Brakes are squealing - after new pads installed, rotors cleaned, brakes bled...?

EsPeGe

Likes Bikes and Dirt
Hi all thought I’d better drag up an old thread rather than cranking up a new one.

So I’ve almost finished my Evil wreckoning build and have been down to Thredbo for a few days to give it a test.

Well the M8000 XT brakes with Uberbike rotors (particularly the front) are howling like banshees. Brand new rotors and pads, zero contamination and bedded in the way I’ve always done it with no previous issues. I even changed the front pads over with a spare set (also brand new) and after a few runs they are screaming again. For someone that works on having the quietest bike possible it’s beyond annoying.

I’ve done some googling and found this.


Anyone tried anything like this? I need to stop this f$&king noise. The next step is changing rotors which I don’t want to do given they are brand spanking new and super matchy colours. I’ve used these rotors before without issue so they’ll be the last resort.

Please help team.

Cheers Scott.
 

stirk

Burner
Personally I would not use stuff like that without knowing what the product was actually doing, it may make the brakes less effective.
 
Z

Zaf

Guest
Running coloured rotors, brake-lines and/or derailleur outers causes a lot of visual noise that the universe matches by trying to draw even more attention to the bike in question through the medium of auditory noise. In most cases it can be resolved by "stealthing it out" to classy levels again.

Good luck.
 

EsPeGe

Likes Bikes and Dirt
Running coloured rotors, brake-lines and/or derailleur outers causes a lot of visual noise that the universe matches by trying to draw even more attention to the bike in question through the medium of auditory noise. In most cases it can be resolved by "stealthing it out" to classy levels again.

Good luck.
Mmmm I didn’t think of that but a good point you raise. But it’s a trade off because everyone knows it’s a scientific fact that if everything matches you are at least 3km/h faster. Although if everything is all stealth then I suppose that could also be deemed as matching...... something to think about.

So mathematically what you are saying is stated as follows:

V (dB) ∝ M{B + N}

Where:
V = Volume in decibels
M = Meterage of cable
B = Brightness of said cable
N = Number of matching items.

That’s an intriguing theory but doesn’t really help stop the noise from pissing me off.

Cheers Scott.
 
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Oddjob

Merry fucking Xmas to you assholes
What pads are you using? Use a good sintered. Merlin has EBC gold cheap. Organic are more likely to glaze and squeal.

I'm assuming that you're 100% positive that there's no oil on your rotors or pads. Use isoprpyl alcohol any time you go near your rotors/brakes.

If you've met those conditions then you probably have a caliper alignment problem. Don't do the standard method. Manually line up the centre line of the front of the caliper with the disc and then tighten the front bolt and repeat for the rear.

If that doesn't work then there is a risky method where you lightly smear copper brake grease on the back of the pads.

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EsPeGe

Likes Bikes and Dirt
What pads are you using? Use a good sintered. Merlin has EBC gold cheap. Organic are more likely to glaze and squeal.
I’m running the Shimano metal pads. Made sure to avoid the organic as I do a lot of gravity riding so I need the longer life from metals plus in general they don’t squeal as much.......

I'm assuming that you're 100% positive that there's no oil on your rotors or pads. Use isoprpyl alcohol any time you go near your rotors/brakes.
Yeah completely positive. I quarantine the pads whenever I work on the brakes, always clean up with brake cleaner or isopropyl alcohol, I use gloves and never touch the pad faces or the rotors. I’ve also checked to make sure nothing is leaking at the calliper and this is backed up by the fact that the brakes are performing really well. Just screaming like a bastard.

If you've met those conditions then you probably have a caliper alignment problem. Don't do the standard method. Manually line up the centre line of the front of the caliper with the disc and then tighten the front bolt and repeat for the rear.
I’ll check this out. I’ve always done the standard method so I’ll give this a crack. Thanks for the suggestion.

Cheers Scott
 

wkkie

It's Not Easy Being Green
I'm running an almost identical setup. Uberbike rotors, Shimano metal pads, M8000 brakes.

I found that the Shimano pads can be noisy at times, the Uberbike race matrix pads are better performing and have less noise.

***** On a separate note, semi related, I have just run into an issue with a Zee caliper and squealing and shuttering at moderate braking. The stopping performance is ok, but noisy and vibration.... :mad:

I've tried different pads, different rotors, checked all the mounting bolts and frame bolts, nothing worked.

I ended up putting the M8000 on the rear for a Buller weekend and had zero issues and the brakes copped a hiding!

I'm thinking it might be an issue with a caliper / piston...? Anything I might have missed?
 

pink poodle

気が狂っている男
The problem with going to a stealth bike os that nobody will pick it up on their bike-dar. Except maybe your wife...which doesn't end well. Making it an n+1 with no real pay off.

Have you considered the age old pad bbq?

And we'll done for using the search.
 

EsPeGe

Likes Bikes and Dirt
The problem with going to a stealth bike os that nobody will pick it up on their bike-dar. Except maybe your wife...which doesn't end well. Making it an n+1 with no real pay off.
All good there mate. Not married.

Have you considered the age old pad bbq?
I hadn't, given they are new pads and that they aren't contaminated. I was under the impression (perhaps incorrectly) that the blow torch was good for maybe recovering stuffed pads that had been contaminated. You reckon it might work here??? I'm thinking if the alignment doesn't work I might get some wet and dry, sand the pads back and try bedding them in again.


And we'll done for using the search.
I know how much you blokes love it when folks start a new thread on the same subject every week.
 

wkkie

It's Not Easy Being Green
Swap your rotors front to back, if they're the same size.... That'll at least rule that out.
 

pink poodle

気が狂っている男
All good there mate. Not married.
Then I don't understand why you haven't just brought new brakes!

I've never bbq'd brake pads. I just recall it.being a popular cure all (and possibly snake oil) on here a few years ago.

Do you have any spacers/washers in the set up? If not maybe a thin shim here and there. If so, perhaps less shims. I had a set not too long ago that ended up with a 1/2mm shim under each end of the calliper. Somehow it just made everything sit right and noise free was had. With all the reverberations and echoes a bike can produce the slightest misalignment cam be very annoying.
 

Plankosaurus

Spongeplank Dalepantski
Then I don't understand why you haven't just brought new brakes!

I've never bbq'd brake pads. I just recall it.being a popular cure all (and possibly snake oil) on here a few years ago.

Do you have any spacers/washers in the set up? If not maybe a thin shim here and there. If so, perhaps less shims. I had a set not too long ago that ended up with a 1/2mm shim under each end of the calliper. Somehow it just made everything sit right and noise free was had. With all the reverberations and echoes a bike can produce the slightest misalignment cam be very annoying.
Cooking brake pads is definitely not snake oil. I was a sceptic too until very recently when I bought those zee brakes and was thoroughly underwhelmed. No amount of cleaning pads and rotors with iso or brake cleaner helped, the brakes were shit.

Out comes the old butane camp stove, hit the pads with brake cleaner one more time, wipe them down, hold them over the flame with pliers till they stop smoking, cool them down, re install, nearly go ass over while trying to bed the now spectacular brakes...

The little rambo stove is a part of my maintenance kit now, fixed all the brakes in the house, even the ones I thought had no problem!

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EsPeGe

Likes Bikes and Dirt
Swap your rotors front to back, if they're the same size.... That'll at least rule that out.
Can't unfortunately. Running 203mm on the front and 180mm on the rear. But good idea to at least isolate the problem to one or the other. I think I may have an old rotor that I can use.
 

EsPeGe

Likes Bikes and Dirt
Do you have any spacers/washers in the set up? If not maybe a thin shim here and there. If so, perhaps less shims. I had a set not too long ago that ended up with a 1/2mm shim under each end of the calliper. Somehow it just made everything sit right and noise free was had. With all the reverberations and echoes a bike can produce the slightest misalignment cam be very annoying.
No spacers except for the half round washers that come with the brake spacer for the front. I spoke with a guy the other day that reckons he shims his pads out using a biscuit tin lid. He gets the pad and draws around it as a template then cuts it out. He swears that it gives really good lever feel. He also adds more as the pads wear which seems logical. Maybe it's worth a try here to see if it stops the noise as well. But you say you had the shims under the caliper? Interesting. You guys are all giving me plenty to look into!!!!

Cheers Scott.
 

pink poodle

気が狂っている男
Add-subtract-tweak-twerk...think of all the spots that bolt on and start shimming. It is about micro adjusting alignment.

Much like your biscuit tin mate, I made some tiny shims from an ice cream bucket millions of years ago in the days before post mount forks. Just needed to budge the brake over a tiny bit. Worked amazing.
 

Mr Crudley

Glock in your sock
Add-subtract-tweak-twerk...think of all the spots that bolt on and start shimming. It is about micro adjusting alignment.
This might be on the right track. Check the clearances between any conical washers, spaces etc on the caliper mount and how far is it from the rotor. Is there enough room to allow for any bending or flexing when braking with enthusiasm.

Is the caliper centred on the rotor or bends it a little towards the caliper mount when grabbing a handful of brake. It might be one of those dynamic things that are hard to find or you may only hear a faint noise of rubbing. Just worth considering.

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EsPeGe

Likes Bikes and Dirt
Cooking brake pads is definitely not snake oil. I was a sceptic too until very recently when I bought those zee brakes and was thoroughly underwhelmed. No amount of cleaning pads and rotors with iso or brake cleaner helped, the brakes were shit.

Out comes the old butane camp stove, hit the pads with brake cleaner one more time, wipe them down, hold them over the flame with pliers till they stop smoking, cool them down, re install, nearly go ass over while trying to bed the now spectacular brakes...

The little rambo stove is a part of my maintenance kit now, fixed all the brakes in the house, even the ones I thought had no problem!
So just to confirm you do this with new pads?
 
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