Brake Pad Thickness: Minimum, New, and Ideal Thickness (Chart Included)

How thick should brake pads be? What is the minimum legal thickness of brake pads, and what about the ideal thickness? Here's a guide that includes a chart.

With worn-out brake pads, the brakes won’t function at all. The only way you’ll be able to bring the car to a halt is with engine braking and, when necessary, the emergency brake.

Fortunately, you shouldn’t ever reach this point. Routine checks and metal warning layers give you months of alerts.

Brake pad thickness should be checked as often as reasonably possible. It is a crucial part of stopping your car, after all.

In brief, brake pad thickness is essential to keep an eye on. In this straightforward guide, I’ll explain brake pads’ minimum, new, and optimal thicknesses. I’ve also included a custom chart.

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Key Takeaways: Brake Pad Thickness

  • The lowest recommended brake pad thickness is 3 mm.
  • Brake pads thinner than 3 mm are considered dangerous by mechanics.
  • The lowest legal brake pad thickness is (usually) 1.6 mm.
  • A new front-wheel brake pad should be about 12 mm.
  • A new rear-wheel brake pad could be between 8 and 10 mm.
  • Use brake pad thickness gauges or simple tools to measure them.

Table of ContentsShow

How Do Brake Pads Work?

Brake repair

Brake pads have a metal backing plate with a high-friction surface attached to them. Each wheel has two pads – one for the outside and one for the inside. They fit inside the brake calipers.

When you press the brake pedal, hydraulic brake fluid forces the piston (or pistons) in the caliper towards the spinning rotor. Its rough surface pushes into the revolving rotor face.

As the surfaces touch, resistance slows the rotor down. In turn, this reduces the rotational velocity of the wheels and decelerates (or halts) the car.

Note that brake pads and rotors get extremely hot due to all the friction, especially during hard braking.

That’s why you see racecar rotors glowing orange as they approach corners. If they get too hot, you’ll experience what’s known as brake fade: when the brakes stop working properly. Many modern rotors are ‘vented’ to counter this. 

How Thick Should A Brake Pad Be?

Symptoms Of Worn Brake Pads

A significant brake pad makes all the difference when stopping. The more material there is, the easier it is to absorb and dissipate the frictional heat.

In contrast, if your pads go below the suggested brake pad thinness, they’ll get too hot. Your car will have significantly reduced stopping power.

This is dangerous to yourself, your passengers, and other road users (including pedestrians).

In severe cases of neglect, the frictional material will completely wear away. This leaves the metal backplate to press against the rotor face.

If this happens, you’ll hear a horrible screeching noise (far worse than the shrill warning noise). The car will also struggle to stop.

Check out this brake pad measurement chart for a clear visual to explain what’s ideal, acceptable, and dangerous.

Brake Pad Thickness Chart

What Is The Ideal Thickness Of Brake Pads?

How thick should brake pads be? Ideally, 6 mm or more. Once you go below 6 mm, the brake pads cease performing so efficiently (in most instances).

They’ll be fine for a while – there’s usually no need to replace them. Follow your mechanic’s advice.

When your brake pads wear down to 3 mm, they should be replaced. It’s not the legal limit, indeed. However, most seasoned mechanics will agree that this is the minimum safe brake pad thickness.

What Is The Legal Minimum Brake Pad Thickness?

Realistically, you must always keep your brake pads above 3 mm.

The regulated minimum thickness for the steering axle is 1.6 mm for hydraulic disc brakes and 3.2 mm for air brakes. As usual, measure this from the steel backing plate to the lowest point of the pad.

It may be the minimum legal requirement, but that doesn’t mean you should let your brake pads wear down to this point. At 1.6 mm, your brakes will be perilously inefficient.

Brake manufacturers will tell you when the pads and rotors need to be replaced. It’s prudent to follow their recommendations.

When Should I Check Brake Pad Thickness?

changing brake pads

You should check brake pad thickness about approximately 5,000 miles or a few times per year. Mechanics should inspect the brakes every time you visit. It’s best to inquire specifically to make sure.

Generally, you should expect brake pads and rotors to last an extended time. 40,000 miles (depending on your driving habits and techniques) is a sensible average.

If you hear a shrill screeching noise from your wheels, it’s almost certainly the brake pads. This is an indication that they’ve reached the minimum allowable thickness.

Take your car to a technician immediately and have the brakes replaced.

It’s advised to replace pads and rotors at the same time.

How Do You Measure Brake Pad Thickness?

Brake discs. Assessment of technical condition, thickness measur

Measuring brake pad thickness is a comparatively simple job, but it often involves removing the wheels. You’ll need a jack, axle stands, breaker bar, wheel nut sockets, and a torque wrench (at least) for this.

Take a measuring gauge tool. You’ll need to find the particular instrument that snugly fits between the brake pad’s backing plate and the rotor face.

This evaluation is your brake pad thickness.

If you’ve taken the brake pads off, you can use a more widespread method. Mechanics often use a tire tread depth gauge against the backing plate to measure pad thickness. Take measurements in numerous locations.

Torque the wheel nuts back up to the proper level when replacing the tires.

Note: It’s also possible to measure brake pad thickness without taking the wheels off. However, this can be challenging to do to any degree of accuracy. It’s almost impossible to measure the outside pad unless you have alloy wheels. You might be able to check the inside one by turning the steering wheel to full lock and getting underneath the vehicle.

Do Some Brake Pads Last Longer Than Others?

brake pads with brake disks in the background

Not all brake pads are created equally. It’s not accurate in every case, but you’ll generally receive what you pay for.

Budget brake pads tend to be made from cheaper materials that are less effective at dissipating thermal energy. Pricier parts should perform much better.

That being said, watch out for branding. You don’t need to get the finest brake brand – most people can’t see them anyway. Instead, focus on the optimal brake pad materials, ensuring they’re OEM.

High-performance brake pads aren’t always necessary, especially if you drive a small, light hatchback. However, look for ceramic or metallic options for the best stopping power. Ceramic pads are most effective under stress since heat is less of an issue. Still, they’re often expensive, and you’ll need to purchase high-quality rotors to match. As such, metallic brakes are the most frequent choice for daily drivers.

You can also find organic brake pads. Previously made from asbestos (no longer!), these choices are generally inexpensive. They are affordable but may not be as long-lasting or effective, yet they are still lawful and will work reasonably well.

How Thick Are New Brake Pads?

New brake pads should be 12 mm thick. If you’re replacing the brakes on a rear wheel, you might find that the pads are marginally thinner (8 to 10 mm).

If you’d like to check for yourself, you can measure brake pad thickness before inserting them into the caliper. A basic rule or tape measure will do.

You can see these measurements on the brake pads thickness illustration above.

Why Won’t My New Brake Pads Stop The Car?

Check out the guide below for additional information on the expenses of changing brakes.

Related:

When you replace the pads (ideally with the rotors), you might notice that the vehicle struggles to stop. This occurs when the brake pads are ‘carving into’ to the rotors, creating a channel in which they’ll soon settle.

There shouldn’t be anything faulty with the brake pads themselves.

The mechanics should take the car for a test drive around a guarded, vacant car park (or something similar) to bed them in. They’ll slam the brakes on several times, forcing the pads to dig into the rotor.

If, when you get your car back, it still feels like it’s straining to stop, take it to a secure but secluded location. Do this yourself a few times.

The halting capability should soon be back to normal.

Is the issue persisting? The brakes might need bleeding, or the calipers could need replacing.

Conclusion

A car with a yellow brake caliper

It’s always imperative to ensure your brake pads are in good condition. They aren’t parts you usually look at, so having them specifically inspected is a must.

Once they get below 6 mm, consider having them swapped out for fresh ones. Never let them go below 3 mm.

Certainly, the new pads ought to measure 12 mm, and they should last for a couple of years. They could require substitution sooner if you usually apply substantial force to brake regularly.

The best way to ensure your brake pads work well and last for an extended time is to drive and brake smoothly. Only slam the pedal down if emergency calls for it.

To take a brake pad measurement, get yourself some measuring gauge tools. These are by far and away the most straightforward way to do it.

Brake pad replacement is comparatively inexpensive as far as automotive jobs go. It should be done whenever essential to keep your car and everyone in and around it safe.

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Benjamin Kitchen

Ben is an IMI-qualified light vehicle technician from England with experience in a fast-fit garage. He aims to help drivers worldwide with common automotive problems. You’ll often find him working with his 1.2 Vauxhall Corsa. It may have a tiny engine, but in eight years it's never once let him down!