HOW TO STOP SQUEAKING BRAKES?
December 26, 2005
Back to questions
My wife bought a new mountain
bike and we cannot figure out how to get the back breaks
from squeaking when used. I tried break cleaner and towel
and nothing. Any suggestions?
First, I recommend a helpful book:
the dictionary. Without one I couldnt write about
this stuff, and it looks like you shouldnt either.
Next, process of elimination. Cuz
youve got a new bike I wouldnt suspect the bike
has dirty wheel rims and brake pads, but just for yucks
Id clean em firstwhich you say youve
done. If you didnt wipe off the insides of the brake
pads (slide that rag between the pad and the rim and clean
the pad like shining a shoe), do that.
Another likely cause of squeak:
Bad toeing. And I dont mean biking while barefoot.
When braking, the front part of the bikes brake pads
should contact the rim before the back part. In good lighting,
look at the brake pads from above, then squeeze the brake
lever. If it doesnt toe correctly, take the bike to
a bike shop (ideally, one at which you bought it) for correction.
Or to DIY try Park Tools pages
on brake repair (scroll down to PAD TOEING).
October 26, 2009
Thought you might like to hear
of a guaranteed way to stop this irritation. It is caused
by “stiction”—a relative of friction where
the objects slide over reach other and “stick and
release” at a very high frequency, hence the squeal.
All bike brake blocks contain rubber,
and natural use puts a thin film of rubber on the rim. Thin
films are notoriously easily oxidized; when you oxidize
rubber, the result is very sticky. (If you have ever come
across “perished” rubber you know what I mean).
In fact the thin film is almost identical in properties
to contact cement or adhesive.
Because it is oxidized, the film
dissolves only in a limited range of solvents, typically
those found in cellulose paint thinners. Simply cleaning
the rims rarely works, but I can guarantee success if you
use xylene on a paper pad, and if you can't get that, then
any cellulose thinners from your local auto accessory shop.
Thanks, Frank. Tho I wish you'd
stop sending bikers to auto stores. Anyway.
Other names for cellulose thinners: acetone, toluene, and
methylbenzene. Consistent with the fact that you'll probably
find this stuff in stores that sell automotive paint, some
consider it environmentally nasty.