Brake Rotors

A disc brake assembly includes the brake rotor, friction pads, and brake calipers. The brake rotor provides the friction surface for the brake pads. The rotor is mounted to an axle or hub and turns with the wheel, and the pads are mounted in the caliper that straddles the rotor. When the brakes are applied, hydraulic pressure forces the caliper piston(s) outward, in turn clamping the brake pads on both sides of the rotor, slowing and stopping the vehicle.

When compared to drum brakes, disc brakes naturally run cooler because their friction surface is exposed to the air, unlike the enclosed friction surface on drum brakes. Cooling is further improved on vented rotors that have cooling fins cast in between the friction surfaces. Solid rotors are used on small, non-performance cars, and some vehicles have vented rotors in front and solid rotors in rear. Most rotors are separate components sandwiched between the hub or axle and the wheel, but some are cast integral with the hub. Most rotors are made of cast iron, but some are composite, with a cast iron friction surface and steel center section.

Rotors can suffer from several defects that disqualifies them from further use. Visually inspect the friction surface for scoring and grooving caused by wear, dirt, or brake pad backing plate contact. Measure the rotor thickness. All rotors have minimum thickness, or discard, specifications that are usually cast or stamped into the rotor center section. A rotor that is too thin will not have the ability to dissipate heat, and could warp, crack or otherwise fail if used. Another rotor problem is excessive runout and thickness variation that can cause annoying pedal pulsation. Runout can be checked with a dial indicator.

It used to be common practice to machine rotors, but today’s rotors are very thin to save weight, and cutting them will only make them more prone to warpage, and scoring and grooving can be too deep to be removed without exceeding minimum thickness specifications. And some defects like heat checks and hard spots can’t be machined away. For an effective, long lasting repair, your best course of action is to install new brake rotors, and always in pairs per axle. We have a large selection of replacement rotors made to OE specifications for metallurgy and surface finish, for smooth, quiet braking performance.

If you push your car hard on twisty roads or at the race track, or your hard-working truck gets rigorous use, you can experience brake fade and dangerously longer stopping distances with factory brake rotors. You can get the performance you want and the safety you need by upgrading to performance brake rotors. They have metallurgy and features specifically designed to dissipate heat and remain true, for superior braking performance even under severe operating conditions. We offer a large selection of rotors in a variety of constructions so you can get the rotors that best suit your needs and budget.