Brake Performance Blogs

When you step on your brake pedal, it forces the small piston(s) inside your brake caliper to compress, squeezing your brake rotors and essentially slowing down your car. Although this is the simplest way to explain the concept, it doesn't factor in some of the details that allow this to happen. Because the brake pedal doesn't just magically connect to all four brake rotors, it relies on the use of brake lines to divert your single force acting on the brake pedal onto the four corners of the car. These lines are filled with a hydraulic fluid we call brake fluid.

Brake fluid works well because it's a non-compressible, hygroscopic fluid which allows all the energy that your foot releases onto your brake pedal to be converted into braking pressure that squeezes your brake rotors and slows them down. So why is brake fluid so vital, yet often overlooked when shopping for brake rotors?

When you apply your brakes it causes your brake pistons to compress and clamp the brake rotors. This friction creates heat, lots of it. This means your brake fluid needs to retain its incompressible nature without boiling or evaporating due to the temperature.

What happens when your brake fluid boils or overheats? It creates air bubbles in the system and air is compressible opposed to brake fluid. So in turn, when you press down on the brake pedal, instead of clamping the rotors and slowing down the car, the brake fluid compresses the air and the brakes are not doing their job. This also translates to the driver as a mushy or unresponsive feeling brake pedal.

It's important to measure your brake rotor wear every 10,000 miles or at the very least every time you change your brake pads. You want to use a micro measuring caliper to determine your brake rotor thickness. For example, a new brake rotor with a thickness of 10mm is required to be replaced or turned at 9mm, meaning that your naked eye has to detect 1mm of rotor wear. Kinda impossible.

In order to get an accurate measurement for the amount of brake rotor wear we depend on our trusty micrometer. Prepare your car so you can remove the wheel.

With the wheel removed, you will have clear access to the rotor for you to make accurate measurements. There are several types of micrometers and measuring calipers so you want to make sure your caliper can measure to the tenth of a millimeter.

Next, you simply measure the thickness in at least three different spots of the brake rotor. Make sure to write down your measurements and you may get a few small variations. It helps to get at least 4-5 different measurements and to take the average of that.

Next, take a look at the brake rotor center hat. This is the portion that doesn't get exposed to the brake pad. You will normally find your minimum rotor thickness stamped there. It may be faint, but it's usually there. In some cases it may be located on the outer edge of the rotor.

Tip: Keep in mind that you want to avoid measuring too close to the inside/outside of the rotor, as the actual brake pad doesn't contact those edges. Also, for slotted rotors stay away from measuring the slots, as those will skew the results. Same goes with dimpled/cross-drilled rotors. Keep clear of measuring the holes.

Measuring Rotor Thickness

It's impossible to tell how much life is left on the brake rotors by simply looking at it. As a matter of fact, it's dangerously misleading! By simply looking at brake rotors, most rotors seem to be wearing fine unless there are cracks or huge chunks missing.
However, that is where the huge misconception lies.
Unlike brake pads, which show how much pad is left and have warning sensors, brake rotors have no such indicators. It's important for the safety and performance of your car to inspect these properly. We recommend inspecting your brake rotors every 10,000 miles to make sure they are within specs.
Follow our visual guide on how to inspect your brake rotors in just 6 steps. Make sure your rotors are cool prior to inspecting.
Note: If you observe any one of these 6 symptoms, it's recommended that you replace your brake rotors.

1. Visible Cracks
One of the most obvious ways to check when your rotors need to be replaced is through visible cracks. If you see a crack, it's time to replace your rotor. However, in certain cases small hairline cracks are normal if you race your car, such as track days and timed performance events. Keep in mind if you don't know the difference, it's better to be safe than sorry.

2. Grooves
 If you have an open-spoke wheel design, you can run your finger vertically down the brake rotor friction surface. If you can feel and see noticeable grooves, then it's time for new brake rotors.
For cars with hub caps that don't expose the rotor, you will need to remove your wheel to inspect your brake rotors.

3. Rotor Edge Lip
On worn brake rotors, if you follow the rotor to the edge you can usually feel/see a noticeable lip. This lip is created as the brake pads normally don't contact all of the rotor surface and therefore leaves an outer lip when the rotors are worn down.
Keep in mind that rotors reach their wear limit at only about 1mm. If there is an obvious lip, it's most likely near its wear limit or is wearing unevenly. Measure with calipers to double-check.

4. Heat Spots
Heat spots (Fig. x) are a telltale sign that your brake rotors have uneven brake pad deposits. How do they affect you? Heat spots will lead to brake harshness, vibration, and reduced structural integrity. Heat spots on brake rotors occur when brakes aren't broken in (bedded) properly and the brake pad deposits on the rotor accumulate and eventually turn into a compound known as cementite. You don't want Cementite on your brake rotors. Cementite is a compound that is very hard, overly abrasive, and doesn't allow the rotors to cool properly. As a result, Cementite heats up the local area around itself growing in size and reducing the cooling capacity of your brake rotors.
Prevention: Properly breaking/bedding in your new brake rotors is vital to the longevity of the rotor. See our Brake Rotor Bedding Guide.
If this is caught early on, you can possibly remedy it by bedding in your brakes with a more abrasive pad, or resurfacing your rotors. If the heat spots are extensive, you will need to replace your rotors.

5. Rust
There are two types of rust that occur on brake rotors. Surface rust and corrosive rust. Most of the rust on brake rotors is known as "surface rust". Just like it sounds, imagine surface rust on brake rotors as a thin top layer of rust. This doesn't affect braking performance and most of it wipes off when you apply your brakes. Although some of it remains, such as on the hub and rotor vents, it doesn't hinder performance but it can be unsightly.  Our zinc and e-coated rotors aid in preventing such rotor rust from forming and tarnishing your beautiful brake rotors.
Corrosive rust on the other hand is the evil twin brother. This is the rust you see when you live in harsh conditions where road salt (electrolytes) is often used. You don't want this type of rust. This rust often happens when you neglect your car and let it sit for extended periods of time without driving, allowing the rust to etch into your rotors. This affects the structural integrity of your rotors as well as effectiveness. If this happens, we recommend replacing your rotors.
BP Coated Rotors are specifically coated with a zinc coating to protect against surface rust.

6. Warped Rotors
Although the term "warped" rotors is very commonly used, it's in fact one of the least common causes of brake vibration. In fact, what happens in almost every case of a warped rotor is simply uneven pad deposits or heat spots. Uneven pad deposits happen from using incorrect break-in procedures. Follow our break-in guide (also known as "bedding your pads") to prevent vibration and premature rotor and pad failure.

One of the most common questions we hear is: What’s the advantage of drilled and slotted brake rotors compared to stock (plain) OEM rotors? The answer comes down to improved stopping performance, better heat management, and longer-lasting braking consistency—especially under real-world driving conditions.

The Advantage of Slotted Rotors

Slotted brake rotors are designed to significantly improve braking performance. Each rotor is precision-machined with four to five slots per side (vehicle-specific), extending to the outer edge of the rotor. These slots serve several important purposes:

• Clear brake dust, water, and debris away from the pad surface, ensuring consistent pad contact
• Improve wet-weather braking by maintaining a clean friction surface
• Reduce brake fade by allowing heat to escape more efficiently
• Promote even pad wear and better pedal feel

Machined rotors deliver more responsive, confident braking, especially during repeated stops or aggressive driving.

What Do the Drilled Holes Do?

Another frequently asked question is about the purpose of drilled holes. Their primary function is heat dissipation. During prolonged or heavy braking, heat builds up between the brake pad and rotor. Drilled rotors allow this trapped heat to escape, helping to:

• Maintain consistent braking performance
• Reduce the risk of brake fade
• Extend rotor and pad life

Dimpled slotted vs. Cross-Drilled slotted Rotors

Performance rotors are available in different styles as listed in our performance brake rotors page but these two drilling styles, each designed for specific vehicle needs:

• Dimpled & slotted Rotors
  These feature shallow, non-through holes that dissipate heat without fully penetrating the rotor surface. This design maintains structural integrity, making them ideal for heavier vehicles or applications prone to rotor warping.
• Cross-Drilled & slotted Rotors
  Cross-drilled holes pass completely through the rotor, allowing air to flow through the disc for maximum cooling. This design is commonly used on light- to medium-duty vehicles and high-performance applications, where improved heat dissipation and reduced brake fade are critical.

A Worthwhile Upgrade

The noticeable improvement in braking performance, combined with enhanced cooling and cleaner operation, makes drilled and slotted brake rotors a smart upgrade over standard OEM replacement rotors. Backed by a manufacturer’s warranty and trusted by customers for over 20 years, our machined performance brake rotors deliver the stopping power, reliability, and value drivers expect.

Brake fluid is a hygroscopic fluid that starts absorbing water, making it less effective. We suggest flushing your brake fluid once a year, but it's also a good idea to bleed your fluid every 6 months if you do a lot of hard braking. Hard braking on the brake rotors accumulates a lot of heat in the brake system and "boils" the fluid, creating air bubbles. Bleeding your brake system helps get rid of those air bubbles in the system.

For both bleeding and flushing your brakes, it's recommended to have fresh brake fluid readily available. If the fluid in the reservoir runs low while bleeding/flushing, it will induce air into the system, rendering the entire process useless.

Make sure the brake fluid is fresh and hasn't been sitting on the shelf more than 2 weeks if the seal has been opened. This is important as opened brake fluid is going to contain moisture. Unlike other brake components such as brake rotors or brake pads, brake fluid is sensitive to shelf life, especially when opened.

Always wear safety glasses and use proper equipment. Use common sense and take precautions as BrakePerformance does not take responsibility for erratic driving, accidents, damages done, or personal injury.

1. On a level surface, set the car in gear and place a stop behind the tires to keep it from rolling.

2. Open the hood and locate the master cylinder. This is where the brake fluid is filled from. Open the master cylinder cap (brake fluid reservoir) and place an old rag around it as you may get some spillage. (Do not drip on the paint of the car as brake fluid will etch.)

3. Using a turkey baster, suck out all the fluid. Most likely 20% will remain and that's okay.

4. Refill the reservoir back up to the fill line using fresh brake fluid.

5. Check with your manufacturer and find out the order in which brake calipers should be bled first. Normally, it's always starting with the furthest brake caliper from the brake reservoir. For example, if your reservoir is located in the engine bay by the driver side, you would start with the rear passenger brake caliper, rear driver brake caliper, front passenger brake caliper, and then finally the driver side brake caliper. This is just a general example; make sure to verify with your manufacturer.

6. Once you figure out the order, you want to jack up that side of the car and remove the wheel to access the caliper that you are about to bleed.

7. Secure the car by using jack stands once you jack up the car and remove the wheel.

8. Locate the bleeder valve. It helps to attach a rubber hose over it so the brake fluid doesn't drip everywhere.

9. Using an assistant, have him/her pump the brakes about 4-5 times, and they should notice it get stiffer. While they are holding the brake pedal down, open up the bleeder valve and fluid will come out. The trick is that you want your assistant to notify you to close the valve right before they hit the bottom of the brake pedal.

10. Repeat this process until fresh brake fluid comes out. Usually, old fluid is darker, and you will notice the shift to a lighter fluid indicating the fresh fluid has filled that brake line.

11. Repeat the same process for the remainder of the brake calipers and make sure that the brake fluid never gets below the minimum marker on the master cylinder. If this happens, you risk getting air into the system again and having to redo the entire process.

12. Once all four corners are done, top off the fluid in the reservoir to the max line, torque the wheel bolts to the proper specification, and verify you have a solid brake pedal feel before driving.

Bleeding Brakes

The process of bleeding brakes is identical. The only difference is that when you are bleeding each individual brake caliper, you only need to open the bleeder valve once or twice until you don't see any air bubbles come out. You do not need to wait until you start seeing fresh fluid. It is still necessary to have fresh fluid as it may drain most of what's in the master cylinder.

Brake fluid is a hydraulic fluid used in your brake lines. It takes the force your foot exerts onto the brake pedal and transfers it into braking pressure that then clamps your brake rotors, effectively slowing your car down. We use brake fluid due to its hygroscopic nature and its ability to resist compression. Essentially, you transmit all your force from the pedal to the brake rotor without losing energy due to fluid compression.

Now, because the brake rotors and brake calipers exert a high amount of heat, brake fluid must have a high heat tolerance. Otherwise, it would simply vaporize inside your brake lines and negate the purpose of the brake fluid. This is dangerous and results in your brake system not functioning properly.

Boiling Point is the maximum temperature before your fluid starts to boil. To further complicate things, there is a Dry Boiling Point and a Wet Boiling Point. Wet simply means the boiling point of a fluid after it has absorbed a certain percentage of moisture* (remember, it's hygroscopic). Dry is fresh fluid from a canister that hasn't been opened.

Below, we have the quality standards for each of the fluid classes:

• DOT 3 205°C/401°F (Dry) 140°C/284°F (Wet)
• DOT 4 230°C/446°F (Dry) 155°C/311°F (Wet)
• DOT 5** 260°C/500°F (Dry) 180°C/356°F (Wet)
• DOT 5.1 270°C/518°F (Dry) 190°C/374°F (Wet)

It's always recommended to only stick with the DOT rating your car recommends.

Using a DOT rating other than what is recommended may cause improper brake operation or premature failure.

*Wet boiling point is defined as 3.7% water by volume.

**DOT 5 is a synthetic non-hygroscopic fluid and should only be used for designated cars that support DOT 5.

With all the different types of rotors available today, it can be intimidating when you don't know which one fits your needs. We get multiple calls a day from customers asking if the slotted rotors are the right brake rotors for their needs. In short, there is nothing wrong with the way plain brake rotors function, as we assure that all of our rotors are made to meet and exceed the manufacturer's specs.

Let's get back on topic. As we all know, brakes are one of the most important components to your own safety and the car's safety as well. With every driver, there is a specific driving preference which is why there is such a variety of brake rotors available.

One of the most popular and versatile brake rotors would be our slotted rotors. Slotted rotors are brake rotors with slots etched onto the friction surface of the rotor. These slots help "wipe" the brake pad clean during each pass and help maintain even pad wear as well as performance. While even pad wear promotes longer brake pad life, the slots also help direct brake dust away from the face of the wheel, keeping your car cleaner as well as preventing severe debris build-up around your brake components.

Lastly, all BrakePerformance Slotted Rotors feature slots which extend all the way to the edge. This is especially helpful during wet driving conditions as the slots help direct water on the surface of the rotor away from the friction area, reducing wet braking distance.

Often viewed as performance rotors, slotted rotors offer benefits for everyone. Regardless if it's an SUV, or daily commuter, improved braking performance in all weather conditions and better brake pad life is a plus in anyone's book.