KART BRAKING SYSTEM: THE DIFFERENT TECHNICAL AND MANUFACTURING APPROACHES COMPARED

Gianluca Covini

04 December 2023 • 18 min. read

Is a self-ventilated, drilled brake disc better than a slotted one? Are radially mounted calipers preferable to side-mounted calipers? And what about master cylinders: which are more suitable for karting, those with direct or lever actuation? To finally get answers to these (and many other) questions, here is the definitive guide that explains the various schools of thought present in our sport, regarding the design and manufacturing of brake system discs, calipers, pumps and fluids

WHAT IS IT?

HOW DOES IT WORK?

IN PRACTICE

In the design of a braking system, the choice of one technical concept rather than another can significantly affect the operation of the system, the feeling it gives to the driver and the durability of its parts. There are different technical concepts on the market because, in all likelihood, each manufacturer adopted its own in the past and then, evolution after evolution, approval after approval (what are approvals? Read "Dossier | FIA approvals: what they are, what they are for, how long they last... The Ultimate Guide!), stayed with it, maybe even just for marketing logic and customer loyalty/habit. It therefore happens that the designers of the various manufacturers often find themselves having imposed "parameters", in relation to which they have to design a system that works in the best possible way.

However, from the driver's point of view it is impossible to say a priori that one solution is better than another. In fact, it depends on how the system has been designed, the degree of development and how the other components work in synergy to make the whole system work at its best. But how do you navigate such a varied market, in which, in addition to the specific and original equipment components supplied by each manufacturer, there are also aftermarket components? To help you make the most informed choices, we describe the most common manufacturing choices, highlighting the pros and cons, concerning the main components of the braking system: discs, calipers, brake master cylinders and brake fluid.

Editor's Note
In this article, we analyse the general and most common design and manufacturing choices, net of specific details undertaken by each manufacturer.

Technical-manufacturing decisions that have their own pros and cons with regard to the main components of the braking system: discs, calipers, brake pumps and brake fluid

The braking system of a kart (represented here is one of a shifter kart, therefore with a brake disc at the rear and two at the front) is composed of different components (calipers, brake, pump, hoses, pads, etc.), each of which can follow a different manufacturing approach. For example, the brake disc can be solid or self-ventilated, drilled and/or slotted; the pump can be controlled directly or by a lever; The oil circuit can be made for glycol or silicone-based liquid. And so on. It is important to know the reason for certain technical choices, but bear in mind that there are an infinite number of factors involved between theory and practice!

WHAT IS IT?

HOW DOES IT WORK?

IN PRACTICE

Smooth Full Disc

The full, smooth disc is the simplest and cheapest variant of the brake disc, suitable for smaller karts, such as MINIs. It is generally heavier, with the same diameter and thickness, than self-ventilated and/or perforated ones. Very popular in the past, over time they have fallen into disuse and it is increasingly rare to find it in shops or on the competition fields.

Smooth self-ventilated disc

The self-ventilated disc is very common, especially in cars. Ventilation is obtained through radial ducts, from the centre of the disc to the edge, which allow the passage of air which allows heat to be removed, from the inside to the outside, during the rotation of the disc. The "useful" thickness of a self-ventilated disc is obviously smaller than that of a solid disc, because the central part is hollow, so its durability is theoretically shorter.

Self-ventilated perforated disc

A self-ventilated and perforated disc, compared to the previous type analysed, adds a series of holes on the surface that comes into contact with the pad. The number of holes is variable, as is their arrangement: there are simple "patterns" and others that are more complex. The drilling of the face of the disc has two purposes: the first is to facilitate the removal of heat, allowing the passage of air through the thickness of the disc; the second is to allow water to drain in case of rain and, therefore, faster drying during rotation. However, the continuous passage of the holes on the surface of the pad accelerates the process of material removal, increasing the wear of the pad.

Brake disc
The first element we put under our magnifying glass is the brake disc (in the article "Technique | The secrets of the brake disc", you can learn more about how it works and the concepts behind its manufacturing), which, over time, has been the subject of numerous experiments and variants proposed by the various designers, all aimed at solving the two main problems that affect its performance: overheating (caused by the forces involved in the braking process, to learn more read "Technique | The dynamics of braking") and deposits of residues (e.g. pads) which, over time, accumulate, risk negatively affecting the friction between the caliper and the disc. Nowadays, the most performing discs have special mechanical processes: holes on the face of the disc, to allow a more uniform dispersion of heat and better water disposal in case of rain, or radial grooves, to facilitate the disposal of dust and debris from rubbing. Another typical feature of the most performing brake discs is the presence of radial channels, which during rotation act as a passage of air to remove heat, which is why they are called "self-ventilating". Finally, the disc can be rigid or floating, i.e. free to move, by a few millimetres, in a radial direction. With the latter type, the contact between the pad and the disc takes place in a more symmetrical and uniform manner.

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