Taking Care of Your Brake Rotors – Everything You Can Do on Your Own

A brake rotor is a metallic component attached on the wheel hub. This is a part of the braking system that can be seen through the spokes. The rotor is what the brake pad pushes onto when you apply the brake pedal. The purpose of brake rotors is not only to act as a braking surface but also to absorb and dissipate the heat generated from the friction between them and the brake pad.

Are Brake Rotors and Discs the Same Thing?

Brake rotors are basically discs made from iron and steel. Rotors are also known as a disc brake rotor as they are in the shape of a disc. So, that makes them one same thing.

Common Issues

Warping

When the rotor is warped, it means that its surface is deformed. This happens due to pad material building up on it. Over time, this layer can become thicker and make the rotor’s surface uneven. Warping can also occur due to the varying density of the disc brake rotor – areas that are not as dense can wear down faster and therefore the surface becomes uneven. This isn’t the case with high quality rotors.

Corrosion

Steel is a corrosion prone material and the one used for rotors is no different, especially if you live near the coast. Rust doesn’t make for a serious problem as it usually gets scrubbed away by the operation of the brake pads when using the vehicle regularly. This doesn’t let the rust build up to the point where it becomes an issue. But if your vehicle sits outdoors for long periods of time, then corrosion can occur and become problematic.

Galling

Another issue low quality rotors experience is galling which occurs due to the insufficient hardness of the rotor. This makes the pad gauge the surface of the rotor which can happen quite easily especially when there is a lot of heat that can soften the surface. Galling makes brake performance less efficient and the braking bumpy.

Run out

When the rotor is slightly off axis, the brake pad doesn’t get fully in contact with it which is why this is called rotor run out. These are very small deviations which can significantly affect braking and can be caused by dirt or rust between the rotor and wheel hub. This may be mistaken for warping, but in this case the rotor still has the same thickness throughout its surface, the issue has only to do with the inboard and outboard surfaces not being parallel.

What You Can Do

Rotor Thickness

Rotor thickness should be checked about every 16000 km or even more often to ensure the brakes don’t start to squeal and cause damage. Rotor thickness should be measured using a micrometer inside the outer circumference at every 45°. When measuring rotor thickness make sure you do so about 1 cm from the rotor edge as the pad doesn’t get into contact with it. If the rotor is slotted or is dimpled (cross-drilled) then avoid measuring at those areas as they can alter the results of the measurements.

Driving Tips

The simplest and most preventative way to keep rotors and the braking system as a whole last a long time is to obey the rules. By that I mean driving according to the speed limit as driving faster not only is dangerous but it is also more taxing as this also makes braking more abrupt.

Being aware of how traffic is moving can help you plan ahead of time. This can be beneficial for the rotors as you will know exactly when to slow down and apply the brakes instead of doing so unexpectedly.

Make sure you always use your right foot to accelerate and brake. Hitting the brake with the other foot whilst you still haven’t lifted your right foot from the gas pedal requires more effort from the brakes. This wears them more, thus shortening their lifespan little by little every time you do it.

Go by the three-second rule. Find an object of any kind and count to three when you start moving – if you get to three before you pass the object, you are good, if not, then you need to have more space when stationary. This is a defensive style of driving that guarantees safety and less stress on your braking system.

How to Measure Disc Brake Rotor Size?

If you need to get your rotors replaced, you need to measure them in order to get the correct size rotors. You cannot get smaller or larger rotors as they need to match the size the manufacturer set to fit on the wheel hub flange. Usually you need a new rotor when there is excessive run out, or severe warping. Measure the longest possible width of the rotor from the outside edge – note that this is not the same as measuring the width of the rotor. This will help with compatibility and guarantee that you get an efficient part.