When it comes to receiving attention, brake rotors often get overlooked. Riders are more concerned with how swiftly their bike accelerates than with how quickly it slows down. But, after enough kilometres and years, all motorcyclists confront the same task: changing their brake rotors.

Motorcycle brake rotors should be replaced when they are worn to a specific extent, damaged, or distorted. There is no set time frame because it is very dependent on the type of bike you ride, the type of rotor you use, the type of riding you do, how rapidly you rack up miles, and so on. The most important thing to remember is that if you detect a change in braking performance while riding, such as a mushy lever, brake chatter, or squeaking/grinding while braking, you should inspect your rotors and other system components. We’ll go over some particular items to check for that may suggest it’s time to replace your rotors.

There are two techniques to identify if you need new brake rotors. One method is to test while riding, while another is to perform a basic test in your garage.

If you discovered you needed new brake rotors while riding, it was probably because your brakes began pulsing. When brake discs overheat, they distort. This warping means that your brake pads can’t apply consistent pressure all the way around your brake disc, resulting in uncomfortable and dangerous brake pulsing. If your brakes are pulsing, it is necessary to replace the rotor.

The second technique to evaluate whether you need new brake discs is to simply get down and look. You’ll be looking at two things: rotor thickness and surface condition of your brake rotor. All rotors have a minimum thickness, and by measuring it with a micrometre or calliper, you can quickly and easily determine whether your disc is thick enough. Keep in mind that your brake pad should not come into contact with the disc’s outermost edge.

If your rotor measures at or below the manufacturer’s minimum thickness. Why is this such a big deal? It is about heat transmission. As the rotor material wears away, heat transfer from one side to the other accelerates, transferring more heat to the brake pads and braking fluid. When your braking fluid heats up, the brake lever becomes mushy and responds slowly.

When inspecting the surface quality of your braking rotors, you will be looking for areas where the pads have created friction. You’re looking for irregularities. It is usual to see little grooves or lines and a small bit of texture on its surface, but any grooves or nicks that are excessively prominent should be regarded a red flag.

Scoring occurs when microscopic grooves form on the rotor surface, which is often caused by debris being lodged between the pads and rotors. To inspect your rotors, first remove them from your bike and thoroughly clean them (how to clean brakes). Once clean, run your fingertip over the rotor’s surface, beginning at the outside edge and working your way to the centre. If you feel any lumps or grooves when your nail goes over the surface (which may also be visible to the eye), this deteriorated friction surface can reduce brake performance – it’s time to replace!

I have heard of disc warping, what is it?

When the rotor loses its parallel surface and warps to one side or another its called warping. It happens mostly more in racing situations, where the rapid heat cycles and hard braking pressure cause the rotor to bend over time. Warped rotors do not operate properly due to irregular contact with the brake pads and should be replaced promptly.

So do I need new brake pads when I change my rotors?

In brief, it depends. If your brake pads are still relatively new and equally worn, you should have no issue fitting them on your new rotors. They will perform admirably once bedded in. However, if your previous rotors have devastated your brake pads, leaving them uneven and gouged, you should start over with new brake pads to ensure even wear patterns and peak performance.

Do I need to do anything else?

Bedding your rotors and pads is crucial. Your new brake pads and rotors may feel smooth to your fingers, but they are actually coated in microscopic ridges and grooves. The bedding procedure helps to synchronise these surfaces so that your rotor and pads lay absolutely flush, generating the most friction and stopping you as swiftly as possible. The bedding procedure involves heating your brakes and spreading a thin coating of brake pad material across your rotor. Failure to complete the brake bedding procedure can lead to uneven distribution of brake pad material, resulting in brake pulsing.

Is there any maintenance required after changing my rotors and pads?

Riding in dirt and slush may cause dirt and grime to accumulate around the disc rotor and calliper assembly. If you observe a steady decrease in stopping power on your motorbike, it could be due to the filth that has found its way into the braking system. Although a water jet spray should suffice if you want to thoroughly clean the rotor, use a specialised brake cleaner. You can also use isopropyl alcohol-based solutions, but avoid petrol, kerosene and diesel because they are all petroleum-based and may leave oil residue, significantly lowering braking efficiency.