The amount of heat dissipated by the rotor depends on the surface area and mass of the rotor, or the diameter and thickness of the rotor. This heat dissipation is often improved by venting, which helps force the heat away from the rotor. Some rotors may have a specific vent direction and may only be fit on a certain side of the vehicle.
Brake rotors are usually made of solid cast iron, which has excellent heat absorption properties. Composite rotors are made of a stamped steel inner hat surface along with a cast iron friction surface. Composite rotors are designed to save weight and lower production cost. An improvement of this design is the floating rotor, which features a billet aluminium hat portion and a high carbon cast iron friction surface. The floating rotor reduces thermal stress and the unsprung mass of the vehicle, which allows for improved handling and braking performance.
BUT THOSE SLOTS AND HOLES KIND OF LOOK BETTER ON A VEHICLE. SHOULD YOU GET THEM FOR THE LOOK?
Sure. If that is what is important to you. But you should note that performance-wise, when replacing brake discs, it is always a good idea to replace them with the type of disc you originally had installed. BLANK / SMOOTH discs are perfect for standard cars/driving, but if you care for performance levels or looks you can compare the three types in our infographic.
ALL SURFACE TYPES WILL PERFORM SIMILARLY WITH STANDARD DRIVING
SMOOTH / BLANK OR PLAIN BRAKE DISCS are the best for standard driving and will perform the same as the other two types, with very few noticeable differences.
Smooth / Blank rotors have the most surface area and are highly effective as a heat-sink. They are least prone to cracking. Smooth rotors are recommended for most vehicles that are not used for extreme or repetitive braking.
BRAKE PAD GRIP IS STRONGER
SLOTTED and DRILLED rotors have a slight advantage over smooth rotors when it comes to the grip of the pads when you apply the brakes and you will notice this in the initial phase of braking when you press the brake pedal.
BETTER HEAT DISSIPATION
SLOTTED and DRILLED rotors have better fading resistance due to better dissipation of heat and gases. This is why these kinds of rotors are mostly seen and used on the race track vehicles. But if you are not heading to the races every day, a plain vented rotor will be as good as the other two types.
LESS FRICTION WITH PLAIN ROTORS SAVES THE PADS
BLANK / SMOOTH rotors will not wear the brake pads so quickly due to less friction on the brake pad surface. Similarly, the inevitable rotor wear will be more even than with the other two options.
MORE DIMPLES, HOLES AND SLOTS - MORE CRACKS
The biggest advantage of BLANK / SMOOTH discs is they are not prone to cracks as much as the other two options because the braking surface is smooth and solid. DRILLED rotor will most likely crack under extreme use.
COOLING IS FASTER WITH DRILLED ROTORS
DRILLED discs dissipate gases and heat directly to the interior cooling vanes of the rotor lowering the temperature of the brakes faster than the other two options.
DRIVING IN WET CONDITIONS
DRILLED and SLOTTED discs allow water to be quickly removed from the rotor surface, so in wet conditions, these two options have an advantage over the rotor with a smooth surface.
Now you have it. Some guidance on what to look for and what to take in conideration when choosing your new brake discs. And you can save time on labor and buy a complete brake kit, including brake pads, rotors and sensors from newparts.com