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.
ALUMINUM vs MAGNESIUM
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.
CHASSIS AND BRAKING SYSTEM
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.