Which to Buy: Cross Drilled vs. Slotted Rotors

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Cross Drilled vs. Slotted Rotors

There’s no denying brakes are the most critical component of the entire vehicle. Having a powerful engine with a lot of horsepower will turn some heads, but if your brakes aren’t strong enough to control that speed, then you would be putting yourself in danger and risk getting in an accident. Just like in life, it’s what’s on the inside that matters!

With major improvements in technology, modern day factory brakes are able to withstand the wear and tear of a daily commute and stop your car on a dime when a pedestrian suddenly bolts out into the middle of the street. A huge reason why this is possible is because of the braking unit that is responsible for controlling this stop, i therotors.

For those who may be looking to upgrade their braking system, investing in cross drilled or slotted rotors may be your best answer. In this article, we are going to outline the qualities of slotted and crossed drilled rotors so you can make an informed decision on which one is right for you when it’s time to replace.

How the Braking System Works

Before we get into the different types of rotors, let’s first talk about the braking system as a whole and what purpose rotors serve in your vehicle.

A modern hydraulic disc braking system is made up of several complex parts. The three most important components include:

  • The Disc rotor
  • The Brake Caliper
  • The Brake pads

The disc rotor is attached to the wheel hub, freely spinning with the wheels as the vehicle is in motion. The brake caliper is fixed in place and contains the brake pads. These pads are activated by pistons that fire via a pressured hydraulic system, which causes them to squeeze against the surface of the disc rotor and create friction. This, in turn, allows the brake rotors to slow down and bring the wheel to a complete stop.

Think of the disc rotor as a spinning ceiling fan, and the brake pads are a stick reaching between the fan blades to stop it from spinning.  The fan won’t come to a complete stop immediately, but if the stick is strong enough it can make the fan stop spinning pretty quickly when its placed between the fan blades.

That’s how a braking system works!

Now that you’ve gotten a general idea of how the braking system works, let’s take a look at some of the main duties of the rotors.

The idea itself is fairly simple. When a car is traveling at fast speeds, it naturally creates kinetic energy. This energy is caused by friction from all the moving pieces within the braking system. Once the kinetic energy turns into heat energy, your car can use the heat to help it stop moving.

This is where brake rotors come into play. The heat energy that was created by friction is absorbed by the brake rotors, allowing the car to safely stop time and time again without overheating.

If the disc brakes were unable to handle all this heat, it would be very difficult to bring your car to a complete halt.

What are the Different Types of Disc Rotors?

Just like with all things in life, not all rotors are created equal. That means there are other disc varieties that offer better functionality and performance compared to the standard smooth rotor styles that most cars are built with.

For example, disc brake rotors with a larger surface area can dissipate heat more effectively than smaller varieties. Furthermore, when drilled holes or grooved slots are also added to the disc rotor, they can provide further ventilation to remove heat, debris, and gases that are often generated from the brake pads.

Upgrading your rotors means adding more ventilation methods to your braking system, which in turn helps the discs last longer and stop your car quicker. Below are the most common types of rotors available on the market today.

The Traditional Smooth Rotor

The smooth rotor is the most typical style. Why? Because it does its job and it does it well. Because Smooth rotors are made without holes or slots of any kind, they maintain maximum structural integrity, meaning they are less likely to crack or break under pressure.

The Impressive-Looking Cross Drilled Rotor

Cross-drilled brake rotors are those that have holes drilled through the entire rotor. Once considered superior to smooth rotors for everyday driving, now they are mainly used solely for their cool aesthetic appearance.

The High-Performance Slotted Rotor

Slotted brake rotors have machined grooves or ‘slots’ on the surface of the disc rotor. Unlike cross drilled rotors, these grooves do not pass all the way through, which help to reduce temperatures for better performance.

The Versatile Drilled & Slotted Rotors

As the name suggests, these drilled and slotted disc rotors have both drilled holes and machined slots. While these added holes do help with superior airflow and ventilation, they, unfortunately, have less surface area compared to other varieties which can compromise the effectiveness of the brake itself.

Now that you understand the 3 major types of rotors, let ’s discuss the similarities and differences between cross-drilled rotors and slotted rotors.

Cross Drilled vs. Slotted Rotors: Are They Really That Different?

The short answer to this question is yes, these two types of rotors are in fact different from one another and serve their own purposes. This next section will give an in-depth description of both cross drilled and slotted rotors so you can have a better idea of which option is best for you.

Cross Drilled Rotors

As discussed earlier, cross drilled rotors allow air to ventilate through a series of holes, which also allows steam, water, and debris to escape as well—making them the ideal rotor for wet weather conditions.

Today’s brake pads have been built to be much more efficient at handling higher temperatures than they were before, making the build-up of gas far less of a concern as it was previously.  So, while cross drilled rotors are still beneficial in some ways, they are not as necessary as they once were when brake pads produced more gas.

However, they still have one strong selling point that keeps customers buying. For many, they are considered to be the most aesthetically-pleasing option and offer a cool look to the braking system as a whole.

Their preferred appearance does come at a price, though. One of their main downsides is that cross drilled rotors are not as effective at dispersing higher temperatures that come from heavy-duty braking. Over sustained periods of heavy use, the spaces between the holes turn into a stress point, making them vulnerable to cracking and breaking.

More holes also mean a smaller surface area to disperse heat. However, the increased ventilation allows the brake pads to stay cooler and last longer when it comes to daily driving at more ‘moderate’ brake temperatures.

For this reason, it is not uncommon to see modern high-end luxury vehicles and performance cars equipped with cross drilled rotors direct from the factory. Drilled rotors are certainly not as advantageous as they once were, but they are still a great option for everyday use, and they look good as well.

Slotted Rotors

Slotted rotors enjoy almost all of the same benefits as drilled rotors, but with the added advantage of having a greater surface area to dissipate heat.

The larger surface area allows the brake pads to have more contact with the rotor, resulting in more friction. A higher friction coefficient allows the pads to ‘bite down’ more consistently with the same amount of power that would be used on a cross drilled rotor but with greater results.

This added efficiency also works to combat brake fade and makes them ideal for larger vehicles and towing.

Slotted rotors differ in that they employ several grooves along the face of the rotor, which assists airflow and provides a catchment area for water, steam, and debris to run off into—without compromising the structural integrity of the rotor.

A downside of the increased surface area is that it can lead to more wear and tear on brake pads as a result of consistent heavy-duty braking.

Which To Buy?

So now that you’ve gotten an in-depth look at both these options, do you know which rotor is best for you?

If you need a braking system that creates serious stopping power for your performance vehicle, slotted rotors might be the right choice for you.  This rotor is also recommended for those with larger vehicles or those looking to tow a heavy load.

But if you’re not looking for added braking performance or rotors that are built for excess use, your daily driving needs can be met perfectly with cross-drilled rotors.

Plus, they’ll perform better in wet weather conditions and will have the benefit of looking awesome.

Before making a purchase, make sure to also consider floating vs solid rotor options as well.

When it comes to brake disc rotors and braking systems, do your research and remember that quality is key. Consider first the needs of your vehicle, and also your desired budget.

Whether it’s daily driving, towing cargo, grand touring up the coast, or tearing up the racetrack, don’t forget that at the end of the day—good brakes can save your life.

1 COMMENT

  1. I have used smoth rotors more then any others. I had a rotor crack on me over 700 miles from home. I bought another rotor and put it on in the rain.

    I have also used drilled and slotted rotors and was pleased with them and there better stopping power. I am now looking once again to drilled and slotted for my 1500 Ram. I have noticed its braking power has started to slip. My problem is I ts a full sized truck.

    I wish there was some way to know i am getting high quality brake parts as the only time i had a problem I blam it on poor quality rotors.

    So once more i will be getting drilled and slotted rotors for my first time brake job on this truck.

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