When to Replace Brake Pads (Minimum Brake Pad Thickness)

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.

brake pad thickness measuring tool
OTC brake pad gauge (click image to buy)

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

measuring brake pad material
Lisle 81850 brake gauge (click image to buy)

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

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.

How to Check Brake Pad Thickness

Tools Required:

  • Brake pad gauge (like this or this)
  • Wheel lug wrench (like this)
  • Jack and jack stands (if necessary)

Steps:

  1. Park the vehicle is on a level surface and allow the engine to cool down. Apply the parking brake for safety.
  2. Loosen the lug nuts or bolts on the wheel you’ll be inspecting and raise the vehicle using a jack. Place jack stands under the designated jacking points (see your owner’s manual) for stability. Remove the wheel for better access to the brake assembly.
  3. Locate the brake caliper, which is the large, clamp-like device that houses the brake pads and pistons.
  4. Inspect the brake pad without removing it from the caliper. Look at the outer edge of the pad, where you should see the friction material.
  5. Using the brake pad gauge, measure the thickness of the friction material. Place the gauge on the pad and record the measurement.
  6. Compare the measurement to the manufacturer’s recommended minimum thickness, which is typically around 3-4mm. If the brake pad is at or below this thickness, it’s time for a replacement.
  7. Repeat the measuring process for the inner brake pad (each wheel has 2 brake pads).
  8. Reinstall the wheel and tighten the lug nuts to the manufacturer’s specified torque.
  9. Repeat the process for each wheel.

Interpreting the Results:

  • If the brake pad thickness is above the minimum recommended level, your pads are still in good condition and no further action is needed. However, if you’re getting close to the minimum thickness, start making plans for pad replacement.
  • If the thickness is at or slightly below the minimum, plan to replace the pads soon to avoid potential brake system damage or compromised braking performance.
  • If the thickness is significantly below the minimum or the friction material is worn down to the metal backing plate, replace the pads immediately. Continuing to drive with excessively worn pads can damage your brake rotors and compromise your vehicle’s safety.

Factors That Affect Brake Pad Wear

There are several factors can influence the rate at which your brake pads wear out, ultimately determining how often they need to be replaced. Understanding these factors can actually help you extend the life of your brake pads and allow you to better plan for the cost of brake pad replacement.

  • Driving Habits:  Driving style plays a major role in brake pad wear. Frequent hard braking, riding your brakes, and rapid acceleration with abrupt stops put more stress on the brake pads, causing them to wear out faster. Smooth, gradual braking, maintaining a safe following distance, and not driving with your foot resting on the brake pedal can help reduce brake pad wear.
  • Vehicle Type and Weight:  Heavier vehicles, such as SUVs and trucks, require more braking force to stop, which can lead to faster brake pad wear compared to lighter passenger cars. Additionally, high-performance vehicles with powerful braking systems may experience more rapid brake pad wear due to the increased friction and heat generated during braking.
  • Environmental Conditions:  Driving in dusty, muddy, or sandy environments can accelerate brake pad wear. Abrasive particles can become embedded in the brake pads, causing them to wear down more quickly. Exposure to salt in coastal areas or on winter roads can also contribute to faster brake pad deterioration.
  • Brake Pad Material:  The quality and composition of the brake pad materials can significantly impact their lifespan. Higher-quality brake pads made from advanced materials, such as ceramic or high-performance composites, often last longer than lower-quality, budget-friendly options.
  • Driving Terrain:  Frequent driving in mountainous or hilly areas that require constant braking can lead to faster brake pad wear compared to driving on flat, straight roads. The increased use of brakes to control speed on descents puts additional strain on the brake pads.
  • Vehicle Maintenance:  Proper vehicle maintenance, including regular brake system inspections and servicing, can help identify potential issues that may contribute to premature brake pad wear. Factors such as misaligned wheels, stuck brake calipers, or worn suspension components can cause uneven or accelerated brake pad wear.
  • Towing:  Vehicles that frequently tow heavy trailers or haul substantial loads put extra stress on the braking system (especially in hilly areas), leading to increased brake pad wear. The added weight requires more braking force, which can cause the brake pads to wear out more quickly and even overheat.
Kevin

14 thoughts on “When to Replace Brake Pads (Minimum Brake Pad Thickness)”

  1. Do you know of a safety law that requires Dealers to replace brake pads before selling a used vehicle? Also do you know what the limit is for pad thickness? Thanks

    Reply
    • I have never worked at a dealership, so I am not sure. Your pad thickness limit will vary depending on the car and how it’s used, but it’s generally around 2 to 4 mm. If the car sees heavy braking and very high temperatures, the rule of thumb is that the pad should be no thinner than the backing plate.

      Reply
  2. “Get them replaced at the dealership that sold you the vechile”. Absolutely not necessary , you will pay top dollar for no good reason. Excellent after-market parts are available that meet or exceed OEM quality.

    Reply
    • You want a clean mating surface for the new brake pads, especially when you change pad material. Each time you turn rotors, you reduce the rotors’ thickness and their ability to dissipate heat. Rotors have a minimum thickness spec, but they’re often so cheap you may as well replace them while you’re in there.

      Also, rotors often (but not always) have excessive runout at the end of brake pad life. This leads to the pulsing you feel in the brake pedal when you stop.

      Reply
  3. Was looking for info in deciding whether or not to replace my brake pads. Your article provided the answer to my question. Thanks very much.

    Reply
  4. I learned alot from this especially about the components of break pad not only the required thickness but the risky size in mm of a warned out pads

    Reply
  5. I’ve learned a lot from your blog. I never tried to change brake pads by owns. But i’ll try next time with your inspiration. Thanks a lot.

    Reply

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