Howdy. i posted a couple days ago asking for tips and thoguhts on brake squeal. i was not, as i
had naievely hoped, immediately inundated with secretive tricks and age-old wisdom, so i did the
best i could with my own knowledge and the archives, and present the following for you to pick
apart. post if there are any glaring mistakes, additions, etc. when i quoted sections from posts,
i attributed with a name and email address. if it shoudl be just a name, or just an email, or
neither, let me know.
best
anthony
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Practical Steps towards quieting squealing brakes.
Toeing in brakes is the most basic and widely known advice. A few specifics regarding various types
of brakes:
V-brakes. Start with no pad toe-in. If they squeal, try toeing them in a little. Aim for no more
than 1/32". A lot of toe in is unacceptable as there is not much cable travel to spare and you get
mooshy action.
Cantis. Start with them slightly toed in. Possible starting point might be width of a dime at first
contact of front of pad. Popular wisdom seems to be quite supportive of toe angle experimentation
with cantis. If they squeal, try a steeper angle. 1-3mm is a good realm to stay in.
Road brakes. Start with no toe in. Many calipers do not have hardware (spherical washers) to toe in
pads. There are many aftermarket brake pads that toe in easily, so that is one good option if they
squeal. Unlike beefy brakes like cantis and v's, you can generally bend a road caliper to toe the
pad in. This is, of course, a cinch with flimsy department store calipers. It was common practise
with older road calipers like centerpulls, and there is even a park tool made specifically to do
this. Modern road calipers, dual pivots especially, are pretty beefy and don't take as kindly to
'metalworking'. Some new calipers come noticeably off kilter, either toed in the wrong way, or
otherwise misaligned. It is said that cold setting these new calipers is a bad thing, as anytime you
bend aluminum there is some risk of damage- present or future. However, I see mechanics in shops
bend (very small bends, mind you) modern road calipers with regularity. No problems- Yet. YMMV. An
alternative to bending calipers to achieve road caliper toe in is to take the pads off the calipers
and sand them on a belt sander, or with a block of wood and sandpaper, such that they are toed in.
Disc brakes. see bottom of article.
If appropriate toe-in doesn't work, things to try, in rough priority:
-clean rim. you might even do this before toeing in. soap and water generally work. or, you can try
an appropriate solvent. Alcohol, and acetone seem to work. Automotive brake cleaner has also been
suggested. Alcohol is much better for you than acetone, acetone is a stronger solvent. Brake cleaner
doesn't sound like something you'd want to drink either, but sometimes you have to make sacrifises.
-Make sure pads are correctly oriented. Pads where orientation matters generally have an arrow that
indicates rim revolution direction. Art Harris writes: "If you have any of the "asymetrical" pads,
make sure the longer end is towards the rear." If there is no indication of correct orientation, you
could try turning them around, or switching them left for right to see if that changes anything.
-sand rim. or scotchbrite. machined rims have a roughness to them already, but sanding can sometimes
help with these anyway. with some rims, steel wool, or a 400 grit swipe is all it takes. 125 grit is
the last resort, and your rims better be pre-machined or the fine scratches will look pretty ugly
and nobody will talk to you on the club ride. -take brake system apart and rebuild clean, lubed, and
tight. neglected points would be a little grease between pad washers which can make a difference.
-clean pads. also make sure there is no foreign matter embedded in the pads. -sand pads. or
scotchbrite. if that doesnt work, file pads. You can also try sanding areas of the pad away. Sanding
a bevel into 1/4 of the leading edge of the pad has been suggested a few times. -uneven toe in. toe
in one pad only, or one pad more than the other. -Toe-OUT. yes. toe the pads the wrong way. As
little as 1/64" all the way up to 'generous' toe-out. this decreases braking power, but if you keep
it conservative it should not be a problem with modern brake systems. -change pad, either material
or construction. a cartridge pad is stiffer than a disposable brake pad. in addition, some cheaper
pads may have inferior tolerances and not seat as firmly onto the caliper. changing material can
make a big difference. -for bossed calipers (cantis/v's) a brake booster stiffens the system.
-aftermarket adjustments to brake calipers. Shimano, for example, sells shims that adjust the play
in some of their bossed brakes. This was specifically to address squealing problems in parallel-push
calipers, IIRC. -change brake calipers. stiffer might help. or just changing something can do the
trick. higher quality does not necessarily mean less squealing, but it generally is a step in the
right direction. -you do have aluminum rims, don't you?
Misc. Tips and Tricks.
Popular wisdom on R.B.T
To sand your rims, and clean any contaminants off at the same time, you can do it while riding. From
a variety of posts, your options include riding in the rain, or through puddles, or mud, while
braking a lot. Putting an abrasive on the rims while riding such as bathtub cleaner, etc, laying on
the brakes, and rinsing it off afterwards with a waterbottle can work too.
Mellerio: [email hidden]
I have tried everything under the sun to quiet XTR v-brake squeal on my Cannondale Headshok Fatty
SL. A Shimano Carbon Brake Booster works because it dampens the vibration. This led me to find other
solutions to dampen vibration. I tried rubber bands around the pivot arms, etc. and nothing worked.
Today I tried placing a 1/8" O-Ring between the v-brake and the brake boss mount. I tightened down
the v-brake, compressing the O-Ring and took the bike for a spin (without the carbon booster). No
squeal!!! [Although in the rain they still squealed]
From Mike Jacoubowsky: [email hidden]
First, just for kicks. try reversing the front wheel.
From Gmaker: [email hidden]
-Observe the wheel from above in very good light. -Very slowly apply brakes. -Carefully check if the
wheel deflects slightly in one direction as a result of one pad applying more force than the other
*just when they hit*.
This can happen even though the pad standoff appears equal and the pads seem to move evenly. Adjust
pads to stop this.
Counter-intuitive, and unproven, From K. Becker: [email hidden]
Here's an unconventional cure for brake squeal: Put a little wax on the rims or the pads, rubbing
them lightly with a crayon or a candle works well. I've used this method on several of my neighbor's
bikes, since the metal used for brakes on cheap bikes is often too brittle to toe-in. The wax
actually seems to improve the performance, although if you used too much it might decrease it, so
apply sparingly.
From Neil, at the shop I work at
If all else fails, or you are in a hurry, brushing a little talcum power on the brake pad seems to
take squeal away. Unsure about how long it lasts.
The Kool Stop Salmon Legend: A Red Herring?
Koolstop salmon pads are highly recommended on r.b.t for their power and quality. On my own bike, I
can feel a marked difference in power when running the KS salmons. However, all is not golden. Some
or all of these salmon pads seem to be particularly resistant to de-squealing with some setups. Many
posts volunteer alterations you can make that may or may not cut down on squeal, including sanding
off the plow tip, sanding a bevel into the pads, sanding in a 'toe-in', etc. Many suggest koolstop
dual compound pads for bikes in need of quality pads but with serious squealing issues with the
full-salmons. Another possibility to reap the benefits of grippy salmon is to use the KS salmon
cartridges with a stiff metal cartridge holder.
Things that can cause a brake that wasn't squealing before to start squealing;
-coating the rim with a substance that exaggerates the stick-slip behavior of pad on rim. examples
include getting oil or grease on the rim surface, or biking through wet grasses as mentioned in the
FAQ. Fix: clean the rim. -Too clean. This is one that has happened to me. It seems that some amount
of dirt or abrasive on the rim can keeps things quiet for squeal-prone brake systems. I once cleaned
the rims on one of my squeal-prone rides with alcohol, and suddenly my brakes were squealing after
months of silence. I cleaned again. More squeal. I figured it was impure solvent, so i upgraded to
acetone, and cleaned them with that. still squealing like a pig. I had to lightly sand the rims and
toe them in more to shut them up. -pads wearing down and developing new resonant properties. re-toe
in, sand, or whatever it takes. -bad karma. call your mother, clean your bike, feed your dog, and
hope for the best.
Disc brake squeal:
Y'know how all the manufacturers say not to get oil on your rotors/pads while setting up/bleeding
your brakes? Well. Now you know. Clean them. Clean the pads. Clean everything. Some companies say
that cleaning pads of oil is useless and hint that they might need replacement. YMMV. Below find
some tips. In addition to these, check that everything is clean, lubed, and tight. As a last resort,
you could try sanding the rotor itself.
From Tony Raven:
1. Clean the disc with [solvents such as] methylated spirits and make sure it does not get oil or
wax on it - washing the bike with wax containing car shampoo can cause the problem as can clumsy
spray lubrication.
2. After cleaning the disc, take the pads out, place fine emery on a flat (glass?) surface and
rub the pad surface on the emery in a figure of eight motion to remove any glazing that may
have formed.
3. Put the pads back (in the same place as they came from, don't mix them up) with a smear of
copper grease between the pad and the piston.
4. Chamfer the leading edge of the pads
5. Ride in wet abrasive mud
From Rich Wood: [email hidden]
lightly coat the back of the pads with copper grease. You might need to put a strip of aluminium
tape on there first to stop the grease contaminating the pads.
Thank you to:
Everyone. I couldn't possibly cite everyone who's posts contributed to this accumulated knowledge,
so a big thank you and an electronic hug will have to do.