Brake pads work be creating friction against the brake disc. As we have covered in the general brake information article, brakes work by converting kinetic energy into heat.
The job of the brake pad is create friction between the disc and the pad to create heat. this heat is then dissipated by the brake disc. Please check the brake disc information article for more details on how brake discs work.
So it sounds like a simple job for the brake pad but there are a few factors the designers have to take into consideration when they construct a brake pad and as with most things, they have to make compromises.
How Brake Pads Work – Compromises
It is generally easy to simply build a brake pad that creates a lot of friction. This pad will be great for driving around town because the car will stop very effectively. However the drawback of having a brake pad with a high co-efficient of friction is that while it may be fine around town, that high coefficient of friction will create immense heat under hard driving.
If the pad has not been designed for hard use it can overheat at high temperatures which leads to a dramatic loss of friction against the brake disc and this means braking efficiency drops dramatically as well.
When a brake pad overheats it gives off gas and also gives of material at an accelrated rate. The gas and material come between the brake disc and the brake pad friction surface leading to the loss in friction.
Making a brake pad that has a high coefficient of friction and is suitable for use on the track is a massive challenge for brake pad manufacturers.
You will usually find that high performance and race brake pads will have a lower coefficient of friction that original equipment (OE) replacement brake pads.
This is so the heat in the brake system is kept lower under hard use.
The other side of the race brake pad coin is that because they are designed to work under extreme temperatures for extended periods of time they do not work well from cold.
It is extremely difficult to satisfy the conflicting demands of high friction, high temperature and low temperature performance, which means brake pads are not usually suitable for road use.
How Brake Pads Work – Pad Selection
Because brake pads can be used on various cars which are used for various purposes, pad manufacturers usually make a selection of compounds which the driver can decide is most suitable for their driving.
The differences between brake pads is down to the materials used in the pad and the mix of the materials in the brake pad.
Some manufacturers use metal in the pad for high temperature resistance and high friction, other use aramid fabrics such as Kevlar and carbon fibre.
Roesch is an example of a brake pad manufacturer that utilises carbon fibre in their brake pad to great effect. While their pads give of dust in our opinion they are the closest pad on the market which offers OE pad levels of performance around town while working in extreme temperatures.
EBC has recently released their BlueStuff compound which they also claim can be used on your daily driver while still be suitable for extended use on the race track.
How Brake Pads Work – The Holy Grail
As track days become more and more popular drivers are demanding more and more from their brake pads. Track days drivers want a brake pad that is safe to use on the drive to the circuit, that can withstand many consecutive laps at the track and at the same time they want a brake pad that does not wear out quickly and does not wear the brake discs excessively.
The use of aramid and carbon fibre in brake pads is moving the braking industry closer to this holy grail but this performance does come at a cost.
Pads which can be used everyday and also on the race track can cost up to 3 times as much as OE replacement brake pads however some of the purchase cost is offset by the fact that performance brake pads can last 2 to 3 times longer than OE spec pads, so some or all the original purchase price can be returned in saved labour costs if the driver pays a garage to change the pads.
How Brake Pads Work – Summary
In general we recommend performance brake pads for every car. To choose your brake pad check out the brake pad manufacturer page on Strikeengine.com. For product information or call your local performance car part dealer for advice and prices.