Abrasive Friction Vs Adherent Friction Part 1

Part 1

There are two types of friction involved when you put your foot on the brake pedal, abrasive friction and adherent friction. In part one of this series we are going to cover the basics of abrasive friction and what exactly is happening.

What Is Abrasive Friction?

Simply put, abrasive friction is what happens when the brake pads are pressed against the rotor. It’s called abrasive because the only force that is stopping the rotor from spinning is friction. And when two brake pads are pressed together the friction becomes great enough that it stops the rotor. Because it is abrasive, this generates great amounts of heat. Heat can then soften the rotor, break down the particles of the brake pad, and cause overall failure of the brakes and rotors.

Does Abrasive Friction Cause Problems

Most brake systems that come standard on a vehicle are abrasive friction systems. The two problems associate with this type of braking system is heat and wear. First, heat. When there is nothing cooling down two different materials rubbing together under extreme pressure and spinning at high speeds, the temperatures rise very quickly. Again, this can cause heat that will break down the material of your pads and rotors and drastically worsen your braking distances. Second, wear. Two materials being forced together at high speeds will break the material down. And when this happens through abrasion, they break down much faster. This is why most stock brakes will have to be replaced at around 30,000 miles.

Other Issues

One other big issue with abrasive friction braking systems is brake dust. Again, because of the extreme pressure and speeds of these material hitting each other, the material are ground into a fine powder or dust. Have you ever noticed if you haven't washed your vehicle in a while your wheels turn brown? That is because your brake rotors are slowly turning to dust. This is one of the most damaging bi-products of abrasive fiction. Brake dust is toxic, very toxic. At a basic level it can break down the metal of your rims, frame, and vehicle body. It also will dull and break down the paint. On a much more severe level, brake dust is extremely harmful to the environment. The average car’s brake pads and rotors can have any of or all of these materials in them; asbestos, copper, cadmium, lead, mercury, and chromium. Although typically not enough is released to be harmful to humans it can be very damaging to wildlife. These materials are what’s called “genotoxic.” Genotoxic means that it can mutate the cells of an organism. This leads to mutations and cancer.


Abrasive friction rotors are standard with most vehicles. If you're currently driving a vehicle with this type of braking system don’t freak out! But as we will get to in part 2 of this series there are much better options for your safety, performance, and health.

Allan Sicat