Sparesbox Blog

Refreshing your Brake Disc Rotors

By Brad Nash

Thu Jul 02 2015

Having properly functioning brake disc rotors is key to making sure you’re getting the friction you need to stop safely and effectively on the road. Brake disc rotors are essentially the discs that spin with the wheel while you’re driving. When you press the brake pedal, the brake pads compress upon the disc rotor, generating friction and converting the kinetic energy of your car’s movement into heat energy. This slows the vehicle’s momentum, bringing it to an eventual stop.


Brake disc
There’s something unsettling about this gif, but it’s the best the internet could offer. Source: Wikimedia


As you could imagine, the brake disc rotors take a tremendous amount of punishment; even more so if you’re using a high-performance, high-friction brake pad. As such, to keep your stopping power at it’s best you want to make sure your disc rotors are free of wear, and replaced at regular intervals.


How Do I Feel When My Disc Rotors are Getting Past It?


Most of the time, you’ll be able to tell how your disc rotors are going just by being a conscious driver. When the brake disc rotors are worn, the pads aren’t able to get a consistent grip, leading to vibrations that you’ll feel upon pressing the brake pedal. The same problem will also cause the brakes to squeak in some cases and produce a less responsive, spongey feeling when you press the brake pedal. Any one of these three things (along with a general drop in braking performance from what you’re used to) can all be indicators of worn brake pads.


Are My Brake Disc Rotors Too Thin?


Simply measuring the thickness of the disc rotors is a major giveaway on whether your disc rotors are starting to wear too much. Once they get past a certain point (like these ones below), they’re going to need replacing. Consult with the manufacturer of your brake disc rotors for their recommended minimum thickness. If you’re not sure, any mechanic will measure them as part of a standard check up. As the brake pad only presses against a certain part of the disc rotor, they’ll be a different width along the top than they will at the their base. This also creates a bit of a lip at the very top of the disc rotor.


Brake Disc


Machining or Replacing? The Great Trade-Off


In some cases, as you can see below, they may just need machining. This is performed by a mechanic or a specialist brake shop on a specifically designed brake lathe. During the process, a small layer of metal is machined off of the top of the disc rotor, getting rid of the grooves and exposing a fresh surface of metal underneath. This allows the brake pad to get more grip on the disc rotor, rejuvenating your stopping power. Doing this will reduce the life of the disc rotor, and also take more time than simply replacing it. For many common cars, it will generally be more convenient to throw a new set of disc rotors on.


Brake disc


Making sure your brakes are at peak performance is one of the easiest ways of keeping you and your passengers safe. If you want to simply refresh your stopping power or make the upgrade to a more performance oriented feel, fresh brake disc rotors should be one of your first steps. When replacing your pads or brake disc rotors, make sure you change your brake fluid as well, as this can be a key cause of your brakes underperforming, and no amount of part replacements will make that much of a difference if your brake fluid isn’t where it should be. You can shop our huge range of braking products here.