WHEN TO REPLACE DISCS & PADS
Author: Sarah @ MetalGear
The correct brake discs and brake pads are determined by the original equipment manufacturer (OEM). If you are buying aftermarket you must ensure that the measurements/specifications match your model.
Below is a simplified guide to help you determine if you need to replace your brake discs and pads.
Changes to performance as well as a visual inspection of your brake disc is vital to determining if they need replacing. Visual inspections should be carried out before each ride. The minimum thickness is the minimum safe working thickness of a brake disc rotor at which it must be replaced. This can be found in the manufacturer workshop manual or printed on your brake disc.
Proper measurement of the thickness of discs can only be done with a micrometer. A vernier caliper is not as precise as most discs develop a “lip” meaning you are not measuring the mid-point of the braking surface. A micrometer would give you the most accurate reading. You place it towards the middle of your braking surface and go around measuring at about 4 different points. Discs have a habit of wearing more in the middle of the disc rather than the outer which is why it is important to use the correct tools and take a few measurements at different points of the brake disc.
For floating brake discs, if you notice excessive movement in the rivets/buttons these must be inspected and most likely replaced as soon as possible. Do not lubricate the buttons or rivets. This has been a workshop rumour that has been circulating for years and is not correct. A major issue to lubricating buttons or rivets is that once the disc starts spinning, the lubricant will leak onto your braking surface compromising the performance. In a nutshell: Lubricant on brakes = no brakes. If you are in doubt, bring your floating disc to a Technician for them to assess and advise if it needs replacing.
Changes to performance as well as a visual inspection for delaminating or separating of the brake pad compound from the backing plate is the best way to tell if your pads need replacing. Separation from the backing plate can happen to old pads when corrosion of the binding material occurs. Checking the pad thickness is also vital; pads should be replaced as soon as you have a few mm thickness remaining to avoid ‘metal on metal’- that is the backing plate of your brake pad grinding on your brake disc when braking. We always recommend that you refer the manufacturer/workshop manual for your model as wear limits can differ between manufacturers. Additionally if you notice squealing or grinding sounds when using your brakes whilst riding could be a sign something needs replacing.
We always recommend that you replace brake discs and brake pads at the same time. Both surfaces of your brake pads and brake disc should be faultless to ensure long life of your disc. MetalGear Brake pads come in three different compounds; a choice for your own riding style and braking preference. All MetalGear Brake Pads are tested to ensure perfect harmony with MetalGear Brake Discs.
If you're unsure, MetalGear has an onsite Technician that can inspect your brake disc and pads and advise if either needs replacing. Feel free to drop by, click here for location and trading hours.