Kart Braking system

In go kart there is a disc braking system that is a system in which wheel slowing down is obtained applying a braking torque by means of one or more couples of pads, that act on a disc, integral to the wheel, and then slow down the wheel by friction.
According to category, there are different kind of systems adopted in karting. In 100cc, there is only a disk, mounted on rear axle, while in 125cc there are brakes on both the front wheels. The differences depend on the different entity of engine powers and then to the different speeds reached, In 100cc, speeds are low and brake should not have an excessive effect, while in 125cc the higher speeds need a more effective braking action.
The system is made of three main components: discs, callipers and pads, plus all the system needed for the actuation (pedals, pumps and various connections).
Discs, normally produced in the measures 200mm for rear brakes and 125mm for front brakes, are made of a special carbon chromium steel, and are drilled to improve heat exchange. This is a fundamental aspect in braking system functioning. Actually we have braking powers of about 60-100 cv that transform vehicle kinetic energy in heat that must be quickly evacuated. Dissipation can be notably improved drilling the discs, obtaining also an increase in friction coefficient between pad and disc, and also using a pair of disc, in order to increase ventilation.
It’s mandatory that heat is correctly evacuated from the system. A non optimal heat exchange, in fact, can lead to pad material vitrification, with a fall in braking performance. Furthermore, if the heat is not properly evacuated, there can be a heat flow to the braking fluid and, if this reach the boiling point, the whole system can become useless.
The presence of holes on disc surface can also improve water evacuation, improving the performance on wet track.
Discs are produced from sheet metal, by means of laser cutting that allow to obtain an excellent finishing. Then discs are subject to an heat treatment to improve mechanical performance and the turned, milled and grinded.
Concerning pads, they are made of carbon-kevlar, a fireproof material made of a carbon based matrix (that provides friction) that hosts the kevlar fibres (that give solidity to the structure).
The production process is the following. Fibres are first put in a die and then compress together. Then they are inserted in an oven and then heated to 1000°C. A gas is then introduced in the furnace, to deposit carbon on fibres. After 500-800 hours, the material is dense and compact and is the machined to final dimensions.
Finally, let’s see calliper manufacture process. Calliper and disk carrier are realized from a block of anodized aluminium (usually ergal) by means of conventional machining operation, usually performed on numerically controlled machines.


Ing. Fabio Renzi
TVK Project s.r.l.
Motorsport software and consulting
Via Ignazio Guidi, 44
00147, Roma

renzi@ing.uniroma2.it
fabio.renzi@tvk-project.com
www.tvk-project.com

Phone +39 0672597136