The braking system is one of the most critical systems in any motor vehicle. And two of its most crucial components are the brake pads and brake rotors. It’s pretty easy to confuse the traits and functions of these two components, but understanding them is quite essential.
Brake rotors attach to each wheel of your car and turn together with them. Each rotor has a flat surface that brake pads can press against to generate friction and convert kinetic energy to heat. Doing so will reduce the wheel’s turning speed and slow down the vehicle as a whole. The brake pads are attached to calipers and move based on your input through the brake pedal.
Read through this guide to learn much more about brake rotors and brake pads, the types that exist, and how they work together.
What Are Brake Rotors?
Brake rotors are flat, solid disks bolted to each of your car’s wheels. That attachment means that rotors turn along with your wheels at the same speed.
The purpose of each rotor is to provide the brake pads with a perfectly flat surface to press against whenever you apply the brakes. Doing so will generate plenty of friction on the rotor’s surface, thereby converting the kinetic energy from the wheels to heat.
As a result, your vehicle’s wheels will slow down and eventually come to a complete halt. That process of slowing down will happen in proportion to how far you’re pushing down on the brake pedal with your foot inside the car.
It’s not hard to imagine that brakes get applied dozens, if not hundreds, of times daily. So, the brake rotor must be solid enough to withstand the pressure put on it by the brake pads without wearing out or warping too quickly.
Brake rotors come in plenty of different types. They’re differentiated by the patterns on the rotor’s surface and the materials they’re made of.
So, in terms of patterns, these are the types of brake rotors you can find on the market today:
- Blank and smooth: Blank and smooth brake rotors are the most common kind, and you’ll find them on most everyday vehicles. As mentioned earlier, they provide a smooth metal surface without any designs for brake pads to press against and create friction. Doing that slows the wheel and reduces the vehicle’s speed.
- Drilled: These brake rotors have plenty of holes drilled into their surface. The holes help dirt, water, and heat move away from the rotor’s surface so they don’t interfere with the braking process. Drilled rotors are better suited for cars in wetter environments.
- Slotted: Some rotors have slots cut out of their surfaces instead of drilled holes. The slots allow more air to move between the brake pad and the rotor surface to carry heat away more effectively. So, these are ideal for heavy-duty vehicles whose brakes are prone to overheating, like trucks that haul cargo.
- Drilled and slotted: Lastly, you can find brake rotors that have both slots and drilled holes. These are often used in high-performance vehicles that need the combined benefits of both drilled and slotted rotors.
The surface designs on brake rotors aren’t the only differentiating factor they have. The materials they’re made from also matter, such as the following:
- Cast iron: Most brake rotors are made from good, old-fashioned cast iron. The material is solid and durable, but it’s also the heaviest. So, it’s not ideal for vehicles where weight is a concern, like race cars.
- Steel: Race cars or those that need to be light and fast work better with steel rotors instead. These are lighter and dissipate heat effectively, though they’re not as durable as steel.
- Layered steel: As the name suggests, these rotors are made using several layers of steel. The layering makes them more long-lasting, though they’re too costly for standard passenger cars. So, these are mostly used in the motorsports realm.
- Aluminum: Of course, aluminum is an option as well. The material is lighter and dissipates heat very well, but it also has a lower melting point. Those traits make aluminum rotors best for motorcycles.
- High carbon: High carbon rotors are made from iron, though they have a higher carbon content inside. They’re expensive, but they can handle a lot of punishment without cracking.
- Ceramic: Ceramic is a high-end material reserved for supercars and the like. It’s the most expensive material because it handles heat the best and lasts longer than others on the list.
What Are Brake Pads?
Brake pads are the other half of the braking equation, working alongside the brake rotors described above.
While brake rotors provide the surface on which to generate friction and slow the vehicle down, the brake pads are the components that actually create that friction. The pads press on the rotor and lose a tiny bit of their material each time to convert kinetic energy to heat and slow the rotor down.
Shape-wise, brake pads are all alike. What sets them apart is the material they’re made of, which includes the following:
- Semi-metallic: The most common kind, mixing 30%-65% metal with other materials like copper and steel wool.
- Ceramic: The costliest brake pad material typically used in high-performance vehicles for its braking power and ability to withstand lots of punishment.
- Low-metallic, non-asbestos organic (NAO): These contain less metal and can effectively dissipate heat. They are, however, noisier than the other options above.
- Non-asbestos organic (NAO): These are mostly made of organic materials that are softer and quieter. Unfortunately, they wear out faster, making them less ideal for regular daily driving.
Brake Pads Vs Rotors; What Are The Differences?
A brake pad and a brake rotor are two components forming part of the braking system. They work together, so it’s not a question of choosing one over the other. Instead, the focus is on matching the best brake pads and rotors for your individual needs.
So, to sum up everything described above, here’s a quick list of differences between brake pads and brake rotors:
- Purpose: Brake rotors provide a flat surface that brake pads can press against to generate friction and convert kinetic energy to heat, thereby slowing the vehicle down.
- Attachments: Brake rotors are attached to the car’s wheel, while brake pads are attached to calipers.
- Materials: Brake pads and rotors are made from various materials, each with advantages in terms of weight, heat dissipation, and durability.
- Mechanics: Brake rotors spin together with the car’s wheels. Meanwhile, brake pads are pushed against the rotors by calipers whenever the driver presses on the brake pedal.
Again, brake pedals and brake rotors have clear differences. Still, it’s important to remember that the two components work together to achieve the same goal, which is to slow the vehicle down by reducing the wheels’ turning speed.
As mentioned earlier, brake pads and rotors work together, and one cannot function without the other.
That’s also why these two brake components are typically maintained together. Both components must be kept in excellent working condition to ensure that they can slow the wheels down when the brakes are applied.
Brake rotors and brake pads must be replaced when they wear out to ensure that the vehicle can brake effectively. That way, as the driver, you can maintain complete control over the car and avoid dangers on the road, thereby preventing collisions.