AskDefine | Define tricycle

Dictionary Definition

tricycle n : a vehicle with three wheels that is moved by foot pedals [syn: trike, velocipede]

User Contributed Dictionary

English

Pronunciation

tri·cy·cle

Etymology

tri- + cycle

Noun

  1. A cycle with three wheels, powered by pedals and usually intended for young children.

Translations

French

Noun

tricycle m
  1. tricycle

Extensive Definition

A tricycle (often abbreviated to trike) is a three-wheeled vehicle.
Tricycles generally follow one of three layouts:
  • upright, Resembling a two wheeler (diamond frame) but with two wheels at the back and the rider stradling 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. 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, a recumbent design with two steered wheels at the front and one driven wheel at the back. Rarely, the front wheels can be driven while the rear wheel steers. Steering is either through a linkage and a tie rod to the plates of the spindle assemblies (USS) or with two handlebars, each connected to a steerer tube (usually through a bicycle headset, with the handlebars acting as stems) and a tie rod between the plates of the spindle assemblies (OSS).
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. 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.
Adults may find upright tricycles difficult to ride because of 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 generally use a bicycle's rear wheel drive and for that reason are usually lighter, cheaper and easier to replace and repair.
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.
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 criteria such as in Bungay, Suffolk each year.
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 perfectly 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; and Big Cat HPV which builds the 6 Catrike models in Florida. 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.
In the past trikes have been associated with homebuilders as manufactured trikes are extremely expensive due to the small order numbers and the high quality of hand-built construction. Most good quality adult trikes cost at least $US2000 and the best can easily exceed $US3500 (though several moderate quality trikes in the $US999 to $US1600 range have been introduced recently).
The tadpole trike, which is rapidly becoming the most popular design, is often used by middle-aged former bicyclists who are tired of the associated pains from normal upright bikes ("wedgies" or "DFs" [diamond frames], as they are called in many recumbent forums). With its extremely low center of gravity, aerodynamic layout and light weight (for trikes), tadpoles are considered the highest performance trikes.
An often-noted problem with recumbent trikes, much debated by trikers and recumbent riders of all kinds, is their poor climbing ability: the rider can't 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. In fact tadpole trikes hold most of the current human powered vehicle speed records. More germane to trikes climbing ability is their weight: 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.
Trikes strongest suits are cornering, stability, comfort, rider stamina and terminal velocity. They also have some not so obvious benefits: the rider doesn't need to uncleat at stops (which also makes for quicker getaways), the ability to ride and climb at very low speed and the upright position giving a much more pleasant view of the world around. 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.

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.

Tandem and hand trikes

Tandem trikes are also made by companies like Greenspeed, WhizWheelz and Inspired Cycle Engineering (ICE). They allow two people to ride in a recumbent position with an extra-strong backbone frame to hold the extra weight. Some allow the captain and stoker to pedal at different speeds. They are often made with couplers so the frames can be broken down for easier transport. Hand-crank trikes are also made by companies like Greenspeed, Invacare, Quickie and Druzin 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 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.

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 recumbent pedicab that features exclusively in central London and is operated by Chariot Bikes. It is a front wheel driven tricycle, 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. 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; Bombardier Recreational Products Can-Am Spyder; 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.

E-tricycle

On January 19, 2007, Puerto Princesa Mayor Edward S. Hagedorn unveiled the environment-friendly and economical electric-powered “Trikebayan” (which does not emit any noise or carbon monoxide) at the Kapihan sa Sulo forum, Sulo Hotel, Quezon City. The Trikebayan costs only P 48 or $ 1.20 per day to operate, while a gasoline-powered tricycle operation would cost P 200. Rolly Concepcion, who conceptualized the Trikebayan, said that converting a tricycle engine to electric costs P 68,000. The 36-watt rechargeable battery under the passenger seat can run for 12 hours.
tricycle in German: Dreirad
tricycle in Persian: سه‌چرخه
tricycle in French: Tricycle
tricycle in French: Trike
tricycle in Japanese: トライク
tricycle in Japanese: 三輪車
tricycle in Dutch: Tricycle
tricycle in Polish: trajka
tricycle in Swedish: Trehjuling
tricycle in Walloon: velo ås troes rowes
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