What kinds of brake discs are there?

Brake rotors come in many different types. Before you can purchase a fresh set of brake rotors, you must understand each of these different types, what sets them apart, and what are the pros and cons of every style. The four kinds of brake rotors are:

Drilled Only – Drilled brake rotors are easy to recognize because they have a series of holes drilled into the metal.

Slotted Only – Slotted rotors have slots, which look like lines in the metal.

Drilled & Slotted – Drilled and slotted brake rotors combine the drill marking and slot marking.

Blank or Smooth – As the name suggests, blank or smooth brake rotors have a smooth or plain surface, with no holes or markings in the metal.

Drill holes and slots in rotors can both improve braking, but under different braking scenarios. To understand how these rotor modifications can improve stopping power, it is first necessary to understand the three forms of heat transfer:

Conduction: When there exists a temperature gradient within a body, heat energy will flow from the region of high temperature to the region of low temperature. This is conduction. Conduction heat flows from the edge of the rotor through the hub bearing, and it also flows through the brake pad into the caliper.

Convection: Air flow dissipates heat from a body. Normally, the higher the air flow over the rotor, the more heat is removed. The rotor vanes act like a fan blade to move air from the inside of the rotor to the outside edge. The rotor vanes helps remove heat through convection.

Radiation: heat is removed through infrared radiation (electromagnetic radiation that is not visible). After you drive your car, stop and pop the hood, you can feel the heat with your hands above the engine without touching it. You are feeling the infrared radiation coming off the engine.

All three methods of heat transfer occur when you apply the brakes. During a typical stop, the heat transfer is about 25% conductive, 35% convective, 40% radiation. For a high temperature, high speed stop, the heat transfer is about 15% conductive, 40% convective, 45% radiation. At high speed, convection heat transfer is very important. This is why drill holes can help reduce the brake temperaure. The drill holes help air flow through the vanes. The brake temperature can drop up to 180 degrees. Brake pads work better at lower temperatures, and you reduce the risk of pulsating brakes as well.

After you have reviewed the styles of brake rotors and can tell each of them apart, you must learn about the advantages and disadvantages of each style for the type of car you have. Since every car is different, what is fine for your light truck may not work very well for your sports car and vice versa.