There are 2 types of disc rotors and varies in design. Some are simply solid cast iron rotors, and others are hollowed out with fins or vanes. The weight & power of the vehicle will determine the need for ventilated discs. The ventilated disc design helps to dissipate the produced heat and is usually used on the heavily-loaded front discs vehicles.

The higher performance brakes rotors have drilled holes. This is known as cross-drilling and was originally developed in the 1960s for racing cars. The cross drilled rotors are used more & more on braking components, but is not favored for racing or other hard use as the holes are a source of stress cracks under severe conditions.

The slotted disc has shallow channels and is machined into the disc to assistance in removing dust and gas. This design is the most preferred way of most racing environments to remove gas, water, and de-glaze pads. The slotted discs are normallynot recommended on standard vehicles because they quickly wear down brake pads. However, this removal of material is beneficial to race vehicles since it keeps the pads soft and maintain braking performance.

The drilled or slotted brake discs still have a positive effect in wet conditions because the holes or slots prevent a film of water building up between the disc and the pads. The cross-drilled brake discs may eventually crack at the holes due to metal fatigue. The cross-drilled brakes that are manufactured poorly or subjected to high stresses will crack much sooner and more severely.