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Technically Inept Newbie Question: Squeaky Brakes(7 posts)

Technically Inept Newbie Question: Squeaky Brakessockey19
Jul 14, 2003 11:15 AM
My rear brake is horribly squeaky, how can I fix it?
submit an insurance claim.Steve_0
Jul 14, 2003 11:20 AM
seriously, try canting the pads a tad.
I'll interpret in newbeeseKristin
Jul 14, 2003 11:36 AM
That means use some fine grain sand paper to rub down the contact area of the brake pads. They can get glazed--just like car brakes--and become squeeky. Sometimes after I've ridden in the rain, I'll do this.
squeaky pads or squeaky caliper?jw25
Jul 14, 2003 11:33 AM
Do you mean it squeaks when you actuate it, or the pads squeal when you're riding?
For a squeakiy caliper, I've found the culprit is one of two places. The thin washers/bushings between the arms at the mounting bolt can dry out, but a drop or two of oil there will do wonders. The spring arm contact points behind the caliper can also squeak, though most brakes have plastic bits there to prevent metal to metal contact. They do break, though, and aren't really necessary. If one's come off, a drop of oil there will do the trick. You'll need to reapply at regular intervals, though.
If it's the pads hitting the rim while you're rolling, you may need to reposition the pads, or deglaze them if they're old.
Actuate the brake, and see how the pads contact the rim. If the rear of the pad(towards the rear of the bike) hits first, that's probably it. Modern pads have washers that let you set the toe-in. Set the pads so they hit flat or slightly front-first.
If that's not it, the pads may be glazed. The easy fix is new pads, but you can also scrub off the glaze with some fine-grit sandpaper, which should revive them. Lower-level Shimano pads (and even Ultegra of a few years ago) are notorious for glazing, and are best replaced. I prefer Kool-Stops, personally, but your LBS will undoubtedly have an opinion as well.
Stick your big toe in ...Humma Hah
Jul 14, 2003 11:55 AM
... er, sorry, I mean you need to "toe-in" the brakes. This operation is easier on older brakes due to their wimpier construction, but I've been assured it still works on modern brakes.

Basically, if you look at how the wheel turns, if the leading edge of the pad, relative to rotation (i.e. the end of the pad closest to the back of the bike), contacts the rim first, it will tend to grab, leading to a squeal. You want the TRAILING edge to hit first, ever so slightly.

This is accomplished by gentle bending, generally with an adjustable wrench.
BENDING???off roadie
Jul 14, 2003 12:41 PM
I haven't ever had to adjust my road bike brakes, but my MTB brakes don;t need no stinking bending. The pads bolts run through a stack of washers that are curved on thier faces such that the bolt can be angled relative to the rim, no bending required.

Maybe this is nescessary in MTB's because of the wide range of rim widths used. On a road bike, most rims are close to the same width, so one toe-in setting will work for most rims, preventing the need for multiple "adjustments" via bebding. Still, it seems like a rather obvious design shortfall to me.
Pad toe-in may not require bendingKerry Irons
Jul 14, 2003 4:37 PM
Look carefully at the brake pad system. There may be the ability to toe-in the pads by loosening the attachment bolts and shifting the pad - it depends on the design of the brake. The toe-in should be slight - the back of the pad should be set to double the thickness of a business card. Even if you have to bend things, the bending is so slight that there is no compromise of your brake strength.