From Wikipedia, the free encyclopedia
Kart racing or Karting is a variant of open-wheeler motor sport with simple, small four-wheeled vehicles called karts, go-karts, or gearbox/shifter karts depending on the design. They are usually raced on scaled-down circuits. Karting is commonly perceived as the stepping stone to the higher and more expensive ranks of motorsports.
Art Ingels is generally accepted to be the father of karting. A veteran hot rodder and a race car builder at Kurtis Kraft, he built the first kart in Southern California in 1956. Karting has rapidly spread to other countries, it currently has a large following in Europe.
Karts vary in speed and some (Superkart) can reach speeds exceding 160 mph (250 km/h). A Formula A kart, with a 100 cc 2 stroke engine and an overall weight including the driver of 150 kilograms, can accelerate from 0-60 mph in under 4.5 seconds, and has a top speed of 85 mph (140 km/h). It takes a little more than 3 seconds to go from 0 to 60 mph with a 125 cc shifter kart (6 gears), with a top speed of 115 mph (185 km/h) on long circuits.
The chassis are made of steel tube. There is no suspension therefore chassis have to be flexible enough to work as a suspension and stern enough not to break or give way on a turn. Kart chassis are classified in the USA as 'Open', 'Caged', 'Straight' or 'Offset'. All CIK-FIA approved chassis are 'Straight' and 'Open'.
- Open karts have no roll cage.
- Caged karts have a roll cage surrounding the driver, they are mostly used on dirt tracks.
- In Straight chassis the driver sits in the center. Straight chassis are used for sprint racing.
- In Offset chassis the driver sits on the left side. Offset chassis are used for left-turn-only speedway racing.
The stiffness of the chassis enables different handling characteristics for different circumstances. Typically, for dry conditions a stiffer chassis is preferable, while in wet or other poor traction conditions, a more flexible chassis may work better. Best chassis allow for stiffening bars to be added or removed according to race conditions.
Braking is achieved by a disc brake mounted on the rear axle. Front disc brakes are increasingly popular.
Professionally raced karts typically weigh 165 to 175 lb (75 to 80 kg), complete without driver. Avanti Kart, Tony Kart, Top Kart, Birel, CRG and Mach 1 Kart are a few well known examples of the many European manufacturers of race-quality chassis. American companies in the shifter kart market include: GT Race Karts, Trackmagic and Margay (see list of karting manufacturers).
Racing karts use small 2-stroke or 4-stroke engines.
- 2-stroke engines were originally taken from motorcycles, but have become a kart-specialised item with dedicated manufacturers. IAME (Parilla, Komet), TM, Vortex, Yamaha and Rotax are manufacturers of such engines. These can develop from about 16 hp to 32 hp for a single-cylinder 100 cc unit to 90 hp for a twin 250 cc. The most popular categories worldwide are those using 100 cc engines and the "Touch-and-Go" 125 cc units. 100 cc 2-stroke kart engines can run at 19,000 rpm. Most are water-cooled.
- 4-stroke engines can be standard air-cooled lawn mower engines, sometimes with small modifications, developing from about 5 to 20 hp. Briggs & Stratton, Tecumseh, Kohler, Robin, and Honda are manufacturers of such engines. They are plenty adequate for racing and fun kart applications. There are also more powerful Four-stroke options available TKM, Biland, offering from 15 up to 30 hp, run to and around 11,000 rpm, and are manufactured specifically for karting and are used in some National Championship classes like the Two-strokes.
Listen to 2-stroke kart engines - recorded at the 2006 World Championship in Angerville - France
Karts do not have a differential. The lack of a differential means that one rear tyre must slide while cornering, this is achieved by designing the chassis so that the inside rear tyre lifts up slightly when the kart turns the corner. This allows the tyre to lose some of its grip and slide or lift off the ground completely, depending on the corner, chassis setup or driving style.
Torque is transmitted from the engine to the rear axle by way of a chain. Both engine and axle sprockets are removable, their ratio has to be adapted according to track configuration in order to get the most of the engine.
In the early days karts were direct drive only, but the inconvenience of that setup soon led to the centrifugal clutch for the club level classes. Dry centrifugal clutches are now used in many categories (Rotax Max is one example) and will soon become the norm as the top international classes will be switching to 125 cc clutched engines in January 2007.
Many kart racers in the USA prefer shifter karts, which have a six-speed manual transmission and a clutch to make better use of the more powerful engine. Some of these gearboxes are operated with wheel-mounted paddles. In Europe, competitive kart racers tend to prefer fixed gear 100 cc or 125 cc machines although shifters of 125 cc, 250 cc and occasionally 210 cc are also raced.
Wheels and tires are much smaller than those used on a normal car. Wheels are made of magnesium alloy or aluminum. Similar to other motorsports, kart tyres have different types for use appropriate to track conditions:
- Slicks for dry weather. In international level racing these are some of the softest and most advanced tires in motorsport.
- Rain tires for wet weather
- Intermediates for damp or low traction conditions. Sometimes worn wet tire can be used.
- Special, such as spiked tire for icy conditions, or cuts for high grip dirt/clay speedways. Cuts are modified slicks using a lathe to optimize handling while spiked tyres are slicks with screws through them.
Tires are sometimes prepared with special solvents to soften them and increase grip, however this is banned by many racing organizations. These solvents typically affect the behavior of the tire temporarily and are most often destructive to the rubber. The tire can support acceleration round corners at 2 G (20 m/s²), depending on chassis, engine, and motor setup.
Kart racing is generally accepted as the most economic form of motorsport available. As a free-time activity, it can be performed by almost anybody, and as a motorsport in itself, it is one of the sports regulated by FIA (under the guise of CIK), permitting licensed racing for anyone from the age of 8 onward. In the USA there is not as much FIA involvement, instead the IKF (International Kart Federation) and WKA (World Karting Association) regulate racing.
A variety of kart circuits permit the sport to be practised, although only homologated ones can have official races.
Typically, race formats are one of the following:
Sprint racing takes place on dedicated kart circuits resembling small road courses, with left and right turns. Tracks go from 1/4 mile (400 m) to 7/8 mile (1,500 meters) in length.
The sprint format is a series of short-duration races, normally for a small number of laps, that qualify for a final, with a variety of point scoring calculations to determine the event's overall winner. Typical duration does not normally exceed 15 minutes. Here, speed and successful passing is of the most importance. It normally occurs in the format of three qualifying heats and a final race for trophy positions.
The FIA championships, including the Karting World Championship, take place in this format.
Endurance races last for an extended period, from 30 minutes up to 24 hours or more, for one or more drivers. In general, consistency, reliability, and pit strategy is of greater importance than all out speed.
Speedway racing takes place on asphalt or clay oval tracks which are normally between 1/6 mile and 1/4 mile long. Tracks primarily consist of two straight and four left-turn corners, few tracks are symmetric and oftentimes the shape parallels that of an egg or a tri-oval.
'Offset' kart chassis have been developed for precise handling and adjustability in left-turn-only racing competition taking place on oval and tri-oval tracks.
Speedway kart races range in length from 4 laps for a trophy dash, to 20 laps for a main event.
The two chief racing formats used in dirt speedway karting are heat races and timed laps qualification :
- The International Kart Federation (IKF) runs a racing format of two 10 laps heats followed by a 20 laps final. Finishing positions in the two heat races are used to calculate the starting position in the feature race.
- The World Karting Association (WKA) uses time qualifying. Karts equipped with transponders are sent out onto the track in groups of 5 or less to try to achieve the fastest lap time. Positions for the 20 laps feature event are determined by qualifying time.
Racing classes start at age 7 or 8 and generally run in 3-year age groupings or weight divisions until “senior” status is reached at age 15 or 16, depending on the series.
There are many different classes or formulae in karting. The FIA sanctions international championships in JICA, Intercontinental A, Formula A, Intercontinental C, Super ICC and Superkart Division 1 and Division 2. These are regarded as the top levels of karting and are also raced in national championships. The World Championship is also decided here. The current 2006 World Champion is Davide Fore from Italy.
FIA regulations changes for 2007:
The future CIK-FIA kart categories will be known as KF1, KF2, KF3, KF4 and KZ1, KZ2.
- KF1 will replace the current FA category (Formula A), KF2 will replace the current ICA (Intercontinental A), KF3 will replace the current ICA-Junior (ICA-J or JICA), and KF4 will be the so-called “basic” category. All will be using water-cooled 125 cc “long life” two-stroke engines with starter and clutch, each with different technical specifications (mufflers, air boxes, carburetor, rev limit etc...).
- Super-ICC and ICC (Intercontinental C), which are the 125 cc gearbox categories, the technical regulations of which will undergo no major modifications, will be respectively renamed KZ1 and KZ2.
The most celebrated karting series in the UK is the National karting series, also known as Super 1. There are 3 types of Super 1 championships:
- MSA series : Formula A, ICA, Junior ICA, Formula 100 and Formula Cadet
- Rotax series : Minimax, Junior Max, Senior Max and Senior Max 177
- TKM series : Formula Junior TKM, Formula Junior Intermediate, Formula TKM Extreme, TKM Junior and Senior 4-stroke and since 2006, Honda Cadet
In the United States, the biggest proportion of racers are in the dirt oval classes which often use Briggs & Stratton industrial engines.
In Australia, classes include Midget, Rookie, Junior and Senior.
Many people race worldwide in Spec series such as Rotax Max (a Touch-and-Go class) or those using the Yamaha KT100 engine.
Karting as a learning tool
Kart racing is usually used as a low-cost and relatively safe way to introduce drivers to motor racing. Many people associate it with young drivers, but adults are also very active in karting. Karting is considered the first step in any serious racer's career. It can prepare the driver for high-speed wheel-to-wheel racing by helping develop quick reflexes, precision car control, and decision-making skills. In addition, it brings an awareness of the various parameters that can be altered to try to improve the competitiveness of the kart (examples being tyre pressure, gearing, seat position, chassis stiffness) that also exist in other forms of motor racing.
Most current Formula One racers grew up racing karts, most prominent among them Michael Schumacher, Ayrton Senna, Alain Prost, Fernando Alonso, Scott Speed, and Kimi Räikkönen. Many NASCAR drivers also got their start in racing from karts, such as Darrell Waltrip, Lake Speed, Ricky Rudd, Tony Stewart, and Jeff Gordon.
Racing schools such as the Bondurant Kart Racing School and Endurance Karting School have come along for novice and advanced karters.
As well as "serious" competitive kart racing, many commercial enterprises offer casual hire of karts. Such karts are usually powered by small, detuned four-stroke engines and are far slower than the fully-fledged competitive versions.
- Kart circuits
- Micro kart
- CIK-FIA web site
- ekartingnews.com (see 'New to Karting' link at the top of the page for a good introduction and FAQ)
- Karting History USA & Karting History Europe
- Endurance Karting The largest US kart racing school and race organizer
- MSA - Motor Sports Association Governing body for motor sports in Great Britain
- Rear Engine American Racers Group that promotes and defines guidelines for rear engine vintage racing karts in the US
- VKA - Vintage Karting Association Support of vintage Go Karts originally manufactured from 1956 to 1975 (US)