Media post: Myth Busting – Brake Rotors and Pads

There are myths about brake pads and rotors that need to be busted. The reason they persist is that some of them are believable. Regardless, many are still myths that have no scientific basis behind them. With the assistance of our technical consultant at Williams Brothers Chrysler of Dundee, MI, we will separate the wheat (truth) from the chaff (myth).

It takes longer to stop when your brakes are wet

When you were first learning to drive, did some adult tell you that when its rainy outside that it takes longer to stop your car? Makes sense, right? Wet brakes must be slippery and therefore take a little longer to work. Turns out that it’s not really true. Your rotor and brake pads do not absorb water so braking when wet is about the same as when they are dry.

Overheated rotors tend to warp

This one is easy to bust because according to automotive engineers, rotors don’t “warp” at all. What is often described as warping is actually the presence of two other conditions — neither of which have anything to do with warping. These conditions are brake torque variation (BTV) and disc thickness variation (DTV). Lets look at each.

BTV is a variation of rotor finish or metallurgy that causes the brake pads to slip and catch as brake pads pinch the rotor. DTV, on the other hand, is the result of the thickness of the rotor surface around the rotor. As the thickness variations of the rotor pass through the caliper, the piston moves in and out. This action generates pulsations in the brake pedal that can be felt by the driver. The solution to both of these issues is to simply replace the rotors.

Brake pads are all the same

Oh boy, this one is really a myth. While all brake pads must meet certain federal standards, there are different types of brake pads that can affect their performance and longevity. The two most common pads are your inexpensive “composite” pads and your more expensive “ceramic” pads. Both will work fine on your car, but the ceramic pads may last longer.

Brake noise is always attributable to the pads

This is not always the case but most of the time it is true. There are two types of noise that brake pads make. When they are new, some pads will squeak for a while. This is especially true with the inexpensive, composite pads. The other noise you can hear is a particularly unsettling grinding sound. This is when the brake pad material is getting low and a metal tab on the brake pad starts rubbing against the rotor. When you hear this sound, it’s usually time to perform a brake job. If you do it quickly, you might not have to replace the rotors.

All rotors are the same

Definitely not true. There are low quality rotors available from third-party part suppliers and ones that are better quality, often available from car dealers. While there is nothing wrong with the cheaper rotors, you may find that the more expensive ones direct from the manufacturer run a bit smoother and last longer.