Repair guides › Brakes
Center a side-pull caliper
The older, simpler caliper rim brake: both arms swing on one center bolt. Common on kids' bikes, cruisers, folding bikes and older road bikes. The cable pulls the two arms together around a single pivot. With only one pivot it pulls to one side easily and is weaker than a dual-pivot caliper, but it is cheap and easy to fix. Pads are usually threaded with a nut.
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Tools
- Ball-end hex key set (1.5–10 mm): Park Tool HXS-1.2 Professional L-Shaped Hex Set ($$)
- 1/4" click torque wrench (about 2–17 Nm) + bits: Pro Bike Tool 1/4 inch drive click torque wrench set (2.2–16.9 Nm) ($$)
- 12" adjustable wrench: Crescent 12 inch adjustable wrench ($)
Compare Good, Better and Best for each tool
Steps
- Loosen the nut that holds the caliper to the frame (behind the fork crown or brake bridge) a quarter turn.
- Squeeze the lever and hold it: this centers the arms on the rim. Tighten the nut while holding (8–10 Nm).
- Still rubs on one side? Many single-pivot calipers have two thin nuts on the front of the pivot: hold the rear mounting nut and turn the front pivot nut a few degrees with a thin wrench so the rubbing pad moves away from the rim. Check and repeat.
- Put a drop of light oil on the pivot and the spring ends; wipe any oil off the rim and pads.
- Set cable tension so the pads sit 2 mm from the rim.
Torque
| Fastener | Torque |
|---|---|
| Caliper mounting nut | 8–10 Nm |
Diagram
Seen from the front of the bikeFront brake
Signs it needs doing
- Keeps rubbing on one side (twists on its bolt)
- Squeal
- Spongy or weak braking
- Arms stick (dry pivot)