Disc Brakes

How to silence disc brakes: 9 ways to fix squealing disc brakes

Even in wet weather, the disc brakes provide an encouraging smooth stop.

They are generally very reliable and durable, but disc brakes can make a lot of noise if not appropriately adjusted or dirty. This noise can sound like a “tinkling” sound while driving or a squeak/squeak when parked.

Do you want quiet disc brakes? In this guide, we’ll walk you through the various reasons disc brakes make noise and how to mute them.

Why are my disc brakes noisy?

Disc brake noise can occur for a variety of reasons. We explain some of the most common causes of squeaky disc brakes and offer advice on fixing the problem.

When using disc brakes, it’s always worth wearing a new pair of mechanical gloves or a lint-free rag, as oils from your skin can contaminate the pads and rotors.

If you have doubts about your mechanical skills, take your bike to a reputable mechanic.

9 Ways to Stop Disc Brake Noise

1. Caliper misalignment

One of the most common causes of disc brake friction is a misalignment of the caliper with the rotor.

The caliper must be properly centered. If this is not the case, the brake disc rubs against the inside pad or caliper body.

Granted, in many disc brake systems, tolerances have become very fine, which can sometimes be a tricky task.

If your frame uses a quick release, ensure the wheels are correctly installed before making brake adjustments. It’s better to mount the wheels on the ground than mounts so that gravity can center them. If your bike uses thru-axles, you don’t need to worry about this step.

The easiest way to fix this is to slightly loosen the two bolts that hold the caliper to the frame. They don’t have to be fully released, just enough to allow the calipers to move freely. These are usually four or 5-mm hex head screws, sometimes T25 Torx screws.

After loosening the screws, turn the wheel and pull the corresponding brake lever. Then, without reducing the brake lever, retighten the two bolts evenly to the proper torque, cross your fingers, and solve the problem.

This process repositions the calipers on the rotors, and holding the brakes in place should allow the calipers to align themselves.

Be sure to tighten the calipers to maximum torque before loosening the levers. If you pull the bolt after loosening the lever, the last tightening action can move the caliper a little, and you’re back to square one.

If this technique doesn’t solve the problem, you can try calibrating the calipers with the naked eye. If you’re working in a dimly lit area, try placing a piece of white paper on the floor behind the calipers. The white paper makes the alignment of the caliper easier as it makes the gap between the pads and disc more noticeable.

Some manufacturers, such as Birzman or Hayes, stock caliper alignment tools if your disc brakes are still not aligned after these steps. These are feeler gauges with the exact metal width on both sides to create equal clearance between the disc brake pads.

You will install the caliper calibration tool on the brake disc in the loosened caliper. Once installed, pull the brake lever and tighten the two screws with the proper torque. This usually solves the problem as long as the brake disc doesn’t bend.

The setup process may be slightly different if you have mechanical disc brakes. Most systems consist of one moving disc pad and one static pad. You want to place the fixed pad as close to the disc rotor as possible, then fine-tune the cable tension to ensure the best lever feel.

Suppose the mechanical disc brake is a two-piston construction, such as B. With a Tektro Spyre, the settings related to setting the correct cable tension are the same as for hydraulic systems.

2. The mat is dirty

If your pads are dirty, your disc brakes will make noise. If you drive through oil or accidentally get a degreaser or lubricant on the road, your brake pads can become contaminated.

When cleaning your bike, cover the brake discs and calipers, or spray degreaser on the chain, so it doesn’t get on the discs.

Assuming the wind isn’t blowing in the direction of the rotors, you can spray degreaser on the chain as soon as it hits the crankset under the drive-side chain, as this is the point furthest from the disc brake system. It is best to use a special disc brake cleaner or isopropyl alcohol when cleaning disc brakes.

Alternatively, you can use a chain cleaning device to eliminate the risk of pad contamination virtually.

You can tell if your brake pads are dirty by hearing a squeak when stopped and a noticeable drop in braking force.

The easiest way to fix the problem is to clean the discs and calipers and replace the pads carefully.

If there is still a lot of litter, you can use a blowtorch to burn off the contamination or grind away some of the material. However, this doesn’t always work and is almost always more trouble than it’s worth.

3. Interior Materials

The material of disc brake pads affects noise. Organic places tend to run quieter than metal pads.

If you decide to switch disc brake pads from one material to another, use new discs that are compatible with the pad material to ensure optimum performance.

It is essential to add that you should use the correct disc brake pads for the entire braking system.

4. The disc brake is not embedded

Disc brakes can vibrate and make noise if they are not correctly seated.

Drop-in disc brakes are a must if you bought a new bike or installed new brake pads. This process transfers some pad material to the rotor, improving the fit between the pad and rotor and eliminating noise-causing vibrations.

To insert disc brake pads, find a quiet area and ride at a walking pace, then apply both brakes evenly until you almost come to a stop. Then release the brakes and repeat the process 10 to 15 times. As the cycle progresses, you will feel an increase in braking power.

When inserting the disc brake, be careful not to pull the brake lever too hard. This causes the brakes to stop the wheel from spinning, and the material does not transfer evenly from the pads to the rotor.

5. Pad wear

When your pads wear, noise can occur.

You can hear the metal rubbing disc rotors as the spacers wear down to the bare metal.

You can usually check the condition of the pads by looking at the back of the caliper or by removing the wheel and restricting the amount of pad material remaining.

Campagnolo disc brake pads have a visible wear indicator. They also sound an audible warning when they arrive.

When installing new disc brake pads, thoroughly clean the disc rotors and calipers to prevent old contaminants from entering the new places and for an optimal break-in process.

6. Brake disc or caliper not tightened properly

If your brake rotors or calipers are not tightened properly, you will often hear a metallic clanging sound. You may also find that the disc brake pads do not line up because the calipers or rotors are not securely seated.

Make sure the brake discs and calipers are correctly tightened. There is usually a torque indicator next to the component.

Centrelock rotors are typically tightened to around 40Nm using a snap ring tool.

To tighten the six-hole washer, it is best to use a star pattern. First, lightly tighten one screw, then move to the other screw and tighten it evenly. Next, pull the bolt next to the first bolt you started pulling evenly, tighten the opposite bolt, and so on.

7. Bent disc rotor

Bent disc rotors are a common cause of disc brake noise.

To avoid this problem, make sure not to lean the bike against the brake rotor. This might sound simple, but it’s easy to accidentally bend a disc rotor when loading a bike into the car, for example.

To secure a bent disc rotor, look carefully where the bend is in the rotor, then bend it back using a suitable rotor bending tool. Avoid excessive force as it is easy to turn the rotor too much in the other direction. It is also important not to touch the disc rotor with your fingers, as oils from your skin can contaminate it.

Some mechanics prefer to bend the rotor by hand. You put less force on the rotor than a unique tool. If you decide to do this, hold the disc rotor with a lint-free cloth to avoid contamination.

If your brake rotor is bent in multiple places, it’s unlikely to straighten it out – or just enough to avoid friction with the pads in the caliper. In this case, it is better to replace the rotor.

8. Heavy or crowded bleeding

If too much brake fluid is added during the venting process, this can cause the caliper pistons to move further forward, resulting in less clearance between the pads and disc and possible friction.

You can identify the problem by trying to push the piston back into the caliper bore using a special piston press or plastic tire lever. If the fluid is too full, you will have trouble moving the piston back into the caliper.

Use the correct caliper spacers when you bleed the brakes to avoid this problem.

Shimano and SRAM include caliper spacers in their bleeder kits, while Campagnolo sells an “oil level tool” that you can install in place of brake pads.

9. Poor frame coverage

The caliper must be centered on its stand to function optimally and avoid noise. If the frame is not adequately prepared at the factory, you will never be able to align the calipers properly.

You may also be unable to center the calipers in their mounts if there is excess paint around the mounting points when spraying the frame. If you suspect this is the case, your best bet is to take your stand to a bike shop, where there is a finishing tool that can remove excess material and adequately calibrate your calipers.

But keep in mind that some noise is unavoidable…
Unfortunately, the world we live in is far from perfect. Even if your brakes are optimally aligned, you can still hear the noise they make after you drive through water, sand, or mud and hit the pads.

Road disc brakes have much tighter tolerances than their mountain bike counterparts. There’s far less room for error, and sometimes, you can still notice some noise as hard as you can.

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