Sparesbox Blog

When To Change Your Brake Rotors

By Mitch Babbs

Tue Mar 02 2021

Waste not, want not. We all want to get the most out of our brake rotors, but at a certain point you've gotta know when to keep cruising with the ones you've got, and when to move on to some shiny new ones. First of all, what exactly are brake rotors (or disc brake rotors)?

Don't stress if you don't know. Remember, it's 5 minutes of feeling a fool when you ask a silly question, and a lifetime if you don't. Naturally, they're a part of your car's braking system. They're the big flat doughnut (with a smaller doughnut attached), and when you press your foot on the brake pedal, your brake pads clamp down on your brake rotors, creating resistance that stops your wheels from turning.

Now, how long your brake rotors are going to last is dependent on a number of different factors. Some, but not all of these factors:

  • What type of brake pads you're using
  • How aggressively you drive, your braking style, etc.
  • How hard the material your brake rotors are made of is
  • Environmental factors; moisture, road salt/grime etc.
  • Your brake rotors' cooling efficacy

As a general rule, most cars will burn through 2 sets of brake pads for each set of brake rotors. Best to check your rotors once every 15,000km.

So what signs are you looking for in your brake rotors that tell you that you need to change them? It will normally be one of two things: excessive rotor thinning, or 'disc warp'.

In both cases, the brake rotors themselves can become unsafe for use. When they're under their minimum recommended thickness, they can be prone to cracking and can struggle to dissipate heat. With disc warping, the uneven spread or dissipation of heat can create peaks and valleys on the disc where brake pad material can collect, resulting in a vibration that you can feel while pressing the brake pedal.

Above: an example of disc warp on an old brake rotor.

Now that you've diagnosed the problem and realised you need to replace your brake rotors, it's time to face the next obstacle. What are you going to replace them with?

Broadly speaking, brake rotors fall into two categories: OE replacement rotors (designed to simulate that new-vehicle braking feel, operating quietly and without hassle in regular driving conditions) and performance brake rotors.

Performance brake rotors can be further split into their suitability for street, track, or hybrid applications. Brake rotors intended for street use will sometimes feature drilled holes in their faces, aiding in heat dissipation, with a shallower profile and showcar-like look for the aesthetically inclined. Slotted rotors are best suited for track use, where the dissipation of heat is king, ensuring far less hot-spotting or glazing than any other form of brake rotor.

Finally, who to trust when it comes to picking out your replacement brake rotors. For each main category we've got some personal favourites we'd like to recommend.

OE Replacement Rotors:

  • DBA: Disc Brakes Australia are an Australian brand that manufactures a great range of high-quality rotors for everyday applications. Their new range of En-Shield brake discs also come with the added benefit of corrosion resistance on non-wearing surfaces.
  • RDA Standard Brake Rotors: Australian-owned, made & manufactured, RDA rotors are one of the most trusted names in braking for good reason, with expansive ranges covering the whole gamut of driving applications.
  • TRW: TRW are pioneers in the field of electronic braking systems, offering a range of forward-thinking solutions to ensure your brakes are at their best. They offer a range of everyday brake rotors and pads.

Performance Brake Rotors

  • DBA Slotted and Cross Drilled Brake Rotors: Created for the performance brake market in Australia. Designed locally for harsh Australian conditions they are the ideal upgrade for customers looking to improve braking performance for street or track driving.
  • Zimmerman Rotors: An outstanding choice for daily drivers that want to maximise the performance of their street car. Every Zimmerman brake rotors comes precision-drilled, and is made from high-carbon iron or steel to ensure incredible resistance to heat and the pressures of high-performance driving, offering the ideal rotor for use on the track and the street.

And the best news yet is that for a very limited time, you can get up to 20% off a huge selection of brakes: rotors, pads, drums and tonnes more. Just use code 'BRAKE20' at checkout!