Brake rotors are metal friction discs that rotate with your road wheel; the rotors are clamped by a caliper and brake pads, which, when activated by the brake pedal, squeeze the pads against the rotor slowing and stopping the rotor.
Brake rotors are metal friction discs that rotate with your road wheel; the rotors are clamped by a caliper and brake pads, which, when activated by the brake pedal, squeeze the pads against the rotor slowing and stopping the rotor.
Where are Brake Rotors Located?
Brake rotors are located behind the road wheel. While all passenger cars will have rotors fitted to the front, some basic models may not have rotors fitted to the rear.
As most passenger vehicles employ wide-open spoked road wheels, rotors are clearly visible without removing the road wheel.
Rotors are visible behind the wheel.
Common Brake Rotor Problems
There are two basic flavors of brake rotors – Solid and vented.
The solid rotor often fitted to small inexpensive cars both front and rear and is commonly fitted to the (rear only) of family-size cars.
Vented rotors as the name suggests allows for greater airflow around the rotor aiding in performance. This is the most common type of rotor fitted today.
There are of course high-performance rotor options too. Drilled rotors offer cooling and greater moisture dissipation and instead of metal, there are ceramic and also carbon fiber rotor options, but you won’t find these on too many passenger vehicles.
Brake rotors are basic technology are don’t suffer from a ton of issues; the enemy of rotors is excessive heat.
The most common brake rotor issues include:
Brake Rotor Worn
The business of slowing your vehicle may be described by a scientist as turning kinetic energy into heat. Or a mechanic might say braking causes a ton of heat, all that brake pad on rotors friction causes it to heat up but also to wear a little.
So although rotors are harder than brake pads, they still wear out.
Hard to say how long rotors last as a lot depends on driving style, loads carried, terrain, and environment. City driving causes more braking and, therefore, more wear.
A set of rotors may last the typical driver somewhere between 40,000 and 60,000 miles. And bear in mind the wear tolerances on a set of rotors may be no thinker than a few thousand of an inch.
In fact, if your thumbnail catches on the lip at the top of the rotor, chances are you need your rotors changed. A more scientific way to check them is to use a micrometer to check the thickness at several points. The minimum spec is engraved into the hat and around the side of the rotor.
Brake Rotor Warped
Warping is another common issue with brake rotors. Warping causes the disc to get out of shape, and that causes the foot brake to pulsate when the brakes heat up a little.
Not to be confused with ABS activation, a warped rotor pulse is easy to identify as the pulsing is relative to the speed of the vehicle.
Warping is usually caused by wear; as the rotor’s disc becomes thinner, they are unable to handle the constant heat cycles.
Warping may also be caused by excessive heat, and that may be caused by an over-enthusiastic driver, hauling heavy loads downhill, or a dragging brake issue.
It should be noted cheaper brake rotors tend to warp easily; I advise spending a few dollars more and fitting good quality rotors, just one overheating event can warp cheap rotors.
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John Cunningham is an Automotive Technician and writer on Rustyautos.com. He’s been a mechanic for over twenty-five years and has worked for GM, Volvo, Volkswagen, Land Rover, and Jaguar dealerships.
John uses his know-how and experience to write articles that help fellow gearheads with all aspects of vehicle ownership, including maintenance, repair, and troubleshooting.