Often the vibration sometimes experienced when braking is referred to as being caused by bent or warped rotors, but this is in fact an incorrect term. EBC Brakes has never seen a warped brake disc or rotor due to use. Brake rotors are made from cast iron, a very tough and durable material, and there is a reason for that – they can be run to red heat and cooled time after time without distorting. Brake rotors simply do not warp. This is why cast iron is used for brake rotors the world over – there has never been another material that can beat it and very likely never will be. What EBC has commonly seen happen is brake vibration after 3000-6000 miles that is actually caused by run out (unevenness of the brake rotor surface), at install, which can be caused by unintentional misalignment of the brake rotors or an anomaly on a particular vehicle (one in seven vehicles have steering geometry issues that can cause brake vibration, even from new, or after bumping a curb or running over a pothole).
The only true cure for vibration due to an uneven brake disc surface is by turning the rotor with a brake lathe (actually removing a thin layer of the brake rotor material to return it to a smooth and even surface). For many premium car companies (such as Jaguar, Porsche, BMW, Honda, Landrover, etc.), steering geometry is such an important issue that they will even turn new brake rotors after install as part of their fitting procedure. What turning your vehicle’s brake rotors with a brake lathe will do is properly align your discs or rotors to your vehicle, deliver smooth and consistent braking and prevent DTV (Disc Thickness Variation), for many thousands of miles. Turning your brake rotors every time you change your brake pads is a good practice to prevent future problems with brake vibration.