What Are Brake Rotors And Why Are They Important?

If your GM vehicle has a disc braking system, you’ll find a rotor behind each of the four wheels. Rotors help stop your car, which is a really important task.

Let’s talk about how brake rotors work and why they play an important role in stopping your vehicle.

What is a Brake Rotor?

An OEM GM brake rotor is a metal disc that’s about a foot wide, give or take a few inches. It’s attached to the hub assembly (and therefore the axle). Here's what a typical rotor looks like:

Gm rotor oem

OEM Part #19174912: specifically designed for select Blazer, S10, GMC Jimmy, Sonoma, and Bravada models

The dimensions of a brake rotor vary between GM models. Heavier vehicles typically have bigger brakes. For example, the 2015 GMC Silverado has rotors with the following dimensions:

  • 13” diameter
  • 7.7” wide offset (the middle part where the bolts go through)
  • 30mm (or 1.181”) thickness

Also called brake discs, rotors are attached to both the axle and wheels via the wheel hub assembly and lug studs. That means the wheels move along with the rotors. When the rotors stop, the wheels stop.

How do Rotors Help Stop Your Car?

There’s a caliper wrapped around the rotor. When you hit the brakes, the piston makes the caliper squeeze the brake pads inwards against the rotor. The friction material from the pads generates friction and high heat when squeezed against the rotor. The heat and friction stops the rotor from turning in a matter of seconds. Below, you'll find a gif of how the process works. The spinning part in the middle is the rotor. Notice that it comes to a complete stop when the caliper squeezes the pads against it.


Do Rotors Last Forever?

No. Rotors typically last about 30K-70K miles. The longevity of your rotors depends on your driving style and the weight of your vehicle. When your rotors start to go bad, you’ll know. Some signs of a bad rotor include:

  • Squealing or squeaking noise
  • Vibrating when the brakes are applied
  • Longer stopping distances

You can diagnose failing brake rotors by following the steps outlined in this guide

You can also replace your GM's rotors yourself. It's a really easy and straightforward process. You'll not only save a lot of money on labor, but you'll also get to save money on replacement rotors by ordering genuine OEM rotors from us at wholesale pricing. Look up your GM model here to see if we have rotors available for you at rock bottom prices!