The slender new look for disc brake rotors.
Over the last decade or so disc brake rotors have taken on a new slimmer look and many wonder why. If you are an old-timer you will remember an enormous, big fat brake rotor. When you replaced your brakes you would always machine several thousandths of an inch off of each side of the rotor each time the brakes were replaced and the rotor seemed to last forever.
So why spoil a good thing? There are a couple of reasons that over the years manufactures decreased the size of disc brake rotors. First as you probably know that the cost of steel and other metals have increased dramatically over the years. And when a manufacturer can save a few dollars on each car and multiply that by millions, they will if they can always decide to take the cheaper route.
The government further has imposed MPG (Miles per gallon) guidelines and standards. So where the car manufacturer can make a vehicle lighter that helps with fuel efficiency. With the combined benefits of a lighter vehicle and the less expensive product the decision is made to make brake rotors as thin as possible.
But beauty is in the eye of the beholder. What is good for the car manufacturer is not such a good thing for the consumer. These new thinner disc brake rotors have a tendency to distort which causes brake vibration and pulsation. Many times the rotors can be machined but if you choose to do so it is very likely that the same brake vibration / pulsation problem will return in short time. This leads to an increased maintenance cost to the consumer.
- What do we recommend? If you don’t have a vibration or brake pulsation problem when you are replacing your brake pads, do not machine the rotors as part of the repair. It is difficult for old-timers to understand this because to them changing brakes means also machining rotors, which was true then, but no longer. Many manufacturers now agree making statements that rotors should not be machined unless there are groves beyond .060.
- What happens if you machine a rotor as part of normal brake service? Some manufacturers deem there rotors non serviceable. Others will allow small tolerances for machining. If you choose to resurface a rotor that there no problem with you may be creating a problem. The theory being, the thicker rotor is venerable to vibration / pulsation the now thinner rotor is now more venerable. That is why many customers entering a shop for a simple brake repair soon returns with a brake vibration or brake pulsation complaint.
- Should I have my brake rotors machined if I have a brake vibration or brake pulsation? Always ask for a price of machining the brake rotor VS replacing. Machining the rotor will cost approximately one hour labor or about $100.00 each and may only be a temporary repair. In many cases you can replace the brake rotor with a new one for the same cost. The repair shop obviously makes more by machining your rotor because they make their money by selling brake labor, we don’t believe that is the best route for the customer. Choose wisely!