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Tkart magazine

Tech Focus | Accessories and materials to lighten the kart’s weight

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25 June 2019
In karting and in motorsports in general, weight has a fundamental function to achieve the best performance possible. For this reason, there are various accessories and materials designed to be lighter, thus being particularly suitable especially in those categories where the minimum weight is very low, such as the international Ok and KZ by FIA Karting.

To speak about “weight reduction” for a vehicle as simple as the kart may seem like a subject with few topics available. Wrong! In fact, the objective of reducing the weight of the kart as much as possible encompasses every single component of the vehicle, which can be analyzed precisely from the perspective of obtaining a lighter version of it, both through the use of materials having a low unit weight and through particular manufacturing techniques. Moreover, precisely due to the essential nature and innate lightness of the kart, it must be taken into account that even the difference of few grams can be proportionally be very important than in other motorsport categories.

Weight is the factor which determines the inertia to the movement. At the theoretical level, the formula of linear motion is: F = m * a, where “F” is the linear force of thrust, “m” the total mass of the kart and “a” the linear acceleration. Applying these formulas into practice, means that the linear acceleration (a) directly depends on the force which generates the linear movement of the object, while it is inversely proportional to the mass (m). Translated, the heavier a vehicle is, the greater the force needed to determine proper acceleration.
There are several accessories which can be used to reduce the overall weight of the kart. The fundamental thing to remember is that, in the general calculation of the kart, even a few grams of reduced weight on a single element becomes important once it is combined with all of the other weight saving components. Above all, the accessories from which a reduction of weight of the kart that make a difference are the floor plate, hubs, fairings and the various support elements. Additionally, almost all manufacturers are very attentive to the “weight” issue during the production phase of the frames and braking systems.
The floor plate is an important element in a kart, both in the the setup of the vehicle (depending on its fastenings, it is possible to “release” or decrease the front torsion), and the weight. In this perspective, the use of a resin floor plate makes it possible to lose a considerable amount of weight compared to the standard aluminum version. IPK, Manufacturer of Praga Kart, OK1 and RS Kart chassis, offers three different types of resin floor plates, which vary in the thickness of the woven fibers. The various models have a clear difference in terms of weight and flexibility, this is a clear improvement  in regard to the performance of the vehicle.
The scale is the best instrument to understand the actual difference between the different floor plates of the IPK line: Aluminum floor plate: 1058 gr IPK “blue” fiber floor pan, thickness 3.3 mm – 815 gr IPK “green” fiber floor pan, thickness 1.6 mm - 568 gr IPK “red” fiber floor pan, thickness 1.3 mm – 158 gr The weight difference between the aluminum version and the lighter resin version is an outstanding 900 grams. Attention to focusing on the “lighter weight”  may not always be the best solution because, as mentioned before, flexibility changes, in a significant way amongst the various floor plates, and must be taken into consideration depending on the setup that the kart needs.


The magnesium components make it possible to considerably lower the weight when compared to the use of the same accessories in aluminum. The main differences can be found in the wheel hubs and in the axle bearing casing. As for the hubs, the difference in materials affects the chassis setup as well. Summarizing, it can be said that the aluminum hubs have a lower rigidity, which leads them to be the most suitable option when looking for an increased grip on the track but can decrease in the overall smoothness of the ride. Conversely, magnesium hubs are more rigid than aluminum. During a race they maintain the rim’s temperatures more consistently and directly benefits the tires performance. Magnesium, therefore, “frees up” the setup, thus making it the ideal choice to be more competitive on dry track conditions.
We weighed the hubs and the axle bearing casing in the aluminum and magnesium versions. Here are the results: Aluminum Hub: 365 gr Magnesium Hub: 295 gr Aluminum Casing: 273 gr Magnesium Casing: 202 gr If one considers that a kart has four hubs and usually there are three casings mounted, one can understand how the “magnesium kit” can significantly decrease the weight of the kart. Respectively a difference of almost half a Kilo (493 gr).
There are many homologated fairing kits on the market. Although at the beginning their shapes were very squared and their purpose was only to protect the kart and the driver, in the following years it was mostly the aesthetics that guided the choice of designs. Today, the majority of the kits are computer designed using CFD software and aim at improving the air penetration and drag coefficient. All of this, however, without forgetting about the weight which is by no means a secondary factor in the choice of the fairings, especially when one wants to replace an older kit that has an expired homologation. The benefit in regard to weight, in this case, will be considerable. Amongst the most recent homologation models, we can mention the Dynamica kit by Eurostar, the accessory department of Parolin Racing Karts, which produces fairings that are incredibly lighter.
The chassis and the braking system account for an important percentage of the karts total weight. Despite this it is clear to everyone how a frame is certainly not chosen by drivers based on their weight. The same applies to the brake system. It is proper and fair to highlight the consistent and overall attention that is given to this aspect by the manufacturers who increasingly endeavor to design and construct lighter products without affecting safety and reliability. Several chassis approved by the latest homologation, intended as bare frames, have adopted some solutions precisely from the perspective of implementing a lightening of the vehicles. For example, the brake pump support is produced using different solutions: a casing weighs less than a welded plate. In the same way, in secondary tubes, care is taken to use a smaller diameter, which weighs less and the main tube generate less heat during welding (the diameter of the main tubes, instead, does not depend on the weight and follows other logical factors of efficiency and adaptability, generally related to the categories for which the chassis is designed). As for the brake system, the accessory in which the most sensitive improvements have been made is the caliper, from which all the excess material is removed. In this sense, calipers machined from a solid block of material will have a  smaller overall dimension, consequently less weight, thanks to the construction techniques.
The various supports which are mounted to sustain the different engine components (muffler support, silencer supports in KZ karts, air filter support…) are undoubtedly secondary accessories yet they too add weight to the kart. The same is valid for the radiator brackets and the clutch lever on shifter karts. In these cases there is the possibility of choosing by verifying the weight first. For example, an aluminum clutch lever machined from solid block of material will be more accurate even considering the smallest of details, yet it will certainly weigh more than a molded one.
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