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Replacing the Brake Pads
Standard threaded-stem V-brakes
Cartridge system
pads Disk
brakes
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Be sure you have the correct replacement brake pad! El Cheapo bikes may
have different pad systems than those shown here. Common brake
pads: cartridge system (top), side-grip (left), and threaded stem pads (right)
with ball-joint spacers for V-brakes. |
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Release the brake cable by removing the cable drum (cantilever brakes) or
popping the retaining clip off the cable housing (V-brakes) Releasing
the brake cable. |
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Remove the old brake pad. Before doing so, note the
position of the stem on the slot in the brake caliper. Also note where the slot falls
among the ball-joint spacers on the stem of the brake. (One set of spacers is larger than
the other. As the brake wore down, the spacers may have been exchanged.) If there's any
tread or grooves left on the pad, note which way it points.
Cable released. |
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The brake pad is removed by turning the nut on the end of the threaded
stem. Put the new pad in its place, being sure to note whether the pad has a specified
direction for mounting. In general, if there are Vs in the pad, the V points toward the
back of the bike -- the direction the wheel will be turning into it. Use the wider
ball-joint spacer on the pad side of the caliper if you want your calipers wider apart. If
you like them close, put the wider spacers on the nut side of the caliper.
Installing a threaded-stem brake pad. See below for cartridge-system brake pad. |
| A solid-stem brake pad has a pusharm that is gripped from
the side. The nut on the opposite side of the cantilever loosens or
tightens the grip on the pusharm.
Use a wrench to loosen the nut. Once
the pusharm is loose, turn it upward. Pull the brake pad and pusharm out
of the mechanism. |
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Dial the cable-length
adjuster on the brake lever almost all the way back (leave about 1/8 inch). Reattach the retaining clip to the brake cable. If the cable
was tightened to compensate for worn brake pads, you may need to let the cable out a
half-inch or so at the attaching screw on the caliper. Drawing
in slack from the cable. |
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Fine-tune the position of the pads. Each pad should be only about
1/8" from the rim, with the stem pointing perpendicular to the facing edge of the
rim. Partially tighten. Now toe the brake pad.
This means the FRONT end of the brake pad will be a trace closer to the rim than the back
end. Put a couple of business cards under the back end of the pad, then grip
the brake lever to tighten the pad down against the rim. Now tighten the stem fully.
Do this for each side. Checking the clearance and alignment of the pad on the rim. |
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If one caliper rebounds further away from the rim than another, or if one
pad is rubbing the rim, adjust the spring tension on the calipers. Turn only 1/4 turn at a
time, gripping the brake lever after each adjustment, then spinning the wheel to check
alignment of the pads. You need to increase the spring tension on a pad that rubs (by
turning the screw IN), so it rebounds further away from the rim. If the distance between
rim and pad varies significantly as the tire rotates, you need to true
the rim. Adjusting the tension for symetrical brake
motion. |
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If necessary, make a final adjustment of the cable length using the
adjuster at the brake lever. This determines the amount of "pull" you make on
the brake lever before the brakes engage. Leave about one and a half inches of daylight
between the brake lever and the handlebar when you're gripping the brake lever hard. (Some
riders like the brake action closer to the handlebar. If so, you can back the cable
tension off, but be certain there's at least 1/2" space between lever and handle bar
when the brake is gripped as hard as possible.) For further information on brake tuneups, see that section. Adjusting
the cable length. |
Cartridge System Pad Replacement
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Follow the instructions above for release of the brake cable. Locate the
retaining pin at the top of the brake cartridge. Grasp it firmly with needle-nose pliers,
then pull it gently out. DON'T break it or lose it. Pulling
the retaining pin. Be careful not to lose or damage the pin! |
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Slide the brake pad out at the open end. Use a small wire to clean dirt
out of the front end of the cartridge. Now slide the new brake pad in. Push a bit, so the
hole in the pad matches the hole in the cartridge. Re-insert the retaining pin, making
certain it seats correctly. Follow the procedure above for adjustment of the brake
clearance, toeing, and tension after pad replacement. Sliding the brake
pad out of the cartridge. |
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