For BMWs manufactured after 1992, when your vehicle needs brake repairs, it includes not just brake pads, but requires that the brake rotors be replaced as well. As expected, the cost for a BMW Brake Repair is more expensive than on a vehicle that allows for machining of the rotors. The reason is because the high performance requirements of the BMW automobile has led designers to reduce the overall weight of every vehicle. As such, the rotors are thinner and there is no excess material to machine the surface.
Warning! Warning! Warning!
This is the warning that is activated when either of the two brake pad sensors is worn below minimum thickness. The brake pads wears through the normal friction against the rotors during braking. Once the pad wears below a pre-determined thickness, the sensor is triggered when the rotor cutting in, completing the lighting circuit to the dashboard’s warning light.
Please be advised: there is no rotor sensor! The rotors on your BMW’S brakes must retain a minimum thickness as specified by the manufacturer.
The minimum thickness of the BMW brake rotors is necessary to dissipate the heat produced from the friction of braking. Additionally, the rotor, as designed, must retain the minimum thickness to maintain the performance of your BMW’s brakes. Should the rotors wear down to less than the specified minimum thickness, they will warp from the heat developed during braking. For this reason, every time your brake pads are replaced, your Everett BMW Repair Specialist at Conaway Motors will measure the thickness of the rotors.
Your BMW technician will measure the thickness of the brake rotors to assure they are at least 20.4 millimeters (mm) thick. As you can see, this rotor is below the specified thickness, at 20.11 mm. As such, this BMW owner will definitely have a complete brake job! Because the BMW rotors are machined so close to required thickness, it is estimated that nearly 95% of all BMW Brake Repairs require brake rotor replacement as well. It is impossible to “turn the rotors” with such tight tolerances. It is strongly advised that if, when having the brake pads replaced, that if the rotor thickness is close to the minimum thickness, definitely replace the brake rotors at this time. The potential catastrophic brake failure should you not replace nearly worn brake rotors will cost you much more than have the work performed.
But Why Would BMW Make the Rotors so Thin?
Since one of BMWs primary design parameters is for ultimate vehicle performance, every bit of weight reduction is sought after. This is especially pertinent for weight by the wheels of the vehicle. The metals used in brake rotors is very heavy, so reducing the thickness (x4 brake rotors) is a substantial weight savings.