Brakes are important and you we all know that, we also know how they work. Brake rotors are one of the most critical components of the braking system that the system employs. There are design difference that you would find among the ones that come as standard and the ones that are available in the market and are sold as “performance rotors”. What’s the difference and how do these changes make a difference, we take look.
It’s important to understand that brake rotors require cooling and if they don’t lose heat quickly, it can cause brake fade. Most design features are added keeping that in mind.
Almost every other car that’s there on the road uses ventilated rotors. Solid rotors, if present are generally secondary and are present on the rear wheels. Ventilated rotors are most efficient when it comes to cooling and are easiest to manufacture. The radial slot grooves let the air in and as a result cool the rotors due to temperature difference.
When a brake pad comes in contact a brake rotor, due to friction heat is generated. In certain cases, compounds transform into gases, which creates a barrier between rotor and brake pads. This prevents any further contact which results in loss of braking efficiency. Drilled holes are essentially added so that gases can escape and there’s no loss in braking efficiency. Drilled holes are always present in conjunction with the vents.
Drilled holes are created through machining operations and generally have micro cracks surrounding them, in combination with the thermal stresses, make these mechanically inferior to the ventilated rotors.
Advancements in material chemistry make drilled holes redundant. However car manufacturers continue to use them largely for aesthetic purposes.
Slots are also added for the reasons for which the holes are drilled i.e. They somewhat also increase the bite capacity of the brakes due the larger surface area that comes in contact, but the effect is somewhat minimum. It also helps wipe the brake pad clean. An adverse effect of the slots can be an increased pad wear.
Slotted rotors in combination with the vents are generally regarded as the best combination.