Your Cart

Kart Classes Explained

Kart Classes Explained

Karting has classes for boys and girls for every age, size and ability from age 5 upwards, but sometimes the sheer number of options can be somewhat confusing.

In short, there are six different categories and within each category there are different types of engine that you race with:

· Bambinos: Aged 6- to the end of the year of their 8th Birthday they can start from age 5 with Rookie Racing on a racing academy days at Fulbeck.

· Cadets: Aged 7 – 13

· Intermediate Cadets: Aged 10 - 13

· Juniors: Aged 12- 17

· Seniors: Aged 15+

· Gearbox for karts with gears: Age 16+ 



You can begin your Karting experience in Bambinos between your 6th and 8th birthdays or from 5 on the Rookie Racing Academy Day at Fulbeck. The karts and engines must be registered with the MSUK (Motor Sport UK), and the driver must be signed off as competent by an ARKS Instructor or Examiner before taking part in an MSA event.  Only time trials are permitted, the karts leave at set intervals on specially approved mini circuits, and are timed.  The drivers are graded into Gold, Silver and Bronze categories and their record cards updated.  Everyone will receive a certificate of attendance. The only engine allowed is the Comer C50 with a logbook from Zip Kart, and the only tyres are Le Cont all-weather. Rookie Racing will make sure you're prepared and ready to take your license. If you like, you can even take the test hiring one of our karts.


Boys and girls can start racing karts at the age of 7 in one of the cadet classes. They can continue until the end of the year of their 13th birthday, although they may be getting too heavy by then and move into certain Intermediate classes from the age of 10. The three cadet classes are described below and all are permitted to race together. All have a centrifugal clutch and a recoil starting cord. 

IAME Cadet - uses a 60cc unsealed 2-stroke Parilla Gazelle UK engine. 

Water swift New class - uses iame water cooled engine 

Rotax Micromax - uses water cooled engine

Honda Cadet - uses a 4-stroke Gx160 engine which no longer has to be sealed. The long life engines are very low-cost but have to conform to a technical specification which is on the website. Most but not all clubs will accept these karts and it has a national championship in MSUK British Kart Championships.

Honda cadet - uses a 4 stroke Gx 200 sealed engine and also an intermediate R200 Sealed RPM Racing engines

MSUK - holds the British Championship for the IAME classes, Honda Cadet, Rotax classes, KZ, X30 and TKM Classes.


The 125cc water-cooled Rotax Max TAG (Touch and Go - electric start) categories are now the most popular classes in the UK.

Rotax are more expensive initially but the engine runs longer between rebuilds, so the running costs can be less. Top speeds in the junior classes vary from 55mph to 75mph. Drivers in the 11 year old junior classes must weigh a minimum of 38kg with suit, helmet and boots.  At 13 it is usually 40kg for the more powerful classes.

Junior Max - Junior Max (age 12-17 yrs). It is one of the most powerful junior classes, with top speed about 75 mph.

Junior X30-X30 is manufactured by IAME, permitted by most clubs and has its own British Championship

Junior TKM - (age 11-17) is a popular traditional kart class using a BT-82 piston-port engine to a strict non-tuning regime.  The junior engines have a choice of restrictors between the carburettor and the engine to limit the power, the choice depends on the driver weight.

Junior TKM 4-Stroke - Tal-Ko, who make the TKM engines, also make a 200cc long-life 4-stroke. Not raced at most clubs currently. For 11- 17 yrs with a senior equivalent.

Junior TKM Extreme - A faster 115cc class for championships, having three weights each with a different restrictor size, all with a clutch. Not raced at clubs.

Junior 4-stroke classes - There are other 4-stroke classes for Junior and Seniors which run at certain clubs only e.g. Honda classes and World Formula (senior only). More information on


The most popular senior class in the country is Rotax Max and X30, but there are also other options worth exploring at your local circuit. The once all-conquering TKM Extreme class is now only popular in certain areas, eg in the Midlands, and if you live in such an area it should be investigated. There are other TAG engines as well as Rotax, X30 and TKM. Once some experience has been gained there are further options for the premier international classes, OK is raced primarily at the major championships. 

TKM Extreme - is for 16 yrs upwards (although as in all the classes juniors already racing may move into the senior classes in the year of their 16th birthday). The engine is a115cc variant of the BT82. As with the juniors the chassis have to be registered, and new designs are only permitted every three years, to keep costs down. It’s a popular and economic class and now has a TAG option.

Rotax Max -  the senior equivalent of Junior Max, with a very powerful 125cc TAG engine. Care needs to be taken if starting in this class. Like many classes there is a higher weight variant called Rotax 177 for the heavier driver.

X30-X30 is manufactured by IAME, permitted by most clubs and has its own British Championship

Senior 4-stroke classes -  There are other 4-stroke classes for Junior and Seniors which run at certain clubs only e.g. Honda classes and World Formula (senior only).  More information on


Other than the Junior 85cc category for 13-17 year olds, gearbox karts offer the highest powers and speeds. They can have either 2 pedals - brake and accelerator - like the direct drive classes, or 3 pedals, one of which is a foot clutch, like a car. Most 125’s use karts very similar to the direct drive karts except for the four wheel brakes. They have a hand clutch mounted next to the steering wheel, which is only used to move off from a standstill. At most circuits a standing start is used, as opposed to the rolling formation start that direct drive karts have.Gearbox karts can also be used on the long motor racing circuits, although everyone should preferably start on the short circuits which are typically 900 to 1300 metres in length.

KZ UK is the most popular gearbox class. Although a little more expensive than a direct drive class, they can be surprisingly economical to run. The 125cc water cooled engines have six gears, sequentially operated like motorcycle using a gear-lever mounted next to the steering wheel. 0-60mph times are less than 4 seconds, top speed is 90mph on short circuit, 110 - 120mph on long circuit. The ABkC championship is promoted by the NKF and there are now support races for the class in the Super One Series. KZ1 is virtually the same but with more rigid regulations to CIK standard, and is an MSUK British Kart Championship class.

Junior Gearbox this class uses an 85cc Honda or TM engine with 6 gears and is for 13-17 yrs. With its four wheel braking it offers the youngsters an experience close to a single seater race-car. It’s not raced much at all now though. Currently not being run at any club.

250 National this is the most powerful short-circuit class using 250cc single cylinder motocross 5- speed engines. The karts are often equipped with large full width nose cones and wings, especially when used on the long circuits. Top speeds are 100mph on short circuit, 140mph on long circuit. Twin cylinder Superkarts can reach 170mph though. The NKF holds the ABkC national championship. Some clubs offer the 450cc 4-stroke engine class which may be raced in parallel with 250 National but for separate prizes.

210 National a classic class using the Villiers 197cc engine or derivatives. Administered by the drivers themselves through the 210 Challenge group

There are no products to list in this category.