I have never had such a persistently squeaky set of brakes. The pads are new kool stops on a cheap specialized hybrid that I am repairing for a friend. The pads are properly aligned. I have toed them in(front first) cleaned the rims with solvent and sanded the pads, but they still squeak. Its not loud, but with medium/hard pressure they squeal. Any tricks???

Nothing works 100% of the time. It sounds to me like you've already done all of the common fixes. If you are working with ProMax or Tektro brake arches, a $20.00 set of Shimano Alivios might do wonders. I hate cheap brakes.

The Kool Stop black compound is less likely to squeal than the salmon compound, if that's a factor. You may need to toe them WAY in, if the brake arms have some play. I had a similar problem with Avid Shorty 4 brakes, just too much play and it couldn't be adjusted out. With black Kool Stop pads toed way way in, the squealing finally was gone and the braking was good.

Be sure there is absolutely no play in the brake pivot(s). Sand the braking surface of the rim with 80-100 sandpaper.

The funny thing is, the tektros are about equivalent to ultegra level Shimanos (the tektro dual pivot roads that is). They are good value for the money. Stop knocking things just bcause they aren't "brand name".

I'm going to have to suggest that you pickup a cheapo set of pads anywhere and see if that fixes it. It may be the kool stop, however unlikely that may seem. The other cause could be loose bolts holding the pad, or the entire brake assembly itself. Have you also checked the rim for trueness?

Could also be a problem with the rim. There may be no way to get rid of the squeal short of replacing the rim.

Well, I doubt those "Ultegra level dual pivot Tektros" are what he has on this hybred. I've worked on enough lower end hybred and comfort bikes to stand by my statement. I'm not knocking them because they're not brand name, I'm knocking them because they suck.

I had the same problem with the black compound pads and Shimano STX brakes when I replaced the original 12 year old pads. I finally toed them WAY WAY in. The squealing stopped and the braking is good.

I've got a squeeky brake that has to be in the rim. I've replaced the pads, then original brakes, and then the pads on the second set of brakes. It still squeeks. I finally gave up with trying different adjustments and just ride with the squeek. One of these days I'll have a new wheel made as that's the only thing left to try.

This depends on the nature of the squeal. Some combination of the brake arms, fork legs, brake cable, pads, headset, etc. are resonating at a specific frequency. You either need to increase the damping with stiffer components or shift one or more of the offending natural frequencies to where it not longer causes a problem. I got rid of the squeal on my Soma Double Cross by doing several things:

I tightened down the headset to the point where there was absolutely, positively no play at all. It is probably a little too tight but if I wear it out I can install a Chris King. This eliminates some feedback from the fork flex/movement pulling on the brake cable. Less feedback = more damping.

I replaced the link wire with the next longer version. I think I went from a Shimano "F" to a no-name "B" that was in the LBS's junk box. This reduced the leverage that can be applied to the brakes with through the levers and the fork flex/movement. Less leverage also means less feedback.

These two tricks got rid of about 30% of the squeal for a grand total of $1.

I then found the right set of brake shoes. Salmon Kool Stops did the trick for me. Their black ones were actually a step back from the Shimano pads. The severe conditions pads are a bit harder and tend to raise the resonant frequency of the brake arms/pads. I also toed them in about a "penny's worth" more than the Kool Stop instructions recommend.

I used to have a love/hate relationship with the Canti's on my cross bike. Now I love them when I'm out riding with the roadies. I can brake so much later and aggressively that it's a lot of fun when we're riding through twisty stuff with bits of gravel and potholes.

There are numerous other fixes as well: cleaning the rims with fine steel wool or scotch-brite, moving non-threaded shoes further in or out, putting spacers behind threaded shoes, wider rims, stiffer forks, stiffer brake arms, compressionless cable housing, etc. Keep experimenting and paying attention to the frequency as well as the volume. Lower frequencies require more driving force to oscillate. Higher ones are more easily damped.

One more thing. Good luck. This problem often requires A LOT of patience.

I'll second cachehiker on the resonance. The squeal on my fiancé's bike was coming from the seat tube/seat post. No amount of tightening and tuning would get rid of it. I finally stuck a tightly-wadded piece of fabric into the tube to change the resonating characteristics. No squeal since.

Did you try toeing in the black Kool Stops that much? That additional toe-in may be the main reason why the salmon ones worked better for you. I spoke directly to the technical information department at Kool Stop, and they are the ones who confirmed that the black compound is less likely to squeal than the salmon.

I'm guessing a bit here because I can't take the data acquision system and strain gauges I use here at work out the road. The power cord is too short, I can't find anybody who can run fast enough to push it, and I'm afraid of getting rear ended when I apply the brakes while towing it.

First off, this is the only time I've ever had a brake squeal problem I couldn't fix with a basic toe-in adjustment. Black Kool Stops were the first thing I tried and they made the problem a little worse. I toed them in a bit more and it helped but it wasn't a solution so I put the old Shimano pads back on and started looking elsewhere. Too much toe-in is only a temporary fix anyway. As soon as the nose of your pads wears down enough, the squeal will come back.

I think the natural frequency of the fork cable interaction was close enough to the brake boss lever shoe interaction that the oscillations were driving each other. Having the fork crown clamped really hard in the headset and lengthening the link wire damped and lowered the first resonant frequency. At that point, the black pads moved the two frequencies closer together and the salmon pads moved them further apart. It's a cross bike that sees a lot of commuting and limited touring duty anyway so severe conditions pads aren't a bad idea.

Given no alternative to consider, this is the only explanation I've come up with that makes sense to me. I suspect serious brake squeal issues often have more than one cause. It's easy go after the primary one, the brake shoes and their position, and ignore the others because it usually works. You increase the damping and/or shift the natural frequency of the first cause and there is nothing left driving the second cause hard enough and at the right frequency.

Absolutely true. It's definitely important to look at the whole system, including rim material. That's another factor (besides the irremediable play in the brake arms) that caused so much trouble for me. I'm just happy to have good, quiet brakes now.

I cleaned my rear rim with brake cleaner and to my dismay during my next ride they squealed horribly. But to my delight they stopped after some use. Maybe the rims are too clean causing the pads to grab at a frequency high enough that it's audible?

I've had that happen too. It's usually pretty temporary, if it's just that they're "squeaky clean".

exteme toe in worked for my squeel toed them in so much that my front wheel that is out of true hits one of the pads

Time to true your front wheel!

I had a persistent brake squeal that was fixed when I finally found a little bit of play in my wheel bearings and fixed that.

Learn to love it.

I only say this because I've had to dial my Koolstop'd 990s on my BMX to ZERO toe in for optimal performance during wheel locked tire planting maneuvers.
This of course means my bike sounds like a city bus when stopping.
It really gets pedestrian's attention.

Thanks for all the advice... I am going to check the bearings for any play. I am thinking it may be the rims, because theres a not so smooth joint, should I try sanding(err grinding, its thick) down the joint. I can't say if the original brakes squeaked because the pad was ripped in half when I ended up with the project.

Recently replaced the pads on my front brakes to try and eliminate a VERY loud shriek. I've tried every possible configuration of toe, height on the rim, distance to rim, and I've cleaned the rim with 240 sandpaper, but to no avail. However, I noticed a weird effect - the brake does NOT scream when the front wheel turns in REVERSE. This makes me think the problem lies outside the pad/rim interface: could it be play in the attachments from the calipers to the fork, for example? I've shot some WD40 in there, but still nothing.

Many thanks for all replies - I can provide some pics if they would help.

M.

Toe-in is always looking forwards in the direction of travel. If you're looking at the front brake by standing in front of the bike, the pad-edge that must be closer is at the REAR (furthest from the fork). It would look like TOE-OUT if you're facing backwards towards the bike.


What kind of brakes? Caliper or cantilever? As already mentioned many times, play in the brake-arms is the main cause of the problem. Toe-ing in the pads only deals with the effect (squeal) of the problem, but don't actually do anything to fix it. When the pads wear parallel to the rims, the squeal will start yet again.

I've found that removing as much play as possible but not binding the brake-arms to be the longest-term solution (actually improves braking-feel, modulation and power as well by allowing you to use most of the brake-pad, rather than just the tip).

For single-pivot caliper-brakes, there's usually is an adjustment-nut and locknut at the end of the pivot-bolt. Disassemble the brake and grease the mating surfaces on the arms and washers. Re-assemble and adjust the adjustment-nut so that the arms bind just slightly. Then use two wrenches to loosen the adjustment-nut up into the locknut that you're tightening down. This relaxes the adjustment slightly and frees up the slight binding on the caliper to give smooth action with no play.

On dual-pivots, there is typically a stack of thin washers under the mounting bolt for each arm. You can remove a thin washer at a time until there's no play.

For cantilevers, the pivot-post for the brake-arm can be filed shorter so that the brake isn't sliding up and down the post. Depending upon the brake, this post can be the one on the bike itself (early models), or is the sleeve that slides over the mounting post on later models.

Once you remove as much play as possible, you'll find that slight toe-in is all you need.

Sometimes toe out helps. Give it a try. bk

I had to take some black kool stops off one bike, a Peugeot with Mafac racer centerpulls. It was ridiculous. I mean really embarrassingly loud! I tried all the usual stuff.