Bicycle Mechanics - Sqeaky brakes

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breaking away
01-19-08, 12:03 PM
I have the avid shorty 6 contis with drop bar levers (tektros) and the front brakes squeal!! what is the best way to fix??
You can clean the rim, sand and toe in the shoes. I've wondered if spoke tension might have something to do with it as well... sympathetic vibrations of the spokes and all that.
I've tried all the 'fixes'. A disc finally did it for me.
graybeard
01-19-08, 12:57 PM
Always make sure rim is clean and no reside oil , waxes etc. Make sure pads are new enough to still be soft rubber and not dried out and hard. Generally a soft compound brake shoe is better than a cheaper hard compound. Also check to make sure the cantis do not have excess pivot wear. It is important that the shoe touch the rim with the leading (front) edge before the tail end when applying the brakes. If shoe is not toed in at the front by at least 1mm , it will usually squeal. Obviously, worn pivots on the cantis would exacerbate the problem by allowing the back of the shoe to hit rim harder than the front.
Good luck ,
breaking away
01-19-08, 01:42 PM
Whats the best way to toe in the shoe??
operator
01-19-08, 01:49 PM
Whats the best way to toe in the shoe??
With your hand.
The other trick that nobody ever does unless it's a last resort is sanding a 45 degree trailing edge to the pad. That and gently sanding the rim down with sandpaper pressed up against the rim surface with the brakes on.
There is no squeak that cannot be fixed.
onbike 1939
01-19-08, 03:02 PM
My Tektros with soft pads squealed for months and nothing I could do would stop them. Eventually I took a rough file to the pads and this did the trick.
flip18436572
01-19-08, 03:47 PM
Usually clean the rims and/or the pads. Filing the pads will sometimes fix it, and one person cut small grooves with a file across the pad to reduce the squeal.
-=(8)=-
01-19-08, 03:50 PM
How about disks ?
The front disks of my new bike sing like rubbing the rim of a wine glass
with wine on your finger.....Its driving me nuts :eek:
graybeard
01-19-08, 04:35 PM
Sqealing disc brakes are usually caused by contaminated brake pads. Try cleaning the disc rotors with rubbing alcohol and a clean cloth. remove pads and make sure they are clean also, light wire brush and alcohol work well on pads also.
Check to make sure the caliper is centered and parallel to the rotor. Road test bike for sqeeeel.
One trick that sometimes helps is to take a water bottle and apply substantial water to the caliper on the road test while braking.
If all above fails , dig out a $20 bill and buy some new pads and instal . Always use caution when installing pads and working on disc brakes.. Be careful with fingers getting into the rotor ..ouch ouch..
As mentioned contamination is the cause 90 % of the time, so dont spray lubes , cleaners, waxes on your rotors/calipers. Using the coin op car wash is bad because so often there is wax in the hose when you first turn it on. Using spray chain lubes & spray waxes is also a problem. Washing your bike in the driveway with car wash soap can be bad as many Auto soaps also have a wax in them. The best soap to wash your bicycle with is blue" Dawn "dishwashing soap. (regular dish wash soaps have oil emolients in them to make hour hands soft and pretty. Doug Dye, (Cannondale N.W. sales Rep) recommended the blue Dawn years ago, and I use it all the time. it works.
good luck
graybeard
01-19-08, 04:41 PM
I often use a shim inserted under the back of the shoe to hold it out the thickness I want. The more worn the calipers are the more toe in you need. Small piece of thin folded cardboard works well (Matchbook?) or used whatever you have handy. Get another person to squeeze the brakes on with the shim under the back of the pad , while you align and tighten. If you dont have a helper to hold on the brakes , use a big rubber band.( old inner tube cut up Etc)
How about disks ?
The front disks of my new bike sing like rubbing the rim of a wine glass
with wine on your finger.....Its driving me nuts :eek:
In that case just jam your Converse between the seat tube and the back tire. With practice you'll be able to modulate braking force easily. :)
cyccommute
01-20-08, 09:30 PM
Always make sure rim is clean and no reside oil , waxes etc. Make sure pads are new enough to still be soft rubber and not dried out and hard. Generally a soft compound brake shoe is better than a cheaper hard compound. Also check to make sure the cantis do not have excess pivot wear. It is important that the shoe touch the rim with the leading (front) edge before the tail end when applying the brakes. If shoe is not toed in at the front by at least 1mm , it will usually squeal. Obviously, worn pivots on the cantis would exacerbate the problem by allowing the back of the shoe to hit rim harder than the front.
Good luck ,
In this case it's a probably not contamination. Avids are known wide and far as squealers even with new pads that have been properly toed. I've battled with mine to the point were I ditched them for a while. I had to go back to them but this time I used Kool Stop dual compound MTB brakes.
http://www.koolstop.com/brakes/MTBPad11-00.JPG
So far the problem has been solved. Even in cold weather, the brakes haven't squealed.
graybeard
01-20-08, 09:57 PM
Don't you just love all this good advise. Next time I'm going to try those dual compound pads. Sounds like they work. Let us know how it works for you.
Thanx
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