Shimano Brake Burn-In Procedure
How to correctly burn in (bed in) hydraulic disc brakes for best performance
How to correctly burn in (bed in) hydraulic disc brakes for best performance
Brake burn-in is an essential step to ensuring proper performance from any disc brake system. Any time a new brake system, rotor,
or pads are installed, the job should not be considered complete until the pads and rotors have been properly burned in. That means
that this process should be performed on all new bicycles as a part of the build process. This guide will explain why the process is
so important and how to perform it properly.
What Burn-In Accomplishes
A properly performed burn-in uses controlled stops to gradually heat the system and apply a thin layer of pad material onto the
braking surface of the rotor. This should be performed on any brake system with a “new” rotor, pad, or both. Once this layer is in
place, the friction between the pad material on the brake pads themselves and the pad material in the transfer layer provides
additional stopping power. This transfer layer becomes one of the most important pieces in the system, and that is why it is so
important to make sure it is applied correctly. Uneven application can result in noise, pulsation, poor modulation, or a lack of braking
power. As the transfer layer is being established, the pads will also be burnished to match the contour of the rotor. This allows
for maximum contact and increases braking power and modulation. This is especially important when installing new pads with
an old rotor, as the rotor will have a slight concavity worn from usage. After the burn-in is complete, the brake system should be
performing at or near its full potential.
Procedure
This procedure should be performed as the final step when installing a new brake set, assembling a new bike, installing new pads,
or when changing rotors - remember, new pads should always be installed when replacing rotors.
1. Select an appropriate location – this should not be on the trail or the road, but somewhere open, flat, and protected
from traffic
2. Put on your helmet, mount the bicycle, and accelerate to 10-15 miles per hour
a. Metallic pads can benefit from higher speeds during the burn-in process, but always maintain a safe speed
3. Apply firm steady pressure to one brake – do not turn the bars, lean the bike, or radically change weight distribution during
braking, as these actions can lead to a crash or uneven application of pad material
4. Release pressure before the bike comes to a complete stop
a. Coming to a complete stop will create a thicker deposit of pad material, which can cause noise, shuddering, or
vibration
5. Repeat this process several times, paying attention to the gradual increase in brake performance
6. Burn-in is complete when there is no longer any improvement from one repetition to the next – this will take at least 10
near-stops per wheel, but may take as many as 30
7. Repeat with the other brake
8. Allow time for the system to cool completely before continuing to ride
or pads are installed, the job should not be considered complete until the pads and rotors have been properly burned in. That means
that this process should be performed on all new bicycles as a part of the build process. This guide will explain why the process is
so important and how to perform it properly.
What Burn-In Accomplishes
A properly performed burn-in uses controlled stops to gradually heat the system and apply a thin layer of pad material onto the
braking surface of the rotor. This should be performed on any brake system with a “new” rotor, pad, or both. Once this layer is in
place, the friction between the pad material on the brake pads themselves and the pad material in the transfer layer provides
additional stopping power. This transfer layer becomes one of the most important pieces in the system, and that is why it is so
important to make sure it is applied correctly. Uneven application can result in noise, pulsation, poor modulation, or a lack of braking
power. As the transfer layer is being established, the pads will also be burnished to match the contour of the rotor. This allows
for maximum contact and increases braking power and modulation. This is especially important when installing new pads with
an old rotor, as the rotor will have a slight concavity worn from usage. After the burn-in is complete, the brake system should be
performing at or near its full potential.
Procedure
This procedure should be performed as the final step when installing a new brake set, assembling a new bike, installing new pads,
or when changing rotors - remember, new pads should always be installed when replacing rotors.
1. Select an appropriate location – this should not be on the trail or the road, but somewhere open, flat, and protected
from traffic
2. Put on your helmet, mount the bicycle, and accelerate to 10-15 miles per hour
a. Metallic pads can benefit from higher speeds during the burn-in process, but always maintain a safe speed
3. Apply firm steady pressure to one brake – do not turn the bars, lean the bike, or radically change weight distribution during
braking, as these actions can lead to a crash or uneven application of pad material
4. Release pressure before the bike comes to a complete stop
a. Coming to a complete stop will create a thicker deposit of pad material, which can cause noise, shuddering, or
vibration
5. Repeat this process several times, paying attention to the gradual increase in brake performance
6. Burn-in is complete when there is no longer any improvement from one repetition to the next – this will take at least 10
near-stops per wheel, but may take as many as 30
7. Repeat with the other brake
8. Allow time for the system to cool completely before continuing to ride
