How do Slotted Rotors Actually Improve Braking Performance?

If you’re a fan of sports cars, or maybe even own one yourself, chances are you recognize that upgraded rotors are important — even if you may not realize why. Having slotted rotors is also an upgrade that you can do to many cars, but if you don’t understand what about these altered rotors gives them performance capability, there is a chance that you’re wasting your money. When it comes to drilled or slotted rotors, there are a lot of misconceptions, but how do slotted rotors actually improve braking performance?

The myth behind slotted rotors

Chances are you have heard that the reason slotted rotors perform better than standard flat rotors is because the slots allow for better heat dissipation. While heat is a factor that comes into play, especially because braking systems rely so heavily on friction, a physical process that creates heat, it might not come into play in the way you may think. Drilled and slotted rotors themselves are different, not just in name but in the way that they improve performance of the braking system of some vehicles, but they aren’t necessarily the same.

A visual comparison between drilled rotors and slotted rotors | Brembo
A visual comparison between drilled rotors and slotted rotors | Brembo

Who needs slotted rotors?

According to Brembo, one of the most widely recognized manufacturers of performance braking systems in the automotive industry, slotted rotors are recommended for cars that put extreme uses, but they admit it can be a pointless expense in some circumstances. Their website also points out that different types of brakes are required for track cars. Of course, they do just look pretty darn cool sitting inside your wheel, especially if your car requires excessively large rotors like the Lamborghini Urus does.

A detail of the tire on the #88 National Guard Chevrolet, of Dale Earnhardt Jr. during practice for the NASCAR Sprint Cup Series FedEx 400 | Patrick Smith, Getty Images

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What do slotted rotors do?

Slotted rotors do actually help improve braking performance under certain circumstances. In more complicated terms, the slots in the brakes increase the rotor’s friction coefficient, meaning that it allows the brake pads to grip the rotor more effectively. The slots also interrupt a thin sheet of water than can form in case of rain or standing water.

More than that, the presence of the slots allows the braking system to dissipate gasses that build up on the rotor’s surface as the brake pad and rotor press together. These gases, when combined with the heat produced by the friction, cause what people refer to as ‘brake fading’ which can make it feel like your brakes aren’t working as effectively over a driving period.

A display of the various rotors offered by Brembo
Brake discs of the brake manufacturer Brembo are exhibited at the IAA | Silas Stein/picture alliance, Getty Images

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While slotted rotors can greatly increase your car’s ability to come to a stop as quickly and effectively as possible, it isn’t necessary for all cars. In fact, for a standard passenger car or sedan, the flat rotors that your car comes with from the factory are usually exactly what your car needs, and they are typically less expensive to replace. To ensure your car provides the best braking experience possible, regular maintenance of your braking system should be completed.