Avid Brake Howling - name that tune!

cjd000

Hi Everyone,

I've just bought a Boardman FS Team bike and i'm having issues with the rear brake. The bike is this one...

http://www.bikeradar.com/gear/category/bikes/mountain/product/review-boardman-fs-team-11-44849

After a few miles the break starts howling very loudly and only gently holding the brake seems to stop it. I have read other forums on the Avid break problems caused by the rotor. The brakes in question are the Avid Elixir 3's with the HS1 disks (designed to eliminate this very problem!!)

My main question is - with bike only 2 months old, should this be a warranty issue? should i be kicking up a fuss at the shop to get them to solve the problem? being as i've just bought the bike i should not have to pay to replace the disc or any other part to fix what in my opinion is an unusable product? - I'd appreciate some advice on this!

I have audio recordings of the noise but will have to send them to anybody interested as the iphone files are not aloud when i try to upload them.

Things tried so far - in order...

1. Removed pads and carefully placed a small layer of copper grease to the backs (yes i was careful to avoid contamination) - seemed to fix for about 10 miles.
2. Re-aligned calliper
3. Use break disk cleaner - no difference
4. Use Isopropyl Alcohol on disks - no difference
5. Try re-aligning calliper again - no diff
6. New pads (discobrakes) metalic mix, nothing special - no diff
7. Sanded disc - no diff
8. Re-align calliper
9. file 45deg edge to each pad - no difference
10. sand pads using 200grit - no difference

11..... chuck £1000 bike in the bin because i can't enjoy using it at the moment!!


Other than new pedals by the second ride, and the brake issue its a great bike!

Thanks,

Chris

nicklouse

Well as you have already played with it the supplier can tell you to take a jump.

And the noise does come and go. The same as most disc brakes wether on a car or a MC. Or a bike.

A change of rotor size or brake makers can fix it.

I had one set of brakes that could not be fixed on one bike but were fine on another but with different sized rotors.

Some times the resonance is just there.

cjd000

I'm finding on other forums that there seems to be a general problem with Avid brakes.

One site says that Avid have made a few fix kits which they will send if contacted. Trubble is I can't find any way to contact them.

On the plus the halfords first service is due so I'll be bringing it up with them.

Chris

Chunkers1980

This forum says just use them.

nicklouse

cjd000 wrote:

I'm finding on other forums that there seems to be a general problem with Avid brakes.

One site says that Avid have made a few fix kits which they will send if contacted. Trubble is I can't find any way to contact them.

On the plus the halfords first service is due so I'll be bringing it up with them.

Chris

You don't contact them as they do not deal with the public.

You deal with the retailer. That is who your agreement is with.

Not head of any fix kits. Other than the solid brake tracked disc.

Tbh just use them.

cjd000

The trubble is they are unusable. The noise gets too loud and it's a continuous high pitch tone.

Chunkers1980

Have you tried braking less?

waby1234

My Avid brakes sometimes squeal, especially after getting wet. Try some big heavy stops to get some heat into the pads and discs.

cjd000

Not quite as constructive as I hoped!! To silence the noise I have to apply the brake! So braking less will just make it worse

I have some very thin gasket paper - any thoughts on glueing a piece to the back of a pad?

Also I really have to emphasis this is not the normal 'squeal when wet' type of problem. It's a continuos resonance through the frame all the time you are riding regardless of speed (go faster makes it louder!)

Chunkers1980

Use the one that makes the most noise least?

cjd000

Sorry 'chunkers1980' you really are missing the point!!

I have a continuously howling brake, using it less makes no difference and kind of defeats the object of putting brakes on a bike!!! Its not effected by water, or heat, just riding it isn't the answer as I want to keep my hearing and not turn heads as i ride. I've tried riding though it to see if the brakes bed in better but over a 30mile ride it stayed consistently the same.

Giraffoto

I'm sorry if this appears to be a silly question, but are you saying that when you just ride normally, not even touching the brakes, they're making this noise? Because if that's what's happening you do have an issue. The pads are meant to be pushed clear of the disk when you're not using them for braking - the first thing I'd be checking is the spring arrangement that's meant to be doing this for you (that's just a visual "is it there?" check)

paulmgreen

Yes exactly..... If ts all the time without even applying them... Then something must be touching somewhere! a few suggestions.....

Have you tried removing the rotor off the wheel and repositioning in a different position?

Have you tried swapping rotors from each wheel ...... If the noise moves to the other wheel then the rotor is at the cause?

Do you know anyone with a rotor you could borrow to swap over and test any difference?

Examine the rotor really closely .... Are there any rub marks anywhere other than on the actual braking surface?

The Rookie

A whine/whistle/screech is usually something resonating, my Juicy's were noisy until I fitted a different (stiffer/heavier) discs (was on alligators) but the one thing it shouldn't do is make a noise when not braking, sounds like the calliper may be misaligned or you have a sticky piston.

cjd000

Guys, i checked the pads today as i spun the wheel. I can clearly see a gap on one side of the rotor (between pad and rotor) but not the other.

As the wheel spins freely i just assumed there was a gap albeit very small.

Tried re-positioning the calliper but it always seems to be the same. I've seen a thread that suggests putting a piece of card either side of the rotor when adjusting the callipers - would this work? or is it likely to be that the piston is not working correctly on one side? the spring seems fine.

I have this in with halfords for its first service on Tuesday. I may opt not to mess any further and just bring it up with them.

Chunkers1980

Let Halfords do it.

oxocube1

This will tell you everything you need to know on how to sort the howling::

http://www.pinkbike.com/news/Tech-Tuesd ... -2011.html

Pretty informative article and quotes the founder of Avid brakes.

The bottom line is, the bedding in period of the brakes is the most important period of time for them. You need to 'pair' the pads and rotors by transferring pad material onto it's appropriate rotor and this needs to be done properly otherwise you will get howling/squeaking. By the sounds of it your brakes have not been 'bedded in' properly.

The Rookie

As all that relates to howling when breaking it's not of relevance. They should not howl without braking, fact, fix the fact the brakes are binding on, however slightly, and it won't howl! Even when mine howled like a banshee (sintered and alligators are a very prone combo especially as soon as they get at all warm) they were silent with no brakes applied.

mintedox

One of my elixir 3's did this for a while and it did my head in, then it just went away and hasn't come back.
I'm guessing it lasted about 40-50 miles.

logie48

cjd000 wrote:

Hi Everyone,

I've just bought a Boardman FS Team bike and i'm having issues with the rear brake. The bike is this one...

http://www.bikeradar.com/gear/category/bikes/mountain/product/review-boardman-fs-team-11-44849

After a few miles the break starts howling very loudly and only gently holding the brake seems to stop it. I have read other forums on the Avid break problems caused by the rotor. The brakes in question are the Avid Elixir 3's with the HS1 disks (designed to eliminate this very problem!!)

My main question is - with bike only 2 months old, should this be a warranty issue? should i be kicking up a fuss at the shop to get them to solve the problem? being as i've just bought the bike i should not have to pay to replace the disc or any other part to fix what in my opinion is an unusable product? - I'd appreciate some advice on this!

I have audio recordings of the noise but will have to send them to anybody interested as the iphone files are not aloud when i try to upload them.

Things tried so far - in order...

1. Removed pads and carefully placed a small layer of copper grease to the backs (yes i was careful to avoid contamination) - seemed to fix for about 10 miles.
2. Re-aligned calliper
3. Use break disk cleaner - no difference
4. Use Isopropyl Alcohol on disks - no difference
5. Try re-aligning calliper again - no diff
6. New pads (discobrakes) metalic mix, nothing special - no diff
7. Sanded disc - no diff
8. Re-align calliper
9. file 45deg edge to each pad - no difference
10. sand pads using 200grit - no difference

11..... chuck £1000 bike in the bin because i can't enjoy using it at the moment!!


Other than new pedals by the second ride, and the brake issue its a great bike!

Thanks,

Chris

I have the exact same problem with my boardman cx team. Avid BB5 brakes. Mines howl when cycling. I need to tap the rear to stop it, but only lasts for 5 seconds then comes back again.

Only been out a few times, so maybe they are not bedded in properly.

The Rookie

How do you think balance affects it's ability to resonate? That so bizarre as to be yet more trolling.

What that indicated wa sthat the Avid disc had an easier to achieve (input) resonant frequancy.

Chunkers1980

What a tool.

The Rookie

I find most real tools have their uses, you insult my hammer, and I can think of a great use for it right now.....

Ghostt

I had the exact same problem on a set of Elixir 3's. Turned out to be a rather easy fix actually.

Step 1: Remove the brakes from the bike. Bin 'em, ebay them or relegate them to pub bike duties.

Step 2: Install anything made by Shimano or Formula.

Seriously, though, I've a set of Deores and a set of RX's, both running perfectly after a year and numerous sets of pads. Formulas required a bleed out the box other than that perfect.

cooldad

Christ is it that time again? Mong hour.
Night all before my head explodes.

The Rookie

Resonant frequance is usually expressed as a function of stiffness (admittedly the inverse of elasticity) and mass, 'balance' (usually referring to rotationaly balanced) has nowt to do with it, you seem to be changing your tune 9pun intended).

Winding the solder round it changed the mass, as it's soft it also increases hystersis and therefore would act as a damper.

You don't need and axis of symmetry per se, hold a ruler over the edge of a table and ping it, watch it resonate....it's making a noise (just outside the audible spectrum), that same ruler could be all hacked about with no possible symmetry and it would still resonate.

Troll or Fwit, still not convinced, I came expecting a battle of wits, not twits!

cooldad

cyd190468 wrote:

Do I need to use simpler words? Which bit didn't you guys understand? Maybe get some-one with a physics A-level to explain what resonance means. Here's some home work 1) look up superposition 2) Look up the difference between constructive and destructive interference and it should become obvious why a perfectly balanced disc is more likely to howl than a slightly unbalanced disc.

There's only one unbalanced thing around here.
FFS it's a mountain bike, not a piano. It's not important - a bit of crud will sort it out.

Giraffoto

The Beginner wrote:

Resonant frequance is usually expressed as a function of stiffness (admittedly the inverse of elasticity) and mass. . .

So, you wouldn't express it in Hertz then?

The OP's problem was that his pads were rubbing on the disc when he wasn't braking - weird tuning and balancing rituals aren't as likely to fix that as getting his caliper working properly.

mrmonkfinger

Has the OP tried a different disc yet?

Or aligning the caliper by eye (after messing about with the avid cps "it does it automatically" idea)?

Giraffoto

The OP last contributed to this thread around the start of August - it's lain dormant since then until it got resurrected a few days ago, and degenerated into a debate about resonance in discs. The OP was last seen heading towards Halfords to get it sorted out (it was a newish Boardman, I think) and has probably been riding a silent bike since his last post

The Rookie

Giraffoto wrote:

So, you wouldn't express it in Hertz then?

The OP's problem was that his pads were rubbing on the disc when he wasn't braking - weird tuning and balancing rituals aren't as likely to fix that as getting his caliper working properly.

I was referring to elsaticity versus siffness as was clear, the SI unit is Hz, there are others of course, the unit is not 'expressing it as either'!

Agreed, it was fwit cyd that started on balance and shite....