidertrike is a recumbent cycle rickshaw that is used in central London and is operated by Eco Chariots. It is a front wheel drive tricycle, articulated behind the driver seat. The passenger is protected from rain and sun with a canopy. These pedicabs have features like double disc, hydraulic disc brakes and internal hub gears.

Manufacturers

Makers of upright trikes include George Longstaff, Higgins, and Pashley Cycles in the UK. Italian company Di Blasi make a folding upright trike, which folds to a compact 68 x 28 x 62.5 cm. There are also many inexpensive, mass-produced upright trikes available through mass-market retailers. They are generally heavy and of uneven quality, but are suitable for occasional, low-demand riding, especially by those with mobility problems.

Makers of recumbent trikes include KMX; Hase (who make the Kettwiesel delta, improbably named after the British children's programme Catweazle); Inspired Cycle Engineering, who make the Trice range of tadpole trikes; AVD, who build the record holding Burrows Windcheetah or Speedy, a design exhibited in the Metropolitan Museum of Modern Art (MoMA); Australia's Greenspeed, one of the oldest manufacturers; Michigan-based WhizWheelz, which makes 10 models, including a sub-US$1000 model tadpole and a tandem; Big Cat HPV which builds the 8 Catrike models in Florida and Sidewinder Cycle which has a front wheel drive system with rear wheel steering builds 3 models all with Electric assist capability located in California.

The largest manufacturer of recumbent trikes is Sun Bicycles who make both tadpole and delta trikes. The deltas are built from designs licensed from Gardner Martin's EasyRacers, the premiere maker of recumbent bicycles. Sun bicycles are factory-made in Taiwan and are among the least expensive trikes of good quality.

The least expensive adult trikes are steel framed upright models; the most basic models suitable for leisure riding or shopping start at about $300, and mass-market models tend to be in the $500 to $700 USD range. Mid-range trikes with better quality parts and more features are in the $1000 to $1600 range. High-end adult trikes begin at about $2000 USD, with some models costing over $3500 USD.

History

The first tricycle was built in 1680 by a disabled German man who wanted to be able to maintain his mobility. Since he was a watch-maker, he was able to create a tricyle that was powered by hand cranks. In 1789, two French inventors, Blanchard and Maguier developed a tricycle. The Journal de Paris, noting that the new invention was different from the existing two-wheeled bicyle, invented the term "tricycle" to differentiate between the two human-powered vehicles.



In 1818, British inventor Denis Johnson patented his approach to designing tricycles. In 1876, James Starley developed the Coventry Lever Tricycle, which used two small wheels on the right side and a large drive wheel on the left side; power was supplied by hand levers. In 1877, Starley developed a new vehicle he called the Coventry Rotary, which was "one of the first rotary chain drive tricycles." Starley's inventions started a tricycling craze in Britain; by 1879, there were " twenty types of tricycles and multi-wheel cycles ... produced in Coventry, England, and by 1884, there were over 120 different models produced by 20 manufacturers."

Tricycles were used by riders who did not feel comfortable on the high wheelers, such as women who wore long, flowing dresses. 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 participate in day rides, tours and time trials. Massed start racing of upright tricycles is limited to one or two criteriums such as in Bungay, Suffolk each year.

Motorized tricycles

Some tricycles are powered with motors, typically gasoline engines. Depending on the design of the vehicle, motorized trikes may be categorized as motorcycles or motor scooter. The main difference between a motorcyle trike and a scooter trike is that motorcycles are sat on in a "saddle"-style seating (as with a horse), with the legs apart, and motorcyles have manual transmissions. Scooters have a "step-through" seating style, in which the driver sits on a more chair-like seat, with the legs together; as well, scooters have automatic transmissions. While laypersons often associate the engine size as a dividing line between motorcyles and scooters, since a typical scooter has a small 50 cc engine, engine size is not one of the dividing lines, because some scooters such as the Bergmann have 600 cc engines.

Motorcycles with sidecars are not usually considered tricycles. It can be harder to categorize three wheeled automobiles. While some early prototype automobiles were steam tricycles, 1930s and 1940s-era three-wheeled cars such as Morgan Motor Company cars are often classified as cars rather than motorcycles.

Motorcyle tricycles

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. Similarly, the engine, transmission and rear wheel may be taken from a large motorcycle as a single unit, and used in the construction of a tadpole trike.

Mass-manufactured motor tricycles include the Piaggio Ape (Bee) delivery trike (delta); the Bombardier Recreational Products Can-Am Spyder (tadpole); 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.

Motorized freight trikes

In Asian and Southeast Asian countries, motorized trikes are used as small freight trucks and commercial vehicles. Nicknamed "three-wheelers" or "tuk-tuks" in popular parlance, they are a motorized version of the traditional rickshaw or velotaxi. They have a small three-wheeled cart driven by a person, and is related to the cabin cycle.While they are mostly used as taxis for hire, they are also used for commercial and freight deliveries. They are particularly popular where traffic congestion is a problem in cities like Bangkok, Dhaka, Ahmedabad, Pune, Delhi, Mumbai, Chennai, Hyderabad and Bengaluru,

They usually have a sheet-metal body or open frame that rests on three wheels, a canvas roof with drop-down sides, a small cabin in the front of the vehicle for the driver, an air-cooled scooter version of a two-stroke engine, with handlebar controls instead of a steering wheel.The smaller motorized trikes are used as delivery vehicles for lighter loads. The larger trikes, with more powerful engines, have larger cargo bays, and they can carry freight within a city.

Motorized scooter trikes

Scooter are motor vehicles that can vary significantly in design and capability, but are generally derived from a traditional design combining a step-through frame with front fairings and floor boards, inner fairing storage, small wheels (10" to 16" in diameter), and a rear swingarm-mounted engine suitable for light duty. The classic scooter design features a step-through frame and a flat floorboard for the rider's feet. Most newer scooters use a continuously variable transmission (CVT). While most scooters have two wheels, some scooters are three-wheeled scooter trikes.

Most scooter trikes have two rear wheels which are the drive wheels and a front wheel which is used for steering. Some 2000s-era scooter trikes such as the Piaggio MP3 are reverse trikes, with two wheels in front and one in the back. The MP3 leans like a 2-wheeled bike, with the front wheels moving independently in a scissors action.

See also

• Bicycle
• Cycle rickshaw
• Freight bicycle
• Sidecar
• Tandem bicycle
• Three wheeled cars
• Three wheeler
• Unicycle
• Zigo

References

External links

• Recumbent Trike Manufacturers
• Pedicab.com Largest US Pedicab and Rickshaw manufacturer.
• 1911 Britannica article
• Antique and vintage tricycle information, history and identification.