Your bike’s brakes are the most important component for riding safely and roasting the pavement with confidence.
As important as it is to understand how your brake system works, it’s equally important to know what to expect if something goes wrong.
Vibrating brakes is one sign that something is wrong and we’ll tell you why.
Here Is the Answer to Why Motorcycle Brakes Vibrate When Applied:
If you are experiencing vibration from your bike when you apply the brakes, there is something interfering with the contact between your brake pads and your rotors, such as a warped rotor. This usually occurs from excessive heat or wear in your braking system.
Why Does the Warped Rotor Cause Vibration?
Braking vibration happens when something is interfering with the contact between your rotor and brake pads. Your calipers and brake pads depend on the rotor to be clean and flat to work properly.
If your rotors have developed a high spot, it is usually referred to as a warped rotor. When the calipers try to squeeze the brake pads onto the warped rotor, a push back effect occurs.
In a previous article, we discussed how each component of the brake system work together to bring your bike to a stop.
Brake fluid exerts pressure on the calipers when you squeeze the brake lever. This then puts pressure on the brake pads and friction is applied to the rotors from the brake pads, helping your bike to stop.
When the rotor is warped, the bumps formed push back on the braking components, causing a vibration sensation as the braking system continues to try to engage.
Also read our article about how to tell if motorcycle has bad brakes.
What Causes Warped Brake Rotors?
Here are the major causes of warmed motorcycle brake rotors:
1. Excessive Heat
Warped rotors are most often caused by excessive wear or heat. Basic chemistry tells us that when metal is heated, it softens.
Each time you apply your brakes, you are putting them under heat. It’s not uncommon for racers and aggressive riders to experience warped rotors more often than a newbie or an average rider.
The aggressive riders are riding faster and braking harder, thus putting more stress and heat on the brakes. This increases their chances of creating high spots on the rotors.
Excessive heat can not only cause high spots but also glazing (and we are not talking about the donut kind).
This glazing happens when brakes get too hot and the material from your brake pads melts and leaves a glazy film over the brake pads.
The glaze is slippery and requires more pressure and friction to build the correct amount of pressure for the brakes to work.
It’s similar to the way you would skid across ice or a slick road if you were trying to stop in your car. The same way your tires wouldn’t have the proper traction to stop, the brake pads won’t have the proper traction to make contact with the rotors, making it difficult to stop the bike.
2. Low Brake Pads
Letting your brake pads get low can also cause warping in the rotors. If the pads wear down too low, it will take more force, pressure and heat to get the bike to slow down and stop.
In more severe cases of ignoring low brake pads, the metal on the pads can become too thin and lead to metal-on-metal grinding that can quickly damage your rotors and leave them with an uneven surface.
3. Dirty Rotors
Salt and moisture are the perfect formula for rust, and both can do damage to any metal object, be it a building, car or bike.
Rust can quickly form from salt deposits and moisture if you don’t clean the metal immediately after exposure to a corrosive substance.
So, it’s important to clean your bike and dry it properly if you live near the coast or have driven through salt.
This may not cause the rotor to warp in the same way as heat, but it can deform the rotor and cause the same type of braking vibration of a warped rotor. The same can be said if the rotor is covered with excessive dirt, sand, or mud.
Even if you do everything right, depending on the age of your bike, your rotors can still warp.
Every time you use the brakes, you generate heat that slowly wears down the brake components. This is more likely to happen to riders who put a lot of miles on their bike than weekend warriors or commuters.
Can Warped Rotors Cause More Damage to the Bike?
Warped rotors can do significant damage to your bike if not addressed quickly. It can prevent other brake components from functioning properly, causing damage to them.
Not replacing your rotors can lead to unevenly worn brake pads (which will damage new rotors) and damage to your calipers as well. In the most extreme cases, you may even experience a steering wobble.
Warped rotors can affect your braking performance negatively. Not only will you feel an uncomfortable vibration, but your brake time can increase.
Worse of all, you could lose control of braking and the bike, causing a crash.
Please also read our article about how to fix a faulty motorcycle clutch.
How Do I Prevent Warped Rotors?
The good news is that there are several simple things you can do to prolong the life and integrity of your brakes. Here are ways to prevent your brake rotors from getting warped:
- Keep up with maintenance. It may seem tedious to inspect tires, air pressure, chains, and brakes regularly, but taking an extra minute to look over these things will not just save you money, but also your wellbeing.
- Inspect brake pads and brake fluid to ensure they are at proper levels. Doing this can ensure you are not pressuring your brakes unnecessarily and thus keep them in peak condition for longer periods.
- Wash and dry your bike. Keeping your bike clean will help prevent rusting and contaminants from warping your rotors.
- Learn about how your brake system works. If you become familiar with the brake components and how they work, you will be more likely to notice when something is amiss.
- Avoid excessive braking. Dragging your brakes, or keeping the brakes hot will put high stress on your brakes and cause them to wear faster.
- Stay alert while riding and give yourself plenty of space to stop. Doing this ensures you’re not grabbing a fist full of brakes to stop your bike. Keep your foot off the rear brake lever when cruising to avoid dragging, and only let your finger float on the front brake lever. This will ease stress on the lever but still allow you easy access to brake in emergencies.
Make sure to also read our article about why motorcycles die when put in gear.
What Should I Do If My Rotors Are Already Warped?
Unfortunately, resurfacing rotors is not an option for motorcycles.
Resurfacing is a common practice in the automotive industry where a small amount of the surface is shaved off, creating a new, even surface on the rotor.
However, motorcycle rotors and car rotors have different designs. Motorcycle rotors are made with drilled holes that make the rotor lighter while also dissipating large amounts of heat. Because of these holes, the tool used to resurface automotive rotors would break if you tried to use it on this type of rotor.
If you are experiencing brake vibrations, it is best to take the bike to your trusted motorcycle mechanic and have them replace your rotors and pads before the damage gets worse.
Your brakes can serve as your last line of defense when you’re on the road. If your brakes ever feel off, take the time to inspect them.
Vibration is not a symptom to be ignored. As we’ve explained, it can not just be a sign of danger, but also rack up a hefty repair fee.