(Updated on May 18, 2020)
Brake discs are the modern-day equivalent of the brake shoes that were used in the older drum braking system. Nowadays, most vehicles use a disc braking system to allow the driver to slow down and stop their vehicle.
This system is comprised of a brake caliper which contains pistons and brake pads. There is also a spinning disc that rotates along with the wheel when the vehicle is moving. The caliper applies pressure to the brake pad, causing the pad to push against the brake disc.
The friction created between the brake pad and brake disc causes the wheel to slow down its rotation. This happens whenever the driver steps on the brake pedal.
The materials used to construct brake pads include steel backing plates, shims, friction materials, rubberized coatings, and thermal insulation coatings. These are strong materials, but they are not strong enough to last forever.
There will come a time when your brake pads will need to be replaced. Since the brake pads get used whenever you step on the brake pedal, they tend to wear out after about 50,000 miles.
However, you can get a longer life out of your brake pads if you use ones which have the right thickness. We will go over thickness levels below.
Minimum Brake Pad Thickness
When your brake pads rub up against the discs, it wears down their friction material. When we measure the thickness of a brake pad, we are measuring the thickness of this material.
If your friction material were to get too thin, then it would not be able to slow down your vehicle quickly after you step on the brake pedal. If the material dissipated completely, then your brakes would ultimately fail.
You should follow the manufacturer’s recommended minimum brake pad thickness. In most cases, you’ll want to replace brake pads when they get down to about 3mm. While you can sometimes get away with 2mm, that is right around where the metal wear indicator gets exposed and causes a squealing sound against the disc.
Keep in mind that the lower the thickness, the worse the pads deal with heat and are at greater risk of cracking. Therefore, anywhere from 3mm to 4mm is the recommended thickness to replace brake pads in most cases.
You may be able to get away with slightly less thickness, but certainly nothing less than 2mm. At that point, braking performance can suffer and damage to your brake rotors is more likely.
Read also: How Long Do Brake Pads Last?
Recommended Brake Pad Thickness
If you are purchasing new brake pads, then you will want their friction material to be around 10 to 12 millimeters. This is the standard thickness size that you will see for most new brake pads.
It should take about 50,000 miles (more or less) for the thickness to 3 to 4 millimeters. It all depends on how aggressively and frequently you use your brakes so while 50k miles is average for many, 20k miles may be more realistic for some. Also, keep in mind that some brake pad materials last longer than others.
While you can purchase new brake pads at your local auto parts store or online, the best way to get the right brake pads is to get them replaced at the dealership which sold you the vehicle.