Know which brakes you have
Most everyday bicycles use one of two families. Rim brakes press pads against the wheel rim; they are simple to inspect and adjust. Mechanical disc brakes press pads against a rotor at the hub using a cable, while hydraulic disc brakes use fluid instead of a cable. The basic cable adjustments below apply to rim and mechanical disc brakes. Hydraulic systems use a sealed fluid circuit and are usually left to a shop for bleeding.
Before you start
Brakes are a safety system. If a lever pulls all the way to the bar, a pad is worn through, or a rotor is bent, stop and have the bike inspected. The notes here describe routine fine-tuning, not repair of damaged parts.
Setting pad clearance
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Inspect the pads
Check that pad material remains above the wear line and that the surface is even. Replace pads that are close to the backing.
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Centre the pads
On rim brakes, the pads should meet the braking surface squarely without touching the tire or hanging below the rim. On disc brakes, the rotor should run between the pads without rubbing.
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Spin and listen
Lift the wheel, spin it, and confirm it turns freely. A faint rhythmic rub usually points to a slightly off-centre caliper or a small rotor wobble.
Using the barrel adjuster
The barrel adjuster is the small knurled dial where the cable enters the lever or caliper. Turning it changes cable tension without tools:
- Turn it out (counter-clockwise) to take up slack as a cable settles or a pad wears, bringing the bite point closer.
- Turn it in (clockwise) to add clearance if the pads start to drag.
- Make small quarter-turn changes and test the lever between each one.
Checking lever feel
| What you feel | What it usually means |
|---|---|
| Lever firms up roughly a third of the way to the bar | Healthy range for most setups. |
| Lever pulls almost to the bar | Cable too loose, pads worn, or air in a hydraulic line. Investigate before riding. |
| Pads drag with the lever released | Too little clearance; add a little with the barrel adjuster or re-centre the caliper. |
| Squeal when braking | Often glazed pads or a contaminated rim or rotor. Clean the surfaces; replace contaminated pads. |
Wet and winter braking
On wet rims, braking power arrives a moment later as the pads clear water from the surface, so leaving extra stopping distance is sensible. Salt and grit shorten pad life over a Canadian winter, which makes regular pad checks part of the seasonal routine rather than a once-a-year task.
When to hand it over
Hydraulic bleeding, rotor truing, and replacing seized cables are jobs where a qualified mechanic and the right tools save time and protect a safety system. There is no shame in booking those in.
Publicly available references