What Are Rotors On a Car—And Why Do They Fail?

What are rotors on a car, and why do you need to replace them? Driving with worn brake rotors is extremely dangerous: here’s why.
Written by R.E. Fulton
Reviewed by Melanie Reiff
background
Brake rotors are metal discs that slow your wheels down by creating friction with brake pads. They’re essential to stopping your car—and they can wear out faster if you brake too hard
Car insurance
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Jerry
is here to break down everything you need to know about this essential braking system component. We’ll show you how to reduce wear and tear on your rotors, go over the average cost of a replacement, and throw in some tips for reducing your car insurance costs with our
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What are rotors on a car?

Most modern cars are equipped with a disc brake system, which pairs metal discs or rotors with brake pads operated by calipers. When you press down on your car’s brake pedal, the calipers squeeze brake pads made of semi-metallic material against the brake rotor, usually made of iron or steel. The friction slows down your car’s wheels, stopping the car. 
Every wheel in a disc braking system has one brake rotor and two brake pads. If your car uses only disc brakes, it should have four rotors and eight pads, but some older vehicles mix disc brakes with more traditional drum brakes, often pairing rotors and pads in the front with a set of drum brakes on the rear wheels. 

Types of brake rotors

Any braking system relies on friction to slow down the wheels—and friction creates heat. This means that your car’s rotors need to stand up not only to repeated friction from the brake pads, but also to high heat.
Because of this, most brake rotors are made of iron or steel. However, high-performance vehicles may have more expensive rotors made of high-carbon iron or ceramic
In addition to this heat-resistant material, some rotors have drilled holes or grooves in their surface to help distribute and dissipate that thermal energy more efficiently. Drilled rotors are ideal for rainy climates, while slotted rotors work well for heavy-duty trucks and SUVs that have to tow hefty loads. High-performance vehicles like sports cars often have both holes and slots in the surface of the rotors.
Unless you own a high-performance vehicle or have chosen to swap out your factory rotors for a new set, your OEM rotors are likely blank and smooth. Blank rotors are the most common type of brake rotor, especially for sedans. 
The table below takes a closer look at how each type of rotor can affect braking performance.
Type of rotor
Benefits
Downsides
Ideal for
Smooth rotors
Long lasting, cost-effective, quiet
Not enough ventilation for heavy-duty trucks
Most vehicles
Drilled rotors
Greater friction, better drainage
Can’t stand up to excessive heat or high speeds
Street vehicles, wet climates
Slotted rotors
Improved stopping power
Noisy, short life span
Trucks and SUVs, off-road vehicles
Drilled and slotted rotors
Improved braking at high speeds
Short life span
High-performance vehicles
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Are rotors and brakes the same?

No—the term “brakes” refers broadly to the entire braking system, from brake calipers to brake lines and pads. Rotors are a crucial component of that system, but the two terms aren’t interchangeable. 

Common causes of brake rotor wear

Ideally, your brake rotors should last between 50,000 and 70,000 miles. But they’re certain to wear out eventually—after all, the way brake rotors work is designed to cause wear. 
While you’ll need a rotor replacement eventually, there are a few common things that can cause these critical brake components to wear out faster. These include: 
  • Harsh braking: If you slam on the brakes, especially at high speeds, you create more friction between the pads and the rotor. Friction is the point, but the less you can use, the longer your rotors will last. 
  • Riding the brake: On a similar note, frequent repeated braking adds to the stress on your rotors. 
  • Failure to replace brake pads: Brake pads wear out much faster than rotors, and when they’re worn down, you’re left with raw metal scraping against your poor rotors, which can cause grooves and scratches. 

Tips to help with rotor wear

You may not be able to put off a
brake rotor replacement
forever—but there are plenty of ways to extend the life of your rotors! Work on developing these driving habits to protect your rotors from unnecessary wear and tear. 
  • Keep your speed in check: We know, you’ve got places to be, and who doesn’t love the thrill of high speeds? But the faster you drive, the more you’ve got to brake to come to a stop. 
  • Embrace the coast: Easing up on the gas makes it easier to coast to a stop instead of braking hard—which will reduce the wear on your brakes! 
  • Lighten up: The more weight your car carries, the harder your brakes have to work to bring it to a stop. Avoid toting more cargo than you need to. 
  • Don’t miss a flush:
    Your brake fluid should be flushed
    every two years or so to maintain optimal performance of the entire braking system.  
  • Learn the three-second rule: Keeping a safe driving distance (e.g. three seconds of space between you and the vehicle in front of you) will reduce your need to brake suddenly. 
MORE: How to check and add brake fluid
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How to know when it’s time to replace your brake rotors

How do you know when time’s up for your rotors? Including regular brake inspections in your
car maintenance schedule
can help you stay on top of caring for this part, but looking out for these telltale warning signs can help you know when it’s time to install new rotors. 
Squealing is the classic sign of worn or warped rotors. You might call the noise squeaking or
grinding
, but the story is the same: your rotors are worn out and need to be replaced. Along with that shrill sound, you might notice the brake pedal vibrating or shaking at longer stopping distances
If you notice any of these red flags, get your car to a mechanic immediately. Replacing brake rotors can be costly (more on that in a moment), but putting off this service could result in a total failure of your braking system. Driving with worn brake rotors is extremely dangerous and could cost you thousands in vehicle repairs and medical costs. 

Cost to replace brake rotors

So how much will you pay to swap out your worn rotors? It depends. On average, the cost of a new set of brake rotors ranges from $150 to $500—but your costs could be higher or lower depending on: 
  • The make, model, and age of your car
  • The cost of labor in the area where you live
  • How many rotors you’re replacing
  • Whether you
    replace the brake pads
    at the same time
Brake rotors are always replaced in pairs: you can’t replace a single rotor without replacing the other rotor on the same axle. Your brake rotor replacement will involve new rotors for both front brakes or both rear brakes—or for all four! 

How to save on car insurance costs

Replacing your brake rotors can be expensive, but it’s an essential service. One way to ease the blow of that repair bill is to shop for a new car insurance policy. With
Jerry
, drivers can lower their annual insurance costs by an average of $800+! 
Here’s how it works: when you download the Jerry app, you’ll answer a few basic questions about yourself, your car, and your driving history. Using that information (which stays private between you and Jerry), Jerry will search for customized real-time
car insurance
quotes from a pool of over 55 top providers.
If you find a lower quote in the app, Jerry’s team of insurance experts will handle all the paperwork to get you switched over as quickly as possible. 
The whole shopping process takes just 45 seconds—and it could save you enough money to offset the cost of new rotors! This is why Jerry is the
top-rated insurance app
with a 4.7-star rating in Google Play and the Apple App store.
“I thought my previous insurance rate was fair given the model of car I drive, but after
Jerry
gave me quotes, I realized I could pay only $84 a month for the same coverage through Plymouth Rock. I plan to shop for auto insurance through Jerry from now on!” —Jill I.
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