Transfer layer and brake pad bedding procedure

Why some brake pads need a bedding procedure to apply a transfer layer onto the rotor

There are two types of brake pad friction materials; adherent and abrasive. Adherent brake pads creates friction and heat by depositing a thin “transfer layer” of the pad’s friction material onto the face of the rotor during the “bedding” process (more on that below).  Once it’s applied, all future braking is accomplished by pressing the pad against the matching layer on the rotor. In very simple terms; adherent friction works because the “sticky” brake pad rubs against a “sticky” layer of the same material on the rotor. That’s what stops the vehicle.

The heat generated during stopping gradually destroys the transfer layer while simultaneously laying down a new layer of friction material. The process repeats over and over until the pad is used up. Organic and ceramic style brakes are examples of pads that utilize adherent friction, which is why they don’t wear out the rotors nearly as fast as abrasive friction.

Abrasive brake pads, as their name implies, create friction by rubbing a hard coarse friction material against the rotor. Semi metallic brake pads are an example of abrasive friction material. Abrasive friction material tends to wear out the rotor rather than the pad.

The bedding process varies depending on the brake pad’s formulation

The process of heating the pad to apply the transfer layer is referred to as the “bedding” or “Burning” process. DIYers often call it the break-in process. The actual procedure of applying the brakes in multiple applications varies between brake pad brakes and model numbers.

For example, some racing pad brands recommend driving at a high speed and then performing multiple hard stops with no lag time between stops. For example, they may recommend a hard stop from 60-mph to 0-mph followed by immediate acceleration to 60-mph and another hard stop. Repeat the recommended number of times.

Street brake pad manufacturers, on the other hand, often recommend a more gentle procedure. Their bedding procedure is often a moderate stop from 30-mph to 0-mph with a 30-second wait period to allow the brakes to cool before repeating the procedure. Refer to the brake pad manufacturer’s installation instructions, because there is no one-size-fits-all approach to laying down a transfer layer.

Failure to properly bed brake pads will result in uneven braking and brake pedal pulsation, mistakenly referred to as warped rotors.

©, 2022 Rick Muscoplat