What’s the purpose of drilled rotors or slotted rotors?
Crossed drilled rotors and slotted rotors (and rotors that are both slotted and drilled) are designed to allow gases to escape that build up between the brake pad and brake rotor. This allows your brakes to run cooler and stop better.
Cross Drilled Rotors
Cross drilled rotors are OEM style blank rotors that have been cross drilled to allow heat to escape that builds up between the brake pad and rotor through the drilled holes. Many people prefer drilled rotors because they like the look and consider it a good upgrade over an OEM blank rotor. Over the years, we have seen drilled rotors crack between the drilled holes due to the rotor being low quality and extreme brake temps causing excessive heat. This shows us that even though drilled rotors are specifically designed to expel hot gases, cheap or inexpensive rotors aren’t drilled in the proper way or with proper drill locations, so the purpose is for looks and not for performance. If you are buying a drilled rotor, a quality brand such as EBC, Brembo, or Wilwood would be best. (Ebay non name brands just stay away). The image below shows what can happen with a low quality cross drilled rotor when it cracks.
Slotted brake rotors are a great alternative to drilled rotors because they serve the same purpose of expelling hot brake gas, but since they retain the strength of the rotor, they do not crack like drilled rotors can. We highly recommend slotted rotors such as StopTech. Some people argue that the drilled rotors are more for show, and the slotted rotors are more for race and performance. Slotted rotors are also better designed for wet conditions as they move water away from the rotor more efficiently for superior wet braking.
Less Brake Fade and Longer Life?
Brake companies say their rotors have double the life over stock rotors and have less brake fade, but we haven’t seen this. Usually the less brake fade comes from people upgrading their brake pads at the same time but since most brake pads offer better stopping power, they dig deeper into the rotor so any benefit the rotor has from higher quality material is offset by the more aggressive brake pad that eats away at the rotor material.
What’s best for the street vs the track?
Most will not notice a difference in stopping performance from the brake rotor, but rather from the brake pads. The advantages from cross drilled and slotted rotors comes during extremely hard and repetitive braking such as in competition use. For the best bang for the buck, we recommend a good set of brake pads and if your car is older with rubber brake lines, to replace them with stainless steel brake lines.
For the track or the street, a good quality slotted brake rotor and high quality brake pads. If you decide you want the look of a drilled rotor, go with a high quality brand to lower the chance of cracking between the drills.