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How-to guide

How to check and replace disc brake pads

Check disc brake pad wear against Park Tool, Shimano and SRAM limits, then remove and fit new pads on hydraulic or cable disc calipers.

Last edited Nov 8, 2026 by Pedalwise team Edit History Add a subpage

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Difficulty
Moderate
Time
20 to 45 minutes

Parts

This guide covers checking disc brake pads for wear and swapping them on common hydraulic and cable-pulled calipers. Pads are held in different ways by different brands, so keep your brake's manual handy. On a scooter with disc brakes, use your scooter's manual to see how to reach the caliper. For an overview of brake problems, see e-bike brakes.

Don't ride a bike with weak or unreliable brakes. Shimano says that if the lever feels sluggish or gives no resistance, stop using the brakes and see a professional (Shimano dealer manual).

E-bikes are usually heavier than regular bikes and speed up quickly, so Bosch advises learning how yours handles and brakes, and checking the brakes regularly (Bosch eBike guide).

Before you start

  • Find your brake's make and model. Shimano's dealer manuals cover pad fitting for its brakes (Shimano dealer manual), and SRAM's user manual covers its pads (SRAM user manual).
  • Get the right pads. Park Tool suggests asking a shop, checking the caliper maker's site, or matching the shape of your old pads (Park Tool).
  • Pick a pad material. Park Tool compares organic, metallic and semi-metallic pads: organic pads give the strongest initial bite and are easiest on rotors, while metallic pads last longest in dry and wet riding. Some rotor and pad pairings don't work together, so check the warnings on the parts or packaging (Park Tool).

1Check pad wear

  • Let the brakes cool before you measure (Shimano dealer manual).
  • Measure the friction material, not the metal backing. Park Tool's general rule is at least 1 mm of pad material, and three stacked business cards make a rough 1 mm gauge (Park Tool).
  • Maker limits differ. Shimano says replace its pads at 0.5 mm or less (Shimano dealer manual). SRAM says replace when pad and backing plate together measure 3 mm or less, and to check monthly (SRAM user manual).
  • A metal on metal grinding sound means the pads are worn out. Shimano says replace them right away to avoid rotor damage (Shimano maintenance tips).
  • Squeal, extra lever effort, or a dark rotor and pads that smear when touched can mean the pads are contaminated (Park Tool). Oil on the pads is a reason to replace them (Shimano dealer manual).

Photo needed: A worn pad next to a new pad, showing how much friction material is left on each. Add one

2Remove the wheel

3Take out the old pads

  • Note how each part sits before you remove it, because fitting is the reverse (Park Tool). A phone photo helps.
  • Park Tool describes the common retention styles: a cotter pin you straighten and pull, a pin clip that comes off before the pin, magnets, clips that can need real force, and springs that come out with the pads (Park Tool).
  • Shimano calipers use a snap ring or split pin on the pad pin (Shimano dealer manual).

Photo needed: An open caliper with the pad pin, clip and spring laid out in order on a clean rag. Add one

4Reset the pistons or adjusters

  • Hydraulic: press the pistons back with a flat, non-marring tool such as a piston press or tire lever (Park Tool). Shimano says clean the pistons first and never push them with a sharp tool (Shimano dealer manual).
  • Some Shimano calipers have ceramic pistons, so press evenly (Park Tool).
  • Mechanical: turn the pad adjuster counterclockwise until it stops (Park Tool).

5Fit the new pads

  • Reverse the removal order. Springs can have a right way up, usually shown on the pad packaging. Press pads and spring in until they click, which can take a few tries (Park Tool).
  • Bend a cotter pin well so it can't slide out, and refit any pin clip. A threaded pin goes to its torque spec (Park Tool). Shimano gives 2 to 4 Nm for its pad pin bolt (Shimano dealer manual).
  • A little side to side wiggle in fitted pads is normal (Park Tool).

Photo needed: New pads seated in the caliper with the spring in place and the pin secured. Add one

6Refit the wheel and set the pads

7Bed in and test

Videos

How to Replace Bicycle Disc Brake Pads from Park Tool: Removes worn pads, resets the pistons and fits new pads and the retaining pin, then checks the lever before riding.

When to get a pro

Sources

Stuck after these checks? Find a shop near you.

Need a pro?

If these steps didn't fix it, find a shop near you in our partner network. For battery or wiring trouble, look for shops marked Battery and electrical.

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