The Truth of Brake Rotors Explained

  Now back to looking at rotors as radiators for your brake's system, which Wilwood explains further, the overall mass or weight of an iron rotor is of prime importance when assessing its ability to manage heat cycles. A heavier rotor will cycle in a slower and narrower temperature band than a lighter rotor, and will in effect be more durable. So, just as you would select a radiator capable of cooling the engine in your Corvette, you must also select brake rotors capable of slowing your Vette down repeatedly without overheating. The overall mass or weight along with the overall surface area determines how a rotor absorbs and dissipates heat. With that in mind, examine the benefits of cross drilled brake rotors in relation to their ability to handle heat. The benefits of lowered weight are undisputable, but those benefits should not take priority over cooling capacity. Drilling a rotor, and therefore changing its overall mass, negatively impacts the way it absorbs and dissipates heat.

   As mentioned previously, the practice of cross drilling brake rotors originated primarily due to problems from the outgassing of brake pads. While it was a legitimate problem then, the issue has all but vanished since asbestos was outlawed from use in brake pads and shoes in the early '90s, and is no longer a concern. However, advocates of cross drilled rotors frequently cite pad outgassing as a concern. Pad technology has changed drastically over the years. Since asbestos was banned, newer and better methods of producing friction materials have lead to noteworthy improvements in brake performance. So, cross drilled rotors are no longer needed to combat pad outgassing, but they still help dissipate heat quicker, right, on the contrary. When you consider absorbing and dissipating heat is a brake rotor's primary function, lowering its overall mass by cross drilling the rotor will reduce it's cooling capacity as well as its durability. Cross drilling isn't the cooling solution that many have been led to believe. If you're already experiencing heat related brake issues, changing to a rotor that started at the same weight as the original, and was lightened by drilling holes in it, will not improve the thermal stability of your braking system. You need a heavier rotor, not a lighter rotor. Many Corvette owners also believe that cross drilled and slotted rotors improve performance by increasing the level of friction between the rotor and the pads, that is simply not true. Tests have shown that the surface pattern on the rotor, whether it's solid, cross drilled, or slotted, does not change a rotor's friction characteristics, and has no impact on brake torque.