Pad Alignment

This is a very simple adjustment — so simple that one marvels at the numerous true stories of riders who, through neglect, drive their brake pads into their tire walls until blowouts result. Thankfully, most people simply limp along with only a portion of their pads striking the rim, reducing brake power and ruining the pad in a short time.

To avoid these problems, simply squeeze your brake lever, secure it with a bungee or strong rubber band, and inspect your brakes. With cantilever brakes, the pads should strike the rim evenly top to bottom (that is, both the top and bottom portions of the pad should strike the rim metal at exactly the same time), but at the upper portion of the rim. This is because the direction of cantilever brake arms causes the pads to dive down while traveling wheelward.

An Allen-wrench adjustment of the pad-anchoring bolt (which allows the pad to be pushed closer to the rim) will let you tilt the shoe face up or down so that it strikes the rim correctly.

Toe-In

Do your brakes squeal? Even after you've buffed clean your rims with emery cloth and lightly sandpapered your pad faces or replaced the pads if they're too hard? If so, it's time to learn about toe-in. That is, making the necessary adjustment to cause the forward tip of the pad (forward as in toward the front of the bike) to strike the rim before the rest of the pad engages it. The idea is that this reduces or eliminates the vibration that can occur when the entire pad strikes the rim simultaneously. Ending the vibration kills the noise.

Side-pull brake in released position;
note the brake cable adjusting barrel
and set wheel

Those of us with side-pull brakes on our thin-tire bikes must first remove the pads and then, scarily, bend both brake arms (at the same time, using wrenches on the flat parts of the arms) slightly. Bend them in the direction that you wish the pads to strike, forward tip first. Then reattach the pads and see if the arms need more bending in one direction or the other. Be careful. Reef on these arms and you're in the market for new brakes.

If you have direct-pull brakes, you won't be attempting toe-in at all and instead will have to resort to installing a small"brake booster" device that ends the vibration and thus the noise. This installation isn't difficult, but take your time to do it right. Do a quick Saturday-morning pre-ride rush job so you can meet your friends at the trailhead and you're liable to steal far more of their time when you eat a tree.

The rest of us should look for the beveled "angle" washers (also called "shaped spacers" or "shaped spacing washers") at the pad-mounting bolt and nut, which can be rotated by hand once the nut is loosened. Begin by wiping everything clean and reminding yourself that you should be looking for relatively minute changes of angle. Don't expect to get things right the first time around.

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