Solid and vented rotors made with gray cast iron are the most common types of rotors. Drilled and slotted rotors are a variation of the same design. A solid brake rotor is just that – solid. There is no space between the two friction surfaces. A vented brake rotor more commonly has a space between the two friction surfaces of the rotor. This helps with cooling and is more common on the front of the vehicle because front brakes do 70-80% of the braking and endure the most heat.

Unlike slotted or drilled faced rotors, general stock replacement rotors are normally solid faced rotors that are either solid or vented. When replacing a rotor, there should be little confusion as to whether you need a vented rotor or not. If your car came with a vented brake rotor, then the replacement part will be a vented brake rotor. If the car came with a solid brake rotor, the replacement part is a solid brake rotor. No solid rotor replacements are available for a vehicle that came originally equipped with a vented rotor.

Slotted and drilled rotors are a performance modification that do not increase braking power, but might aid in the cooling of the rotors in high heat situations. There are both advantages and disadvantages to having slotted or drilled rotors. One rule of thumb is that if you are just daily driving, there is no reason to get slotted or drilled rotors other than to improve the way your rotors and wheels look. (Drilled and slotted rotors can have an aesthetic appeal to them because they may have a rust prevention measure applied to them and can be indicative of a performance braking system.) One disadvantage of drilled rotors is that they will provide more friction against your pads and reduce the life of them. Another disadvantage is the potential for a drilled brake rotor to crack when subjected to thermal stress. A drilled hole can upset the grain structure of the metal; the result is an uneven temper in the metal. As the brake rotor cools, the uneven temper can cause cracks. The most common crack seen is located from the outer most drilled hole to the edge of the brake rotor. Since the edge of the brake rotor is the first to cool, this is where the most uneven area of cooling occurs. For this reason, drilled rotors are not well suited to racing conditions in which high brake component temperatures are always occurring. Cracks cause vibrations and the larger the crack the more dangerous. The advantages are that the scrub friction of the holes and slots, while increasing the wear on your pad, reduce the chance of the pads becoming glazed.