If you own a quality mountain bike or performance bike there is a good chance it has a cantilever style braking system. While it appears more complicated than classic brakes at the outset, it is actually the very same idea designed a bit differently. In fact, adjustment is actually easier than it is on older style brakes because you aren’t fighting the wheel itself while trying to tighten the cable set screw.
Loosen the brake cable set screw and allow the brakes to relax. The set screw can be seen in the caption outlined in a double red circle, and the direction to loosen it is indicated by the green arrows. Once loose, the cable will slide through and the brake shoes will travel away from the rim.
Grab the brakes and pull them toward each other, as indicated by the red arrows in the photograph. Pull the cable AWAY from the bicycle at the same time, as indicated by the blue direction arrows around the needle-nose pliers. Adjust it so that the brake pads are as close to the rim as possible without actually touching it.
Keep the tension on the brake cable with the pliers once the brakes are where you want them, and tighten the cable set screw, once again outlined in red and accompanied by direction arrows. Do not over tighten, but make the cable very snug in the set screw to prevent slippage, resulting in the complete loss of stopping power.
Test the braking system. There should not be more than an inch of throw at the brake handle. If there is or if you can squeeze the handle hard enough so that it contacts the handgrip, follow the steps above to re-adjust the brake shoes so that they are closer to the rim.