There is no doubt that disc brakes have been an undeniable breakthrough applied to the practice of road cycling
. Proof of this is that we do not know any cyclist who, after trying them, has gone back to rim brakes. But nothing is infallible. A large part of cyclists' complaints are caused by noise. That damned screech... We could say that noisy disc brakes top the list of annoying problems for most cyclists, both mountain
and road
.
The noise from disc brakes can be annoying and affect your experience when riding a bike. In addition to fixing these noises, it is important to make sure that the brakes are always in optimal condition. In fact, maintaining good brake performance requires periodic checkups. If you are wondering how often you should check your bike's brakes
, check our guide to make sure your brakes are always in perfect condition to guarantee safe riding.
Why do disc brakes make noise?
Many times, the noise is caused by moisture, rain, fog, or riding through puddles. In this case, there is no problem: the noise will disappear on its own. Another common noise is the metallic sound made by the disc brake after a long and steep descent. The cause is usually a temporary deformation caused by heat in the disc. When it cools down, the problem also disappears. Worn brake pads also cause a shrill noise, especially when the wear is complete and the metal backing plate rubs directly against the disc. In this case, the risk of damaging the disc also increases greatly. Another source of annoying squeaks is possible contamination of the pads and/or discs due to grease or dirt.
This could be due to any contaminant you might encounter on your route, such as loose grease on the asphalt. In other cases, it could be due to a brake fluid leak caused by worn piston seals. Therefore, the more kilometers you ride, the higher the chance of having problems in this regard. Another cause could be a failure in brake adjustment. If the pads and/or calipers are not properly aligned, they can cause vibrations that make noise. The same can happen if bolts and other components are not tightened correctly. The compound used to make the pads can also influence the noise in your bike's braking system. So-called organic pads tend to be quieter than metallic ones. If you decide to change to pads of a different material than the ones you already have installed, make sure the rotors are compatible with them to ensure optimal performance. Up to this point, the solution is simple. The problem comes when the annoying squeal persists over time. In the worst-case scenario, it could be caused by some kind of failure in the braking system. If we don't pay attention to it, the problem could end up putting our safety at risk.
How to fix noise in disc brakes?
Once the cause is detected, solving the problem is relatively simple. The first step is to properly clean the brake rotors and pads. For this, you should use a specific cleaner for disc brakes. Normally, this type of product is based on isopropyl alcohol (also known as isopropanol), which guarantees quick evaporation and leaves no residue. Apply a generous amount to the rotors using a clean cloth. Take the opportunity to check them for any warping or deformation. If so, perfect alignment of the parts will be impossible, braking will be much less effective, and the noise will persist. Although the rotors are made of steel, they are not designed to withstand any lateral force. They can bend easily if, for example, you accidentally rest the bike on one of them.
As for the brake pads, ideally you should remove them from their caliper, inspect them, and clean them properly. Pads with a shiny or glazed surface may be a sign of contaminated or excessively worn pads. At this point, they may squeal and will not function properly. Sometimes, heat can cause this effect. Lightly sanding the pads (with fine-grit sandpaper) so that their texture becomes a bit rougher would be enough for the system to work properly again. It is important to be careful when applying lubricant or degreaser to the drivetrain. Avoid aerosols, as it is easy to accidentally spray the braking system. Or, at the very least, protect the area properly. If the pads are contaminated with brake fluid or any lubricant, the best thing you can do is replace them as soon as possible, as it is difficult to fix. Performance will suffer, and the noise will increase.
The noise caused by contaminated brake pads is difficult to solve, so the best option is to replace them.
When removing the pads, you can take the opportunity to clean and inspect the caliper for signs of brake fluid leaks from the pistons or if the seals appear worn. If you notice any sign of leakage, it is best to go to your trusted mechanic. For proper operation, disc brakes must be correctly aligned. That is, the rotor must be centered between the brake pads so that both grip it at the same time and with the same force. This is particularly important in road disc brake systems, where the rotor has minimal clearance between the pads. To perform this task correctly, you can do the following: loosen the bolts that attach the caliper to the frame to allow it to move freely; spin the wheel and squeeze the brake; with the brake lever pressed, tighten the bolts making sure the caliper does not move. When you release the lever, the brake pads should be centered. If necessary, repeat the operation. Another task to keep in mind is aligning the rotors when mounting the wheel to avoid rubbing against the pads.
If your bike has a quick release, make sure the wheel is centered. The best way to do this is to tighten the wheel while the bike is on the ground. This allows gravity to help center the wheel. If your bike has thru-axles, this step is not necessary, as the wheel centers itself as it is tightened.
With these simple tips, the squealing of your disc brakes should disappear. If, even so, it persists, you may be facing more complex problems. The issue could lie in the connection points of the braking system with the frame. It could be due to an excess of material preventing proper centering, but that is a more remote possibility. Another cause could be incorrect bleeding of the hydraulic brakes. If the system is full of fluid, the pistons may not retract completely, which can cause constant rubbing with the rotor. Sometimes, it is even the pistons themselves that can cause friction and noise, in case of wear or lack of lubrication. In any case, and if in doubt, it is best to go to your trusted shop.
Tuvalum Team
