The brakes on any car are one of the most important systems on the entire vehicle, because it doesn’t matter how much power you make if you can’t slow yourself back down before rear-ending someone or running off the track. Factory brakes are designed to provide quite, reliable braking for daily commutes or the occasional panic-stop, but for someone with high-performance driving in mind, the brakes will likely need to be upgraded.
One of the most common brake upgrades is a set of better rotors, often paired with more adequate pads as well. What are the differences between blank, slotted, and drilled rotors? Which is best? We’ve compiled a list of pros and cons to help you decide.
Good quality blanks provide plenty of stopping ability for driving in normal conditions, which is why the overwhelming majority of new vehicles come with them from the factory. They provide more surface area than an equally-sized slotted or drilled rotor, making them better at absorbing the heat energy created by braking. They are not prone to cracking under extreme use like a drilled rotor can be, and the smooth surface retains as much structural integrity as possible.
When paired with a premium brake pad and quality brake fluid, a good set of blanks is great for moderate track use.
As the name indicates, slotted rotors have grooves cut in the face where the pad makes contact. As you repeatedly step on the brakes hard (under track conditions for example), a layer of gas and brake dust begins to form between the pad and rotor, reducing the pad’s contact area with the rotor. The slots allow that dust and gas to evacuate, allowing the pad to make fuller contact with the rotor, resulting in more consistent braking in demanding conditions.
Something to keep in mind: some racing-oriented rotors come with a sharp edge on the slots that is made to cut a fresh layer of the pad as you drive, which helps with initial bite, but greatly reduces the life of the pad.
Not many things look cooler than a set of drilled rotors peeking out from behind a nice set of wheels, and they do in fact help with brake cooling. Back in the early days of racing, drilled rotors were a great way to vent the heavy layer of gas and dust produced by asbestos brake pads. Technology has come a long way since then, and modern brake pads give off much less dust and gas, making that ventilation less of an issue. Drilled rotors are more of an aesthetic upgrade than anything else these days.
Drilled rotors are more prone to stress cracking around the holes under track conditions, but they do still offer better cooling than blanks on the street.
Which is right for you?
How you will be driving your car is the biggest factor in determining which rotor style is best for you. For street-driven cars, all rotor styles will perform well, and with the exception of race-only slotted rotors, suffer no detrimental side-effects.
Something to remember though, is that changing rotor styles will not reduce your vehicle’s original stopping distance. The purpose of upgraded rotors is to better control the heat and gases associated with braking to help combat brake fade and provide reliable braking over and over.
To reduce braking distance, the best first upgrade is a set of sticky tires and track-oriented brake pads.