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Disk brakes howl. We all know that, and that some brakes do it more than others.
We also know the conditions that cause it and the magic incantations to stop it temporarily.
My experience is that doing all the cleaning of surfaces etc works temporarily, but the noise returns eventually. The howling doesn't seem to affect the power of the braking.
What interests me is what on a bike creates the noise.
It is mechanically created, something has to be vibrating at high frequency, so which component/s?
1. Is it the brake pads?
2. Is it the actual disk?
If there was a way to damp the responsible component, that might cut the noise out altogether.
Car brakes used to howl, and that was cured by applying a dab of anti squeal paste to the back of the pads to stop it.
Before I go and try some, anyone using it successfully with bike brakes?
(Looking at Liqui Moly 3077 Anti-Squeak Brake Paste)
Are there any brakes that do not howl?
It's all to do with correct "bedding in" of brakes, meaning encouraging transfer of pad material to the hot disc. Most mountain bikers don't get to deal with this because their brakes are continually abraded by a mixture of water and grit.
I find my XT's howl until they've dried off and warmed up a bit, After that, silence is golden.
My Kevlar pads howled until I changed them for semi sintered. And tightened the bottom bolt to more than finger tight ☹️
I kind of like it, makes me brake less, don't want my riding buddies to know how cowardly i am.
On the gravel bike the cause seems to be a particular blend of slop with probably the right amount of horse shit mixed in.Once it clears it's back to normal silent or grinding
And just realised at the weekend, I'm still on the original M8000 finned pads that came with the Brawnson, April 2017....
I think it's probably a really complex interaction between the pads, caliper, disk, hub, spokes, frame, etc. Something in there has a resonant frequency that matches the vibration of the pads on the disk. Problem is that what works on one bike might make no difference on another. I actually think howling brakes are a great feature for clearing old people out of the way so I've never actually tried to fix it. I would like to know how to guarrantee it to occur though, so if anyone has any tips on that, they'd be welcome.
Resonance for sure can be a factor, looseness and the interaction between pad and disk, poor alignment and also external contaminants, water, grit, jobbies....
Liqui Moly 3077 Anti-Squeak Brake Paste
Permeates through the holes in the backing plate and into the friction material
Leave it alone!
It's an early warning alarm to alert others there's a middle to elderly aged fatbike bore coming along in around 8 or 9 minutes time.
I hate howling brakes and non of my bikes do it bar very occasionally. Sintered pads, small discs, braking in hard short bursts
From what I have read its a slip / grip / slip cycle repeated at high frequency as you brake. I have had it and when it happens the brake effectivness is greatly reduced.
Disc brakes create friction from a mix of adherent and abrasive friction. When you get these two acting in different amounts on different parts of the disc is when you get it. It is made louder by resonance in the disc, fork, frame.
Some types of pad and brake are more prone as they have a different mix of the two types of friction. YOu also can get "cold polishing" of pads - a pad that never gets up to operating temperature gets a surface layer that does not grip properly - this again increases the chances of break squeal as its a polished surface against a polished surface
My recipe for avoiding it is to use the smallest disc you can so it runs as hot as possible and to use the brakes hard in short bursts.
Road contamination also gives a higher chance of getting it. On my commuter I have had it from road contamination. My cure oddly enough was to hold the brake on at a point just below that the howl occurred and thus break up the deposit on the disc surface
Its complex and multifactorial but it is not inevitable.
Am preparing to experiment with anti-squeel pads, problem is they're approx 0.5mm thick so I think they'll only work with cable brakes, and even then you need to remove the pad adjusters on my TRP Spyres which means adjustment via barrel adjusters.
Result = Silent brakes (I hope) but less power due to clumsy adjustment.
Was interested in the smaller rotor theory, but it's surprisingly difficult to retrofit 140mm rotors unless the bike comes designed with them, I'm hoping the newer crop of gravel bikes with flatmount brakes make this a bit easier.
Road contamination also gives a higher chance of getting it. On my commuter I have had it from road contamination. My cure oddly enough was to hold the brake on at a point just below that the howl occurred and thus break up the deposit on the disc surface
Only disk brakes I have that squeal are on my commuter. And its normally the rear which gets the majority of the contamination which squeals the most.
Getting the disks and pads really hot can help get rid of it.
Roll down a slight hill, drag the brakes enough to stop you speeding up. Now pedal HARD, and increase pressure on the brakes. This should get the disk and pads pretty hot. Jump off and squirt some water on the pads. It should sizzle. Repeat until the brakes don't squeal any more.
Works pretty well for light contamination.
I hate howling brakes and non of my bikes do it bar very occasionally.
Times have changed then.
It’s an early warning alarm to alert others there’s a middle to elderly aged fatbike bore coming along in around 8 or 9 minutes time.
Proper Lol!
I hate howling brakes and non of my bikes do it bar very occasionally.
Surely you don't do much baking in the 1 mile commute of yours? 😉
geex
Leave it alone!
It’s an early warning alarm to alert others there’s a middle to elderly aged fatbike bore coming along in around 8 or 9 minutes time.
Ouch! That's a bit personal.
BTW I think elderly is the description. 🙂
Are there any brakes that do not howl?
Every single disc brake I've ever owned.
Rim brakes, on the other hand… now there's howling.
Are there any brakes that do not howl?
A friend was kind enough to lube my rear brakes while he was spraying chain lube randomly at my bike, completely unasked for, I guess he thought he was being helpful. They definitely did not howl, but they weren't really brakes though either.
I find a quick rub around with gt86 brake cleaner gets rid of most of the howl.
NO beer - my old commuter from my old commute which was leith to liberton. Nowadays I use the hipsterfixietwerpbike with caliper rim "brakes"
Scotroutes. I take it you remember a time when my brakes howled? Your memory must better than mine 'cos I don't remember this. Must be the dementia again
3) I've got the bad touch, no matter what I do my brakes squeal. Doesn't happen if I work on anyone else's bike, still happens if someone else works on my bike, I think I was built on an indian burial ground or something.
I just ignore it mostly.
Northwind
I’ve got the bad touch, no matter what I do my brakes squeal. Doesn’t happen if I work on anyone else’s bike, still happens if someone else works on my bike, I think I was built on an indian burial ground or something.
🙂 That could be the problem, those damned Indian burial grounds.
I do all the anti squeal stuff and my brakes start out ok, but it doesn't take long and the noise is back.
My real problem is I'm doing the WEMBO 24 Hour Solos in 2 weeks, and while my bike will be silent to start with, those Ft William descents are going to be really unpleasant if I have to listen to that racket for 23 hours.
What I'm chasing is a permanent cure rather than a temporary one or even one that'll last at least 24 hours.
I suppose I could fit drum brakes...
I have had the problem on various bikes.
I find proper bedding in does help; as above getting them warm and applying them in an on/off fashion helped. A bit of grit or mud does help if they feel like they are not bedded in, as it roughs up the surface again.
I have just got back from a weekend in the Alps; my Bfe has a 160mm rear brake and it got too hot; braking performance still ok but I was dragging the brake loads and had to cool it pretty regularly. The rear would begin to howl when getting hot, but I wonder if the pads were glazing over and reverberating. 200mm front was fine.
I wonder if cutting some fine slots in the pads would change the harmonics.
Doesn't happen to my Hope Mono Minis or Shimano XT unless they get wet. But I am picky so I clean them every bike wash by spraying on bike cleaner, ride a bit with brakes on to rub it all in then hose off.
For me that keeps everything running perfectly. I do bed new pads in though, they barely work if I don't.
I have no answer to it, but I do agree with TJ that cold has a large bearing on noise. Mine howl worst on slushy rides where
A) Speeds are low
B) The disc is well splatted with frozen muck
I tried smaller discs last winter but it didn't make an appreciable difference.
Earplugs?
You just need to toe the pads in.
You just need to toe the pads in.
Surely you could achieve the same effect by carefully warping the rotor so it's wavy.
hols2
Surely you could achieve the same effect by carefully warping the rotor so it’s wavy.
Genius idea, makes you wonder why no one else has thought of it.
Do you think a pastry crimper would be robust enough for the job? 🙂
The front brake on mine is horrendous. Sounds like a robot being tortured whilst a ZX81 loads a game in the background. I’ve tried everything, bar buying a new brake and nothing has cured it. I’ve grown to like it through having no other choice.
Really can’t wait to start night riding just to see if I can end up in the local paper. Walkers report hideous unearthly screams in Macclesfield Forest.