How to Replace Disc Brake Pads on a Mountain Bike
Disc brake pads wear down gradually — and most riders don’t notice until braking performance drops noticeably. This guide shows you how to check your pads and replace them yourself.
How do I know when my brake pads need replacing?
Look through the caliper at the pad material. Most disc brake pads have 3–4mm of usable material when new. Replace them when the pad material is down to around 1mm or less.
Other signs your pads need attention:
- Braking feels less powerful or requires more lever pressure than usual
- A squealing or grinding noise when braking
- The lever pulls closer to the handlebar than it used to
- Visible scoring or grooves on the rotor surface
Before you start — check pad compatibility
This is the most important step. Shimano alone uses several different pad shapes across its brake range, and fitting the wrong pad can damage your caliper or leave you with no brakes at all.
Download our free Bicycle Disc Brake Pad Compatibility Handbook — it covers the most common Shimano, SRAM, and own-brand brake systems and tells you exactly which pad you need.
👉 Download the free Disc Brake Pad Compatibility Handbook
What you’ll need
- Replacement brake pads (correct type for your caliper — see handbook above)
- A flat-head screwdriver or 2mm Allen key
- Needle-nose pliers (helpful but not essential)
- A clean rag
- Isopropyl alcohol (for cleaning the rotor)
Which pads does Peak Bike Station stock?
We stock Shimano B05S resin brake pads — compatible with Shimano MT200, MT400, MT500, and several other entry-level and mid-range Shimano hydraulic brakes. These are the most common pads for mountain bikes sold in the UK.
Not sure if B05S is right for your bike? Check the free handbook above.
Step-by-step: replacing disc brake pads
Step 1 — Remove the wheel
Take the wheel out of the dropout. This gives you clear access to the caliper and makes the job much easier.
Step 2 — Remove the retaining pin or clip
Most Shimano calipers use a split pin or a bolt to hold the pads in place. Use a flat-head screwdriver or Allen key to remove it. Keep it safe — you’ll reuse it.
Step 3 — Remove the old pads
The pads will slide or pull out of the caliper. Use needle-nose pliers if they’re stiff. Note which way they came out — the new pads go back in the same orientation.
Step 4 — Push the pistons back
Before fitting new (thicker) pads, you need to push the caliper pistons back to create space. Use a flat tyre lever or the old pad itself — place it between the pistons and gently press them back until flush. Do this carefully and evenly.
Worth knowing: pushing the pistons back forces brake fluid back into the reservoir. If your reservoir is full, some fluid may overflow — have a rag ready.
Step 5 — Clean the caliper and rotor
Wipe the inside of the caliper with a clean rag. Clean the rotor with isopropyl alcohol — never touch the rotor or new pad surfaces with bare hands. Skin oils contaminate the pad material and cause squealing.
Step 6 — Fit the new pads
Slide the new pads into the caliper in the correct orientation. Refit the retaining pin or clip and make sure it’s secure.
Step 7 — Refit the wheel and bed in the pads
Refit the wheel. Before riding, squeeze the brake lever several times to push the pistons out against the new pads. Then bed the pads in properly — find a safe stretch of road or trail and do 10–15 firm stops from moderate speed, allowing the brakes to cool between each one. This seats the pad material against the rotor and restores full braking power.
Common questions
How long do disc brake pads last? It varies significantly depending on riding conditions, pad compound, and rotor condition. In dry conditions, resin pads typically last 500–1,000 miles. In wet and muddy conditions, considerably less. Check them every few months.
Resin vs metallic pads — which should I choose? Resin pads are quieter, gentler on rotors, and perform well in most conditions — they’re the right choice for most trail and leisure riders. Metallic (sintered) pads last longer and handle heat better, making them better suited to aggressive descending or e-bikes. The B05S pads we stock are resin.
My new pads are squealing — why? Usually because the pads haven’t been bedded in properly, or because the rotor or pads have been contaminated with oil or grease. Clean the rotor with isopropyl alcohol and repeat the bedding-in process. If squealing persists, the pads may be contaminated and need replacing.
Can I fit metallic pads in a caliper designed for resin? Most Shimano calipers accept both resin and metallic pads of the same shape. Check your brake manual or the compatibility handbook to confirm.
Peak Bike Station stocks Shimano B05S resin brake pads — available in store at Hadfield or with free UK delivery on orders over £18. Not sure which pad you need? Download our free compatibility handbook.