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T11 Kart Racing Seat

T11VG Kart Racing Seat



The T5 was introduced in 1990 and was the first kart seat to feature the familiar "flat bottom" now used by nearly every manufacturer. The original T5 model was smooth and glossy on the back and always fully covered. The covering started to disappear when constant rib problems could not be solved with the seat padding alone. Steve Tilett started wrapping the drivers in a hard skin of plastic with a foam lining and this became the Ribtec product. The Ribtec started the revolution in hard rib protectors, which meant that covering was no longer necessary. With no need for a cover the T5 seat moulding was flipped around and made into what was called the T5 Reverse. Nowadays this more upright shape is still used but mostly by the 8 to 12 year old drivers. The 63° back allows a more powerful shoulder turn, which helps the very young racers. The three popular sizes Ccd, CL and XScd cater for this age range and are made in the by our special production method which gives excellent quality, consistent rigidity and a smooth surface inside and out. These are also available in a striking vivid neon colour, or with a front surface of silver or carbon fibre.

The most popular rigidity for low power 60cc two stroke Cadet/ Minikart classes is the super soft T5 VTi. A very small Junior driver in a full size kart may choose the T5t or T5VG for racing classes like OKJ, Mini X30 and Minimax. For children’s four stroke classes the most popular rigidity is T5 standard.

A T5t seat was used by Lando Norris to win the 2014 World KF Championship.

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Details on the Contact us page.

All uncovered seats are priced without a fitting kit.



As used by 2020 Junior World Champion Freddie Slater

The T11 is the most popular adult shape and the one most often used by professional karting teams and manufacturers. With every generation growing taller, a new seat was needed. A large flat area on the base was created and combined with a more reclined back angle of 58°, lowering the head height significantly. Whilst lowering the body weight gives a performance advantage, it is important to maintain an upright shoulder position to allow enough power to be transferred to the steering. The driver is likely to "pull to steer" if they are too reclined, which is bad for handling and body stability. The T11 shape enables the correct upper torso angle to retain firm control and therefore performance.

The T11 is manufactured using our own highly developed moulding technique, which makes a seat with a consistent laminate weight and thickness. It also has smooth surfaces front and back, which keeps the seat looking professional and clean. Unlike previous mechanised production methods, this unique system gives us the opportunity to tune the rigidity. The T11 model also benefits from a specially developed high strength resin and it contains a much higher fibre to resin ratio than regular laminates. This makes the seat less likely to splinter during drilling and more able to withstand impacts. Another benefit of this system is we can aesthetically change the seats to have a beautiful carbon, silver, or vivid neon coloured finish.

The four rigidities made available in the T11 are the ones mostly used in current chassis designs. Over recent years the chassis have required more flexible seats. Therefore, the standard rigidity is the most rigid of the four offered. The two most popular rigidities are the mid-range T11t rigidity, which is frequently used in X30, OK and KZ. (This "t" stiffness sits in between the flexible VG and the T11 Standard.) and the very popular soft and flexible T11VG. The most flexible specification is the Vti which is predominantly used in the T5 shape in very low torque karts in the 8 to 12 year old categories.

The T11 size range is large and includes many sizes in a "WT" wide top version. These help correctly fit drivers who either have narrow hips and a wide chest or use a very thick rib protector, such as the protectors we make bespoke on individual drivers.

Special order T11 hand laminated seats made for drivers with wide hips are available in three sizes S, Manetti and ML

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Details on the Contact us page.

All uncovered seats are priced without a fitting kit.


There are many factors to consider when choosing a new kart seat.

If you have had a seat in the past. Do you know the size and shape?

Does it still fit?

If not where are the gaps or pressure points?

Will the rigidity suit your new kart/engine combination?

If you are in a team will they be happy if you choose a different shape?

Choosing a shape

Shape does not make as much difference as the teams would have you believe, but they will be nervous of miss positioning the seat and may want you to use the shape they are regularly fitting. This is fine until the seat is not the right fit for you. An ill-fitting seat can cause a driver to damage their body or hang on the wheel, neither of which are good for ultimate performance. Different shapes are fine if they are put in the chassis with the drivers back in exactly the same place and made with the same materials, then they will handle the same. That said a significant angle change of the back will alter the handling, especially for bigger driver and this scenario should be viewed differently.


The most common shape used now is the much copied 58° T11 which is by far the most popular shape. The T11 has a huge range of 22 sizes. Drivers from a 12-year-old up to a 130 kg man, are all catered for. Many of the T11 sizes solve age old problems. WT (Wide Top) sizes have been made for drivers with a slim hip and an athletic torso, (or maybe a thick rib protector). Also, available are a series of WH (Wide Hip) sizes for drivers that end up with severe bruising in this area.

If you are 12 years old or above and not over 1.8 m, this T11 is the seat you will most likely use.


The 63° T5 is ideal for the 8 to 12 year old drivers. The more upright seating position helps them keep good control and enables better vision over the steering wheel for a shorter driver.


The reclined 38° T9.5 is for the very tall drivers. This can be used to good effect, lowering the centre of gravity for drivers whose height makes the kart unstable on fast corners.

Choosing a size

This is important, as a good fit is essential for the protection of the driver and the handling of the kart. If a driver is loose in a seat they will pull to steer, pulling themselves out of the kart, making it bounce at the slightest provocation.

To assess whether the size of a seat that you have in your possession is correct, sit the driver in the seat and feel the gaps over the leg bone, the hip bone and down the length of the ribs, from top to bottom. This must be done with any rib protection in place, but the race suit is not so important unless it has integral padding. The rib protector when worn tight, should not move inwards as the driver sits back in the seat. Once sat back in the seat, it should be difficult to squeeze your fingers between the seat, your ribs, hip and leg bones. It’s important that all the points are evenly pressured and no one element is either loose or pinching. If one area feels loose, some firm foam stuck between driver and seat is acceptable. If it is pinching anywhere you need a different size.

To assess the size without having a seat in your vicinity, we find that denim jeans waist size, weight and height are good indicators. Coupled with information about the chest circumference and rib protector type. An over thick rib protector can make two sizes difference and leave you with very loose hips, so this is to be avoided (i.e. buy a P1) or accounted for with a WT wide top T11 seat.

Choosing your kart seat

Choosing a rigidity

Tillett Racing Seats were the first to discover that seat stiffness affected lap times.

Changing the seat rigidity alters the amount of weight transferred to the outside front tyre, it is also partly responsible for the amount the inside rear wheel can lift through the corners. This gives you the ability to balance a chassis that may not be perfectly adjusted for the track surface, driving style or weather conditions.

Standard OEM seats supplied with many karts are made to a price and are often inconsistent in rigidity and strength. To make sure that the seat you buy this year will be the same size and rigidity as one you buy next, Tillett Racing Seats are made to set specifications. They are also unique in that they can be bought in 8 different rigidities including the hybrid VGR /VRS. The rigidities which are available in each shape are shown on the size / rigidity guide.

Choosing your kart seat

New Style T5, T9.5 and T11 seats - These are made with a process that allows different rigidities to be made using a highly accurate mechanised process and the system can make seats weighing within 5g of each other. Therefore, the rigidity can be tuned to the specification equalling the tunability of the handmade seats. There are four rigidities in the "New style" specifications and all four are relevant to the rigidities commonly used by the kart chassis in use today. The New Style T5, T9.5 and T11 are cut by robot to increase the accuracy of the product.

Flexible VTI, and VG - The flexible VG seats are a favourite with the Rotax Max drivers and almost always used to win the competitive Euro Max series. "V" seats are made of non-standard composite materials; they are lightweight, and we find that many people use the "VG" seat to good effect in all sorts of different classes.

Using the same material specifications, there is also the ultra-flexible VTi and this is ordered by customers determined to get the most flexible seat possible. The two stroke Cadet / Minikart classes seem to prefer this specification.

VG and VTi are two rigidity specifications that are available in the New Style T5, T9.5 and T11 seats.

The " t " - rigidity is currently the most popular stiffness with OK Junior, OK Senior, X30 and KZ and sits in between the Standard and VG rigidities.

The T11t spec was used in an OTK chassis to win the 2017 KFJ World Championship with Dexter Patterson and Jorrit Pex used it to win the 2019 KZ European Championship.

The " t " is one of the rigidities available in the New Style T5, T9.5 and T11 seats.

Standard Rigidity - This is based around basic uncovered seats. The standard rigidity model of each shape only has the letter T plus its number, for example the T8.

" Standard " is one of the rigidities available in the New Style T5 and T11 seats.

It is also possible to make the following rigidity specifications in all the handmade seats.

Rigid " R " - A thicker, stiffer version of the standard seat is shown by including the letter "R" after the T number.

Extra Rigid XR - Commonly known as 'The Rope Seat' due to its filled edge. The seat has enormous strength and rigidity around the perimeter, while still allowing the front to flex a little. This extra rigid specification is designated by placing the letters XR after the T + number. They have a dramatic effect on the chassis handling.

The VGR - For customers who require a rigid seat across the seat stays whilst still allowing some diagonal flex, we have the VGR. This seat has a solid rigid edge which controls the amount the seat can flex. The seat is like a regular soft VG seat in the middle but is much stiffer across the top edge and down the sides. With this seat in the chassis it will reduce the inner rear wheel lift but keep a proportion of the diagonal flexibility.


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