All Maintenance Tasks · Monthly
Check Brake Pads
Brake pads are the only part of the bike you deliberately wear out, and they give you a long, quiet warning before they run out. Miss the warning and the pad backing meets the rim or rotor, which turns a fifteen-dollar consumable into a wheel or a rotor. Worse, worn pads pull the lever further toward the bar, so the moment you need the brake most is the moment it feels wrong.
Interval
Monthly
Once a month, or after roughly 200 miles
Time on the job
10 minutes
Once you have done it a few times.
You or a shop
Some practice
The stop signs further down are the real answer.
Applies toRoadMTBHybridE-bikeKids
How often, really
Once a month is right for dry-weather commuting. Wet roads carry grit that grinds pads down several times faster, so a rainy month is worth checking twice. Long descents, heavy loads, a trailer or a child seat all shorten the interval. If you ride somewhere flat and dry and only go out on weekends, every other month is honest enough.
The interval on this page is Monthly. Once a month, or after roughly 200 miles.
What you need
- A bright flashlight or a phone light
- A hex key set for the caliper and pad bolts
- A clean rag
- Isopropyl alcohol for rotors, never on the pad face
Doing the job
Look at the pad, not the lever
Lever feel drifts so slowly you stop noticing it. Get your eyes on the pad itself. On rim brakes, squeeze the lever gently so the pad meets the rim and look at the pad from the side. On disc brakes, look down into the caliper from above with a light, or pull the wheel to see the pad clearly.
Find the wear indicator
Rim pads have grooves cut into the braking surface. When the grooves have disappeared, the pad is done. Disc pads are measured as friction material plus the metal backing plate; most manufacturers state a minimum total thickness in their own documentation, and it is usually described in terms of the friction material being nearly gone. Use the figure from the pad or brake manufacturer, not a number from a forum.
Check that the pad is wearing evenly
A rim pad worn into a wedge, thin at the top, means the pad is riding too high and will eventually touch the tire. A disc pad worn on one side only usually means the caliper is not centered or a piston is sticking. Both are telling you something is out of alignment, and replacing the pad without fixing that just wears the next pad the same way.
Feel for glazing and pick out what is embedded
A glazed pad is shiny and hard, and it squeals and grabs instead of biting progressively. Rim pads collect metal slivers and grit that score the rim; pick those out with a sharp point and wipe the pad. If a disc pad is glazed or has soaked up oil, it is not something to clean and hope for. Replace contaminated disc pads.
Check the surface the pad works against
On rim brakes, run a fingernail across the braking track. A visible dish, a ridge at the edge, or a wear indicator groove that has vanished means the rim is worn out, and a worn rim wall can fail under pressure. On disc brakes, check the rotor for deep scoring and for the minimum thickness the rotor manufacturer stamps on it or publishes.
Test at walking pace before you commit
After any brake work, roll the bike at walking pace on a quiet, flat surface and pull each lever separately. The bike should stop straight, without the lever reaching the bar and without a grinding noise. Do this before you ride in traffic, not after.
Stop and take it to a shop
If any of this shows up while you work on check brake pads, put the bike down and let a mechanic look at it. None of these are things to ride out and see how it goes.
- The lever pulls all the way to the handlebar, or it feels spongy and gets softer the longer you hold it. On a hydraulic brake this points at air or fluid loss in a sealed system, and bleeding a brake is shop work.
- You can see fluid, a wet film or a dark stain anywhere on the caliper, the hose, the lever body or the rotor. Stop riding the bike and have the brake looked at.
- The rim has a hollow you can feel with a fingernail, a visible crack, or a wear indicator that has worn away. A rim wall that thin can split, and that is a wheel replacement, not a pad replacement.
- The pad is worn down to the metal backing, the rotor is scored deeply enough to catch a fingernail, or the pad wears out again within a few rides of being replaced.
- Anything about the brake is unfamiliar to you and the answer is not obvious after ten minutes. Brakes are the one system on the bike where guessing has no upside.
Where this usually goes wrong
- Judging pads by how the brake feels at the lever. A worn pad and a correctly adjusted brake can feel identical for a while, right up until they do not.
- Cleaning an oil-contaminated disc pad with degreaser and putting it back. The contamination has soaked into the friction material, and it comes back warm.
- Replacing pads without checking why the old ones wore unevenly, which quietly puts the new pads on the same path.