Bicycle disc brakes have become increasingly popular among cyclists due to their consistent performance in various weather conditions and superior stopping power.
I’ve learned that bedding in the brake pads (and rotors) properly when they’re new is crucial to ensure optimal braking performance.
In this article, I’ll provide step-by-step instructions on bedding in your new disc brake pads.
Importance of bedding-in new disc brake pads
Bed-in is a process of transferring the brake pad materials to the disc rotor using kinetic-to-thermal energy transfer. The bedding-in process, or burnishing or breaking-in, involves a series of controlled braking maneuvers during a test ride.
There are several reasons why bedding-in is essential.
- Removal of manufacturing residues. The bedding-in process helps remove any residues or contaminants from the manufacturing process, which could otherwise hinder proper pad and rotor contact.
- Even distribution of pad material on the rotor. During bedding-in, a thin, even layer of brake pad material is deposited onto the rotor surface. This layer improves the overall contact between the pad and rotor, resulting in more consistent and efficient braking performance.
- Ensuring proper contact between pad and rotor surface. Proper bedding-in helps to establish an even, full-surface contact between the pad and rotor, reducing the risk of uneven wear and enhancing overall braking performance.
How to bed-in new disc brake pads
Follow these instructions for a successful bedding-in procedure. The same process applies to all Shimano, SRAM, and Campagnolo disc brakes.
Step 1. Clean the rotors
Using a clean rag and isopropyl alcohol, thoroughly clean both sides of the rotors to remove any residue or contaminants. Allow the rotors to air-dry completely before proceeding to the next step.
Step 2. Install the new pads
With gloves on, carefully install the new disc brake pads into the brake calipers, following the manufacturer’s instructions. Ensure the pads are seated correctly and securely.
Step 3. Test ride and perform controlled braking maneuvers
Find a suitable outdoor location with a slight incline and minimal traffic. Ride your bicycle at a moderate speed (approximately 15 to 20 mph) and apply the brakes firmly but not so hard as to lock up the wheels or skid.
Repeat this process 10 to 15 times, gradually increasing the braking force with each repetition. This step helps deposit an even pad material layer onto the rotor surface.
Step 4. Perform high-speed braking
After completing the controlled braking maneuvers, ride your bicycle at a higher speed (around 25 to 30 mph) and apply the brakes firmly without locking up the wheels or skidding.
Repeat this process 5 to 10 times, allowing the brakes to cool between each repetition.
Step 5. Cool down
Ride your bicycle at a leisurely pace for several minutes, allowing the brake pads and rotors to cool down completely. Avoid stopping completely during this cooldown period, as this may cause uneven pad material transfer.
Common mistakes and how to avoid them
During the bedding-in process, there are several common mistakes that cyclists may encounter. By being aware of these pitfalls, you can take steps to avoid them and ensure a successful bedding-in process.
- Not cleaning the rotors properly. Failing to clean the rotors thoroughly can lead to poor braking performance and noise. To avoid this issue, always use isopropyl alcohol and a clean rag to remove any residue or contaminants from the rotors before starting the bedding-in process.
- Touching the brake pads or rotors with bare hands. Oils and dirt from your skin can contaminate the brake pad and rotor surfaces, compromising the bedding-in process. Wear gloves when handling brake components to prevent this and avoid touching the pad and rotor surfaces.
- Stopping abruptly during the cooldown period. After completing the high-speed braking maneuvers, allowing the brake pads and rotors to cool down gradually is essential. Stopping abruptly during this phase can cause uneven pad material transfer. To avoid this, continue riding at a leisurely pace for several minutes without coming to a complete stop.
Troubleshooting and addressing issues after bedding-in
From my experience, you may still encounter some issues even after properly bedding-in your new disc brake pad. Here are some common problems and how to resolve them.
- Squeaky brakes. If your brakes continue to squeak after bedding-in, clean the rotors again with isopropyl alcohol and a clean rag. Ensure that the brake caliper bolts and mounting hardware are properly tightened. In most cases, this would solve the problem.
- Uneven pad wear. If you notice uneven pad wear after bedding-in, check the alignment of the brake calipers and ensure that the pads are making even contact with the rotors. Adjust the caliper position or consult your bicycle’s user manual or a professional mechanic.
- Inconsistent braking performance. If you experience inconsistent braking after bedding-in, inspect the brake pads for signs of contamination or glazing. Contaminated pads may require replacement, while glazed pads can sometimes be salvaged by lightly sanding the surface with a fine-grit sandpaper.
Bedding-in FAQ
Can I bed in my new brake pads without replacing or cleaning the rotors?
It’s always best to clean your rotors before bedding-in new brake pads to ensure proper pad and rotor contact. This will help avoid contamination and ensure optimal braking performance.
For me, if the rotors are almost worn, I’ll replace them with the brake pads.
How long does the bedding-in process typically take?
For me, the bedding-in process usually takes 20 to 30 minutes, including the test ride and braking maneuvers. However, the duration may vary depending on the pad compound and riding conditions.
Is it necessary to bed in new rotors as well?
While bedding-in primarily focuses on the brake pads, new rotors can also benefit. Bedding-in ensures an even layer of pad material on the rotor surface, promoting consistent braking performance and reducing the risk of rotor warping.
Can I use sandpaper to clean my rotors before bedding-in new pads?
Fine-grit sandpaper (around 400-grit) can help remove stubborn residue or glazing from your rotors. However, be gentle and avoid removing too much material, which can damage the rotors. After sanding, clean the rotors with isopropyl alcohol to remove any remaining debris.
What should I do if my brakes still feel weak after bedding-in new pads?
If your brakes feel weak after bedding-in, double-check that the brake calipers and pads are properly installed and aligned. Additionally, ensure that the brake cables or hydraulic lines are in good condition and properly adjusted. If the issue persists, consult a professional bicycle mechanic for further inspection and assistance.
Can I use the same bedding-in procedure for mechanical and hydraulic disc brakes?
Yes, the bedding-in process above can be used for mechanical and hydraulic disc brakes. The primary difference between the two systems is the actuation method (cables for mechanical and hydraulic fluid for hydraulic), but the bedding-in process remains the same for both.
Is it safe to bed in new disc brake pads on public roads?
For safety reasons, it’s best to perform the bedding-in process in a controlled, traffic-free environment, such as an empty parking lot or quiet residential street. This will allow you to focus on the task and minimize the risk of accidents or collisions with other road users.
Alex Lee is the founder and editor-at-large of Mr. Mamil. Coming from a professional engineering background, he breaks down technical cycling nuances into an easy-to-understand and digestible format here.
He has been riding road bikes actively for the past 12 years and started racing competitively in the senior category during the summer recently.