What Are Brake Rotors? 4 Signs of Bad Brake Rotors vs Bad Tires

Why is a tire seller talking about brakes? While brake rotors and tires don’t physically touch, their performance is deeply interconnected. It’s like wearing a good pair of shoes versus worn-out soles: Better shoes protect your knees, hips and back the same way that good brake rotors protect your vehicle’s parts, including tires.

Good tires with proper tread provide the necessary grip for effective braking. If brake rotors are uneven or faulty, they can cause uneven pressure on the tires, leading to irregular wear patterns and reduced safety.

Relatedly, the signs of bad brakes, worn out rotors and bad tires are similar — diagnosing the problem may be confusing to most of us, who aren’t trained mechanics!

Read on to learn how brake rotors work, when you should replace them, and how you can check to see if your brake rotors are in good condition.

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First, What Do Brake Rotors Do?

Related to brake pads, brake rotors are an essential part of your vehicle’s braking mechanism that you interact with every time you drive. Any time you press your brake pedal, your vehicle’s braking system clamps the brake pads on the brake rotor to slow, or stop, the wheels of your vehicle. The brake rotor, sometimes also called the “brake disc” is found behind the wheel of your car; it’s what a wheel is attached to by the wheel studs. 

Brake rotors are flat, smooth wheels that easily dissipate heat when the brake pads are squeezed against them. The friction between the rotor and the brake pad is what makes your vehicle slow down and stop moving. Because brake pads are directly attached to the brake rotor, properly functioning brake rotors as essential to your vehicle’s function. 

How long do brakes and rotors last? Brake rotors wear down over time, although not as fast as brake pads. 

How Do Brake Rotors Work?

If you’ve ever ridden a bicycle, you’ve seen a simple version of how automobile brakes work. When you press (or squeeze) the brake lever on a bike, a rubber clamp grips the outside of the bike wheel. The same principles of this system apply to vehicles, with the main difference being how fast (and how much heavier) a car is compared to a bike. Rather than a rubber clamp, your vehicle uses a sturdy brake pad that’s designed to handle a lot more force.

Because of the extra mass and speed that cars have, early automobile manufacturers developed a system where the brake rotor would act as a buffer between the wheel and the braking system. Clamping down on the wheel itself could inflict a lot of damage on the wheel and would make you have to replace the wheel more often. Wheels are also usually made of softer metal alloys so that they’re lightweight and well-balanced. 

The brake rotor is typically made of hard, heavy cast iron. But occasionally, you’ll see steel, aluminum, ceramic, or carbon with luxury vehicles. These don’t significantly improve the standard braking function of the vehicle, rather being affordances for edge cases such as driving very fast and suddenly braking, putting a lot of stress on the rotor. Cast iron is a simple solution for most vehicles because it’s sturdy and resistant to heat that’s generated from the brake pads. 

As your vehicle moves and the wheel spins, the brake rotors spin with your wheel. Your brake pads are mounted directly on top of the rotor and will clamp down when you apply the brakes. This friction causes the brake rotor to stop spinning and your car to slow. However, heat will also be generated. Brake rotors usually have a vented design, so the heat is more efficiently dissipated. The different venting designs that brake rotors have dissipates heat differently. 

When Should I Replace My Brake Rotors?

Although you don’t have to replace brake rotors as often as brake pads, they do wear down over time as brake pads repeatedly clamp against their surface. That said, most brake pads have indicators on them to see when you should replace them. Brake rotors do not. 

The lifetime of a brake rotor is much higher than a brake pad; typically around 50,000 to 70,000 miles. You can check with your mechanic, auto dealer or the manufacturer of your brake rotors to get a more accurate mileage measurement. But this depends on what conditions you drive your vehicle in and how you drive. 

But, once a brake pad is worn down, it needs to be replaced very soon, as it can do serious damage to your brake system and even prevent your vehicle from braking properly when in motion.

4 signs of bad brake rotors vs bad tires

Here are some signs that you need to replace your brake rotors:

• A pulsing motion when you brake
• Abrasive screeching or squealing noises when you brake
• Longer stopping distances when you brake
• A grinding feeling when you press down on the brakes

Because most brake rotors are iron, they can corrode or warp over time, especially if you drive in wet or snowy conditions where there’s a lot of salt on the road to melt the ice. 

If you’re noticing issues with your vehicle’s braking or just want to check the status of your brake rotors, it’s fairly easy to inspect them yourself. 

How Do I Check My Brake Rotors?

Before checking any vehicle, make sure the motor is off, the vehicle is in park, and, if needed, the safety brake is on. Even better, take your vehicle to a qualified mechanic, who can inspect your brakes and rotors for you; this article will help you understand the right questions to ask!

1. Wait for the vehicle to cool: Make sure you haven’t driven, and your vehicle has been stationary for 30 minutes or so. Brake rotors can get very hot, so you don’t want to inspect them after you’ve driven and burn yourself. 
2. Locate the rotor: Grab a flashlight. Get close to your wheel and look inside of it. In between the spokes of your wheel, you’ll see a flat, smooth disk on the inside of your wheel. You may need a flashlight to see it.
3. Look for:
   • Cracks
   • Grooves
   • Warping or variations in the rotor shape
   • How thick the rotor is (you may need to look at it from the side to see this)

If you’re concerned about your brake rotors being warped, most mechanics have specialized measuring tools used to check if there are any distortions in the shape of the rotor. They can also take your wheel off to get closer to the rotor to measure the thickness of the rotor. 

If your brake rotors are fine and your vehicle is still vibrating or jittering when you brake, it may be a sign that your wheels are misaligned or your tires aren’t balanced.

It could also be a sign that your brake pads need to be replaced. Remember that brake pads are the most common point of failure for the brake system, as they experience the most strain from daily use. 

Investing in high-quality brake rotors ensures smoother, more predictable braking, which helps preserve tire tread life and enhances overall safety. Conversely, poor-quality or failing rotors can lead to uneven tire wear, reduced tire lifespan, and compromised vehicle handling.

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main image ID 147964875 | Peerapat Tharawiwat | Dreamstime.com

old brake rotor ID 327894304 | Wodthikorn Phutthasachathum | Dreamstime.com