When To Replace Brake Rotors

The brake system is crucial to a car’s safety. The master cylinder, brake rotors, brake pads, brake calipers, brake booster, and brake pedals are all components of the brake system. Like every other component, the brake rotor is an important part of the system. It is larger and weighs more than any other component. It is susceptible to wearing and needs replacement.

However, unlike the brake pads that are easily noticed and replaced when worn, brake rotors are rarely cared for. Oftentimes the brake rotor wear is ignored which is bad for safety. Hence today we will be considering when you should replace your brake rotor. We will also answer other likely questions you may have on brake rotors.

What Are Brake Rotors

A brake rotor is a unit of the car brake system. It is a large disc made of carbon-ceramic or steel found on each side of your car’s axle. As your vehicle sets on motion the brake rotors turn along with the car wheel. The brake pad helps the brake rotor function when pressure is applied to the braking system. It is the brake pad that pins down the brake rotor to put the car to a halt.

How Do You Know Your Brake Rotor Needs A Replacement

Unlike your brake pad, the need for your car brake rotor to be changed is not always evident. This may be because brake rotors take longer to wear. However, a definite way to know your brake rotor needs a substitute is by its diminished thickness. The car service book is a source of knowing this. It tells you the least the thickness of the car brake rotor should be, sometimes it’s written on its surface.

Furthermore, the following signs may imply your brake rotor needs a change;

1. The feel of vibration from the steering wheel or the brake pad or both when pressure is applied on the brake pedal: It’s normal to feel a short shudder on the brake pedal when the anti-brake system activates. Aside from this applying pressure on your brakes should not cause vibration if the brake rotor stops in less than 0.13mm. If the brake rotor runout period exceeds this there will vibration from the brake pedal and steering wheel. 

Though this isn’t a definite sign for brake rotor replacement, it may still indicate there’s a problem with the brake system. A cause of the vibration is associated with the collection of pad deposits on the brake rotor surface. These pad deposits may be removed by a bed process or by a rotor replacement if the process doesn’t work. The proper choice of formulation usage on your brake pad can prevent pad deposits in the first place. Additionally, the vibration may also be from a bad suspension.

2. Production of loud noise when pressure is applied on brakes: When the brake components are rusted or worn there is more friction between them. This gives off a grinding sound when the brake is applied. For most brake pads there is a metal clip within them. It is a mechanical wear sensor. This metal grinds against the rotor and produces a noise when the brake pad becomes thin. 

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This system works to draw the driver’s attention to the brakes. Although it is more significant to the brake pad, it can also bring your attention to your brake rotors.

3. Presence of cracks on the surface of the brake rotor: The presence of cracks on the brake rotor is usually associated with excessive heat. This causes the brake rotor to expand and shrink simultaneously. Cracks on the brake rotor are of two kinds and each presents differently. Although both are a result of excess heat.

First is the heat checking. This state causes the development of tiny fractures on the rough surface of the rotor. It arises when the vehicle is on high speed and high heat. This heat checking is an expected reaction on the brake rotor. At this state, the brake rotor may not need a replacement just yet.

Next is a crack to the edge. Those tiny fractures on the rotor’s surface may expand and find there a way to the edge of the brake rotor. If the crack gets to the rotor’s edge on either surface then there is an urgent need for a replacement. This is because the brake rotor is no longer in a good state.

You should know that a brake rotor of premium quality lasts longer when faced with either crack. However, you should also know that cracks are not a result of low-quality brake rotors.

4. Bad condition of the brake rotor surface: The presence of debris and the wearing of the brake rotor can leave the working surface damaged. If the wear is extreme the rotor can be destroyed by its friction with the metal backing plate. Also, the accumulation of debris and rust between the brake rotor and pad can cause damage to the rotor’s surface. When you see the rotor’s surface is in a bad state, that’s an indication that a replacement is needed.

5. Below minimum thickness of the brake rotor: When the brake rotor becomes thin and exceeds its minimum thickness, then is a need for substitution. This is to maintain the safety of the vehicle and its passengers. Measurement of the thickness can be done with a brake rotor micrometer. Then you can compare the result with the value in your car service manual.

Other Signs Include;

A pseudo-warped brake rotor: When rusts, stones, or other fragments sit on the wheel hub they may alter the placement of the brake rotor. Thus giving the rotor a warped appearance. Proper cleaning of the wheel hub, the brake rotor, and its mounting surface should help solve this.

Loose hub and brake rotor: When the installation is not properly done, there may be a miss in the tightening sequence. This may cause pulsations and vibrations of the brake rotors. Proper tightening by a professional should solve this.

Brake rotors are vital to maintaining the safety of a vehicle. Therefore, you should pay good attention to them. A bad brake rotor should not be managed by replacing it accordingly.

How Long Do Brake Rotors Last

Steel brake rotors should last about 60,000 to 70,000 miles and carbon-ceramic rotors a car’s lifetime. However, this is subjected to variation based on some factors. The durability of brake rotors is based on you, the driver, your vehicle, and the rotors. How you drive influences how long your brake rotors will last. 

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If you are always on high speed your rotors work harder and can wear faster. The weight of your car also plays a role in the rotor’s durability. Heavy vehicles put more work on their brakes when trying to come to halt. This work in turn tells on the brake rotor. Also, a good quality brake rotor is more durable.

What Causes A Bad Brake Rotor

Oftentimes, a bad brake rotor is a direct result of how you drive and hit on the brakes. The wear may be from regular sudden stops especially when on high speed. When pressure is suddenly applied on the brakes heat is generated from the grinding of the brake pad and the rotor. This heat if regular can cause the rotor to wear. 

Also, a worn brake pad can damage the brake rotor. This is because as the pad thins out, its metal is exposed. Then the collision of the rotor and the metal pad can result in cracks on the rotor.

Can You Drive With A Bad Brake Rotor?

No, you should not drive with a bad brake rotor. It is neither safe for you nor the people around you. If your brake rotors present with signs of a failure or you know it is bad then you shouldn’t drive it. Instead, you should contact an automobile mechanic to have it checked and replaced immediately. Driving impedes the efficacy of the entire brake system. Thus driving such is a big risk.

What Is The Cost Of Replacing A Brake Rotor?

On average the price of a brake rotor per axle is between 200 and 400 dollars. Labor usually costs about 150 dollars. Hence, for a brake rotor replacement, you may be spending about 300 to 600 dollars. However, this price is dependent on your vehicle’s model. A rotor replacement for a racing car costs more than a regular car.

Do You Replace Brake Rotors Each Time Brake Pads Are Replaced?

Brake pads wear sooner than brake rotors. If your rotors are still in a good state you don’t have to change them. This is because rotors are generally made to last longer than pads. Not less than 60,000 miles for steel rotors and longer for carbon-ceramic rotors. However, when changing your brake pads thoroughly check your brake rotors and be sure they are in a good state. But when you change your brake rotor you should also change your brake pad and inspect your tires. 

What Happens When You Do Not Change A Bad Rotor?

A major consequence is the failure of the anti-lock brake system. When this occurs you are in danger of driving the vehicle.


Brake rotors are part of the car brake system and they don’t wear easily. However when they do you should replace them immediately to maintain safety.