The term 'rotors' is more commonly used in the USA than in the UK but the products are the same; the term rotors actually refers to the brake discs on a vehicle. These parts are what are responsible for the slowing down and eventual stop of the vehicle in question, and work in conjunction with brake pads to ensure the braking process works correctly each time. The brake pads will press onto either side of the disc to cause friction, which will then cause the wheel to stop.

It is important that these parts are kept in good condition throughout the lifetime of the vehicle; it may be they will need replacing at regular intervals to ensure the braking is not impaired in any way. Rotors that are damaged will obviously not work to their best performance, and this may cause the vehicle they are fitted on to be unable to stop in a situation on the road, leading to a crash or accident. The most common causes of damage to brake discs are rusting (to excess), scarring, cracking and/or warping. These problems are often seen by mechanics looking for any problems with the discs and they are either replaced or repaired using a method called skimming (or rotor turning, in the US). This is where a very thin layer is skimmed off the face of the disc, leaving a uniform thickness and repaired surface behind.

The four common problems with brake discs are caused by a variety of factors. Rusting, for example, is normal as most brake discs are made from cast iron, which rusts comparatively easily. This rust is usually worn off as the brakes on the vehicle are used, but if they are left standing over long periods of time, the rust will become too severe for this. Scarring (or 'scoring' in the US) of the brake discs happens when the brake pads that press onto the discs have gone beyond their service life and are actually scarring the disc as they touch it. Brake pads have a metal backing plate that sits behind the friction material, but when this is all worn away, this plate presses directly onto the rotors. This will produce a loud squealing noise more often that not, and cause deep scars in the surface of the brake disc. Cracking is mainly seen on drilled discs – where the holes are drilled into the discs, cracks will appear around the edges. Finally, warping is caused when the rotors are exposed to excessive heat – this can be due to hard braking, people riding the brakes and/or a stuck brake pad (where the pad is pressing on the disc all the time).

Different garages will charge different prices for repair or replacement work on brake rotors, and the discs type required will also vary depending on the vehicle they are fitted on to. Therefore, it is important to choose a garage that have a longstanding reputation in their field for being knowledgeable about the subject matter, to ensure you get the best quality work possible for your money.