Thorn Cycles Forum
Technical => Wheels, Tyres and Brakes => Topic started by: Matt2matt2002 on October 03, 2018, 05:15:16 pm
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A set up a new pair of blue Swiss tops on my Case rims but had a terrible squeal start.
Toed them in. No luck
Swapped front to back
. No luck.
Narrowed the squeal down to one side on the front.
Removed pad and holder and discovered a wobble on the threaded part that enters at right angle to the holder.
The other 3 holders don't have a wobble.
Decided the wobble was the cause and called SJS.
Nice young man suggested part 30195 which although not specifically for XTR, should fit.
Reduced to £11 from £23!
Comes with pads but I should be able to swap them over.
I'll let you know if the squeal disappears.
Anyone else had this problem?
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when i used to ride with the group i loved it when my brakes squealed used to craic up the glory riders ;D ;D ;D
long live squealing brakes.
anto.
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Och, but you're a terrible man, Anto ;)
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Squealing brakes are useful to warn pedestrians on shared paths, IMO works better than a bell.
But the noise annoys my wife when I ride with her, so I generally try and eliminate or at least reduce squeal.
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I like my brakes to be silent along with the rest of the bike. However, the squeal ghoul does seem to make random appearances. I've never had a problem with swisstop blues and CSS rims. Just this week my front wheel which is now non-CSS grizzly with standard (Aztec???) blocks started practising for Halloween with no warning and having been fine for months. Then equally suddenly it has stopped, no idea why!
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Any thoughts on the causes if a squeal?
Grit? Grime?
With me it was/ is definitely one-sided.
Hopefully a new pad holder will solve the issue.
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Any thoughts on the causes if a squeal?
Grit? Grime?
With me it was/ is definitely one-sided.
Hopefully a new pad holder will solve the issue.
No clear idea. the rim looks clean but I guess some grime is involved. It's certainly possible that alignment including toe-in, unequal horizontal pull and being not parallel to rim as well as being solidly bolted could contribute. Some blocks compounds might also be to blame, especially if they are prone to picking up debris like Shimano ones.
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I'm guessing that a squeal is caused by air vibration.
If parts ( pad and rim ) are not seated square then the slight movement will result in squeal.
Any squeal experts here?
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Grit? Grime?
...and Gremlins.
Making a virtue out of necessity, and following Martin's experience, I've found that the occasional rasping squeal does give a very clear warning to pedestrians. (I've never heard anyone say, as I have on occasion with my Raven's bell with its lingering temple-bell chime, "What a nice bell!")
I use Kool-stop salmon, and occasionally dual-compound pads. Sometimes, they squeal a bit after cleaning and readjustment, but that lasts only for one or two applications, and occurs only on hard braking, e.g. for downhill hairpins.
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Och, but you're a terrible man, Anto ;)
and that's the truth John ;D ;D
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Good news and maybe not so good news.
I placed an order for replacement pad holders.
I had identified the squeal as coming from the front near side brake pad. The holder was not firmly attached to the part that holds the washers and nut. It wobbled. The other 3 holders didn't wobble.
So that must be the cause. Right?
The order arrived within 3 days. As well as the brake shoe set ( Shimano M70R2 ) I ordered a Profile Design bottle holder to match the 2 I already have, 3 spare drain plugs ( I'd dropped one the last time I did an oil change ) , ,3 SKA mudguard draw bolts, Schwalbe inner tube and and oil change kit. All well packaged.
However, upon examination both brake shoe sets wobble in the same way as the ' faulty' one that I think causes the squeal!
I've yet to swap the brake shoe but not optimistic about it curing the problem.
Any thoughts folks?
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...
I placed an order for replacement pad holders.
...
The order arrived within 3 days. As well as the brake shoe set ( Shimano M70R2 ) I ordered a Profile Design bottle holder to match the 2 I already have, 3 spare drain plugs ( I'd dropped one the last time I did an oil change ) , ,3 SKA mudguard draw bolts, Schwalbe inner tube and and oil change kit. All well packaged.
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Any thoughts folks?
I am sure that changing a Rohloff drain screw will solve your brake squeal problems.
Just joking, I could not resist.
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When I did my Pacific Coast tour, I recall telling my touring partner that he should get a bell for his bike - and I told him that a bell would have a much more pleasant sound than the brake squeal that he was using to warn others of his approach.
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............................and nobody has mentioned that universal cure all WD40 !
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Further research...
The new brake pad holders wobble in the same manner as the ones I am using so I didn't bother to swap pads to see if that solved the mystery
I swapped front and rear brake shoes and pads.
The squeal was still at the front!
So my conclusion is that it's a rim problem.
I cleaned the CSS rim with white spirit, let it dry, cleaned again with dry tissues, but still the squeal.
My rims came with the bike second hand.
Age of bike from Rohloff hub dating ( I know it's not accurate but.....)
is 10 years.
Any thoughts on how to proceed?
The novelty of waking up half the street when I return home from a late shift had worn off.
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Vary the amount of toe in, either less or more.
Some bikes I have had with brake squeal, often it has eventually gotten quieter, so each time you try something, ride for several days or a week before trying something else.
If that does not work, try cleaning the wheel with soap and water. And take the wheel out so you can clean the pads with soap and water with a brush. I am in USA, a soap that is particularly good at cleaning off petroleum residue is Dawn dish soap, I do not know if that is sold where you are or not.
If the above does not work, try lightly sanding down the surface of the pads. But those pads are expensive, do not wear too much off of them. If there is any coating of something on the pads that is contaminating the pad surface, this could reduce that contamination or eliminate it. I only mention this because on some of my non-CSS bikes, when I have a lot of Aluminum Oxide built up on my pads, I often sand most of that Aluminum oxide off of them to get back down to the rubber. Thus I regularly sand down rim brake pads.
If nothing else seems to work, squeal is a high frequency oscillation, can you figure out exactly what is vibrating? If you reach down to the brake area while riding, be very careful you do not get your fingers caught in anything.
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Thanks Mick.
Do you think that the facf I have swapped the pads front and rear and the squeal is still coming from the front, indicates the rim is the cause?
No squeal ever on the back.
I've toed in the pads to various degrees ( & no degree! ) but no change. Always a squeal on the front.
White spirit to clean the rims.
Pads are brand new.
Rough them up a bit? Well I guess I could but I can't get away from the ' front only' ever squeals. So doubt it's a pad issue.
How long should these CSS rima last? I've no idea how old they are.
Should they feel rough or dead smooth?
Thanks for you thoughts
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I already saw they were new pads and the white spirits. I do not know what white spirits is, but i suspected that is the same as Coleman stove liquid fuel.
I can't imagine that a CSS rim would be the fault.
Usually rim brake rims wear out when they get too thin to hold pressure. Has not happened to me but one of my neighbors said that a few years ago when he was braking and slowing, it felt odd, like part of his wheel was fatter than part of it, he could feel it in the brake lever. And very soon after that the rim blew apart.
But CSS rims have a surface that does not wear down to that extent.
I used to have some cantilever brakes on my Nomad rear, could not get rid of the squeal, eventually switched to V brakes and the squeal went away. In your situation where the squeal started after switching to new pads, that suggests to me that the fault is somewhere in the new pads or as you noted the pad holder.
I have no ideas other than what I already mentioned. Although I saw before that you tried a solvent, I still would try the soap and water if nothing else seems to work. Since any lubricant contaminating a brake can cause squeal, that is why I suggested the soap.
Since nobody else is throwing out other new ideas, looks like the crowd has run dry on ideas on what else to try.
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Thanks Mick
Yes, I guess it's going to be a mystery I'll have to live with. A bit like ' life '!
Toe ing in cured past problems but no luck with this one.
Strange that swapping the pads front to back doesn't cure the issue.
I wish I knew the age of the rims but having bought the bike second hand....
Once again, thank you for your thoughts.
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How about borrowing a front wheel or putting the wheel into another bike. Failing that don't use the front brake🤔
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I don't think the age of the rim will be a factor. It is true that the CSS surface does rub away and there is a school of thought that a shift to softer blocks might help braking, but I don't see how it would result in a noise. Is the braking still smooth? Is there any sign of rim damage or have the sides flared at all? Borrowing a front wheel would be an interesting experiment. Potentially easier would be to experiment with brand new cheap blocks first.
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experiment with brand new cheap blocks first
Or, you might try Kool Stop pads, which is what I use. These are not quite as expensive as the Swisstop pads. SJSC's offerings are here: https://www.sjscycles.co.uk/search/?term=Kool%20Stop%20brake%20pads (https://www.sjscycles.co.uk/search/?term=Kool%20Stop%20brake%20pads)
I've had no squealing problems with Koolstops on my Raven's (Shimano) V-brakes. (Rims are alloy, with machined faces.) Had some squealing with my derailleur bike recently, with KoolStop pads in Avid canti's, but the squeal disappeared when I eased off the cable tension. That modulated the pressure.
I realize that this suggestion is a recommendation to swap parts, not really a product of analysis, Matt, but it might work.
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I think this is what John was suggesting.
https://www.sjscycles.co.uk/brake-blocks/kool-stop-r16-v2-v-brake-inserts-ryde-rigida-css/
I use these because the Swiss pads were not in stock at SJS when I bought my CSS rims. But I have had an occasional squeal out of these pads. I have never tried the Swiss pads, so I can't offer a comparison.
But these look different than mine, it appears that they make a change to the part of the pad that presses on the rim.
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Out with 2018 and in without a squeal!!
Yeeha!
No more squealing.
It had become a real pain and no fun.
Ok - it can be a good warning in lieu of a bell or horn - but seriously - it was BAD.
I had swapped the front and rear pads ( no squeal from the rear - ever ) but it was always on the front. Probably more nearside.
I had toed in. I had toed out. Flat as well - but no luck.
I'm using CSS rims. How old? No idea but the bike is 10+ years old. It's second hand to me - and came in good condition - but no idea about age of parts.
I put on new Blue Swisstops and after a few months the squeal began.
The bike had been knocked over while parked and one theory was that the fork 'stork' that the brake assembly (XTR) slips onto, had been bent.
( What's the proper name for the stork? )
Another theory ( mine ) was that the shoe sleeve'groove that holds the brake pad was wobbly.
The T shape was not rigid. It flopped about a bit. Perhaps this caused the squeal?
But no - the new replacement ones I purchased from SJS were the same.
I had wanted to slip the blue Swisstop pads into the replacement shoe sets.
I didn't bother when I saw they were 'floppy'.
However, in desperation at the horrendous noise - today I fitted the Shimano Brake Shoe Set - M70R2
And squeal has gone.
Thoughts and opinions folks.....
The rim feels smooth. Is there any way of telling if it's times up? Should it feel rough?
The rear has a different feel. Not so smooth.
Any problems likely to arise from running none Swisstop type pads on a CSS ( worn ) rim?
Whatever 2019 brings - it will be a quiet blessing.
Happy New Year to you all.
From a very peaceful Matt
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If the CSS rim feels smooth, I do not think you can wear them out from brake wear so it probably only means that it will not work as well when wet..
Since it is smooth, just keep using your Shimano pads but occasionally look at the pads to make sure they are not wearing fast and look to see if any of the pad material is sticking to the rim.
But I would not recommend a non CSS pad on a rougher rim since a rougher rim would be like using sandpaper on regular pads.
I was curious what would happen with regular pads when I first tried my brand new CSS rims. I went a couple of km with regular pads and found that I was building up a residue of pad material on the rim. So, I immediately installed the Koolstop CSS pads. (When I ordered my frame and rims, SJS was out of stock on Swisstop pads, thus I ordered the Koolstop pads.)
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Many thanks for previous replies and advice.
The squeal persisted and I have only managed to find the solution.
It is a CSS rim with ordinary pads.
The noise was stopped by placing the pads to grip on the very edge of the rim nearest the tire.
It appears that the CSS coating has worn away at the normal part of the rim.
Fingers crossed this is the solution.
Thanks again folks.