What Are Rotors On A Car?

Dustin Hawley | Feb 25, 2021

In order to drive your car safely, you have to have a reliable braking system. Modern vehicles use several components in conjunction with one another to successfully slow and stop moving cars, especially when they travel at high speeds.

car brakes and rotors

Brake rotors are some of the most essential components in braking systems. Let’s take a closer look at what rotors are, what they do, and the different types of rotors you can find if and when you need a replacement.

Rotors: In A Nutshell

Brake rotors in cars are circular metal discs connected to the wheels. There are four brake rotors installed in cars, one for each wheel. The rotors’ primary purpose is to slow down the turning of the car’s wheels by utilizing friction.

The brake rotor process occurs when calipers squeeze your car’s brake pads together. The pads rub against the rotors’ surface areas, creating friction and eventually slowing down wheel rotation and your vehicle’s overall speed.

What Are Rotors Used For?

Brake rotors are used alongside other braking components to slow and stop your vehicle. Without brake rotors, your vehicle would not be able to stop safely or slow down after acceleration, aside from gradual slowing due to friction with the air and the road itself.

Your vehicle also has brake pads that clamp down on your wheels to stop them from spinning. For context, the rotors are the surfaces those pads press down upon. They are typically made of iron, so they maintain long-term durability. But although they are durable by default, brake rotors still require maintenance and replacement from time to time.

How Do Brake Rotors Work?

Brake rotors begin working as soon as you step on your brake pedal. When you depress your brake pedal, the brake pads compress against the rotors. Keep in mind; there’s one rotor installed per wheel on your car. When you brake, all four wheels slow down in unison.

As the brake pads press down on the brake rotors, friction is applied, which progressively slows down the rotation of your car’s wheels (provided you are not still pressing down on the accelerator). The process of slowing your wheels through friction naturally creates intense heat.

Therefore, brake rotors are manufactured from steel to resist this heat. Brake rotors also typically have ribs or gaps to allow heat to dissipate efficiently during the braking process. Brake rotor types are differentiated by the kinds of ribs used in their designs.

After you lift your foot off of the brake pedal, the brake pads stop pressing down on the rotors and allow the car’s wheels to again move freely without obstruction.

Types Of Brake Rotors

There are several different types of brake rotors. It’s crucial to know these types so you can seek out and purchase the appropriate brake rotors for your vehicle when the time comes to replace them.

There are four primary types of brake rotors. You can either personally dismantle your braking system to check yourself or contact your car’s manufacturer to determine which rotor type is used with your vehicle.

Let’s review the four primary brake rotor types.

Blank & Smooth

Blank and smooth rotors are the most common rotor type for passenger vehicles, like most standard sedans. Blank rotors are both simplistic and affordable.

However, some manufacturer-specific blank rotors may be created from recycled steel. As a result, some blank and smooth rotors don’t perform as well or last as long as other rotor types.

Typically, the original equipment manufacturer or OEM rotors have a longer life because they have thicker internal fins, allowing them to cool the brake pads more efficiently as they are squeezed.

Drilled

Drilled rotors have a series of holes drilled in spiraling patterns across the surface. The holes assist with heat dissemination and allow dust and water to escape the rotor’s surface without clogging or damaging the overall braking system.

Drilled rotors are typically preferred by drivers who live in wet climates, as this design can assist with braking in inclement weather. However, drilled rotors don’t last for as long under high heat conditions, so they are not normally used with racing vehicles. 

Slotted

Slotted rotors have special slots positioned around the exterior rotor surface instead of holes. Slotted rotors are often used with heavy-duty trucks and heavy SUVs, as these larger and heavier vehicles typically require more stopping power. Slotted rotors are also preferred for individuals who use their cars to tow heavy loads frequently.

The slots draw extra air between the rotor surfaces and the brake pads used with them. As a result, the rotors experience better cooling and heat dissipation and less debris collection over time. But slotted rotors don’t last as long as other types and can wear down brake pads more quickly as well.

Drilled & Slotted

Drilled and slotted rotors combine both of the above heat dissipation and debris removal designs described above. They feature both drilled holes and slots set in spiral patterns around the outside of the brake rotor surface.

These brake rotors are usually used by high-performance vehicles. Sports cars are a good example. Such vehicles rely on top-tier cooling and heat dissipation to achieve their phenomenal performance. Furthermore, sports vehicles and their drivers can easily afford regular brake rotor replacement, which is a big concern with these components.

Replacing Brake Rotors

It’s a good idea to replace your rotors from time to time. Brake rotor replacement is a necessity since braking at all will, over time, wear down the steel surfaces of the rotors and the brake pads as well. As these components wear down, your braking responsiveness and reliability will also decrease, leading to dangers when driving.

Make brake rotor inspection a regular part of your yearly car maintenance. Or take a look at your brake rotors yourself from time to time. You’ll also likely feel when your rotors are starting to suffer in performance, as your braking will seem less responsive and immediate.

Average rotor replacement services usually cost between $400 and $500 depending on the rotor type, the vehicle involved, and how much work is needed. You can also purchase rotors for a little cheaper and do the maintenance yourself, but only if you have the experience. 

Summary

Brake rotors are important components in your car’s overall braking system. Be sure to pay attention to how they perform and how responsive your braking action is so you can replace them when necessary. Don’t hesitate to ask a mechanic which rotor type is best for your vehicle and driving habits when picking out new rotors.

Explore new car previews
2022 Ford Expedition Preview
2022 Ford Expedition Preview
The 2022 Ford Expedition comes in standard-length and extended-length body styles and in XL, STX, XLT, Limited, King Ranch, and Platinum trim levels. A new off-road-ready version of the SUV joins the lineup for 2022, and the returning Stealth Edition gains more power and performance.
Read the full review
2022 Honda Passport Preview
2022 Honda Passport Preview
There is no such thing as too many SUVs in an automaker’s lineup. So, to give its customers something to consider in between the popular CR-V and Pilot models, Honda resurrected the Passport nameplate a few years ago and glued it onto a Pilot-based midsize 5-passenger crossover SUV.
Read the full review
2022 Acura RDX Preview
2022 Acura RDX Preview
Acura currently sells five models, and the SUVs are the most popular. The midsize MDX gets a complete redesign for the 2022 model year, and now the automaker announces a substantial refresh for the compact 2022 Acura RDX.
Read the full review
Read all articles
Scroll to the top
New Car Preview
2023 Kia Sportage Preview
Most Dependable
2019 Vehicle Dependability: Most Dependable Small SUVs
Most Popular
10 Most Popular Luxury Cars
New Model Update
New for 2019: Buick
New Car Preview
2024 GMC Hummer EV SUV Preview
More related
articles