The Kart Seat: Types, Materials and Setup
The mechanic asks you to get into the kart and asks: how does it feel? The right answer is not just comfortable or uncomfortable, because the seat in a kart is not about ergonomics. It is a setup variable just like the axle or the caster.
Anyone coming into the world of karting for the first time looks at the seat the way they look at a car seat: something to sit in. Then they go out on track, the kart does not turn as expected, and they look for the problem elsewhere. Often it is right there: a seat that is too wide, weight that moves around in the corner instead of transferring to the outside.
Understanding how the seat works (why one shape is chosen over another, what flexibility changes, how the position of the weight affects behaviour on track)
is the starting point for working effectively on setup.
In short A flat bottom lets you lower the seat and the centre of gravity further; a round bottom is more common at amateur level and more comfortable. The right size hugs the torso without play, and the flexibility of the seat also affects how the kart behaves.
It is not just ergonomics
A kart seat is not chosen only according to the driver’s size. It is a setup variable just like the axle or the caster.
The reason is structural: a kart has no suspension. The flex of the chassis is the only system that absorbs track irregularities. The seat, rigidly fixed to the chassis at 4 points, is part of this structure. Changing its stiffness changes the way the chassis deforms in corners, and therefore how load is transferred to the wheels.
The key variable is not just the material, but the flexibility: it is by working on this parameter that you get the most significant changes in behaviour on track.
In addition, the seat carries the heaviest load in the kart: the driver. Its position determines where the centre of gravity of the kart+driver system sits: forward, back, higher or lower. The standard distribution is 55-60% at the rear and 40-45% at the front.
The types: flat bottom or round bottom
There are two main types.
Flat bottom: it lets you lower the seat further, lowering the centre of gravity. Less comfortable than the round bottom, but preferred by those who want to optimise setup.
Round bottom: more comfortable and more common at amateur level. Less freedom in height positioning.
The material: fibreglass
Kart seats are made almost exclusively of fibreglass, at every level. The most qualified manufacturers use advanced lamination systems to obtain a more even resin distribution and a better stiffness-to-weight ratio.
Carbon seats exist but are a niche rarity. The real parameter to work on is flexibility: a stiffer seat is not automatically better, and a more expensive one does not automatically make you faster.
Some manufacturers offer seats with inserts: stiffeners that can be applied to the side surface to increase stiffness gradually. It is a practical way to adapt behaviour without replacing the seat every time.
How to choose the size
Seats come in different sizes: always check the size charts of the various manufacturers to identify the most appropriate one.
The right size hugs the driver without leaving lateral play and without squeezing. A seat that is too wide lets the driver move around in corners, so the weight does not transfer in a controlled way. One that is too tight can restrict breathing.
The correct procedure: measure the hip width of the seated driver (in racing gear) and compare it with the manufacturer’s charts.
The 4 fixing points
The seat is fixed to the chassis at 4 points: two side supports and two in the lower part of the chassis near the floor tray; one or two rear supports can be fitted to anchor it to the chassis brackets for the rear bearings. The supports can be adjusted within certain limits to change height and tilt.
A detail we often see overlooked: the seat is fitted in an asymmetric position. The right support is slightly further from the axle than the left. It is not a fitting mistake, it is intentional. It compensates for the weight asymmetry created by the engine and transmission, which sit on the right side.
How the position affects setup
Forward/back: even just 1-2 cm changes the weight distribution. Moving the seat forward loads the front and increases grip on entry. Moving it back unloads the front and increases rear traction.
High/low: lowering the seat lowers the driver’s centre of gravity, improving stability in corners. The goal is always to get it as low as possible relative to the chassis tubes, within the physical limits of the structure.
Frequently asked questions
What is the difference between a flat-bottom and a round-bottom kart seat?
A flat bottom lets you lower the seat further on the chassis, lowering the centre of gravity, preferred by those working on setup optimisation. A round bottom is more common at amateur level: more comfortable, but with less freedom in height adjustment.
How do you choose the size of a kart seat?
Measure the hip width of the seated driver, in racing gear, and compare it with the manufacturer’s charts. The right seat hugs the torso without lateral play and without squeezing. A seat that is too wide lets the driver move in corners, compromising weight transfer. If in doubt, the TKS RaceLab team is available to help you choose at tksracelab.com.
Why is the seat considered a setup variable in a kart?
Because the driver accounts for 30-40% of the total weight of the system. The position of this weight (forward, back, high, low) determines how the kart distributes load on the wheels in corners. Moving the seat by 2-3 cm has measurable effects on track. At TKS RaceLab it is one of the parameters we adjust systematically.
Does the seat material change performance?
The base material is almost always fibreglass. The variable that really matters is flexibility, not the material: a stiffer seat transfers load differently from a more flexible one. Carbon seats exist but are a rarity; the parameter to work on is flexibility. At tksracelab.com you will find fibreglass seats for every class.
Want to find the right seat for your build and driving style? With our Arrive & Drive you get the kart, the track and the technical support of the TKS RaceLab team, at Lonato, Franciacorta, Cremona and Ala.Discover Arrive & Drive →
🛒 Seats, supports and kart spare parts available in our shop: tksracelab.com
👉 You will find seats in our shop: Maranello MT W1 resin seats.
Conclusion
The seat is not a passive accessory. It is part of the setup. Choosing the right shape, the correct size and the optimal position is the first step to having a kart that responds as you expect.
Find out more: The kart seat: complete guide to types, fitting and effect on setup → · Why the seat position changes kart setup →
Questions about this topic?
Message us on WhatsApp: we answer personally, with the experience of people who live at the track. And if you want to drive a real racing kart, with Arrive & Drive you get into one of ours, ready on track. The right spare part? You will find it in the shop.
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Read also: Kart axles: complete guide to choice, setup and replacement → · Kart wheels: complete guide to materials, sizes and choice → · How to fit a kart seat: position, height and angle → · Kart axles: soft, medium and hard → · How to change a kart axle → · Kart tyres: the complete guide →
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Author: Sergio, TKS RaceLab | Published: 11 June 2026 | Updated: 4 October 2026
TKS RaceLab is the Italian online store dedicated to karting: spare parts, accessories and everything you need to get on track. With Arrive & Drive you arrive at South Garda Karting (Lonato), Franciacorta, Cremona or Ala and find your kart ready to go. No hassle, just driving.
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