Wednesday, 9 October 2013

Rotor squeal dilemas.

Burn baby burn
I've heard hundreds of implausible ways of stopping the annoying squealing sound you get on hydraulic bicycle brakes. So far, non of these old wives tales have ever paid off.  I tried the above photo method recently, I can't remember where I heard it but it was from a fairly reliable source. I'll try anything I suppose, I just wan't to know how to get the job done. 

'Set the rotor on fire with lighter fluid' plausible I guess, apparently all the contaminates get burned away in one fell swoop leaving you with a perfectly oil free rotor and no more fog horn effect every time you brake. It didn't work.

I tried it a few times with a few different set ups and every time it didn't work. Booster managed to burn his hand on a rotor, and we probably inhaled some awful gasses we shouldn't have but the squeal sound retuned after a few minutes riding even with brand new pads. No good.

The only sure fire way of stopping the sound is replacement of pad and rotor together.

I'm under the impression that the squealing sound is produced by micro inconsistencies in the rotor that cause it to resonate at speed, the frame or fork of your bike amplifies the sound. It can also be caused by the presence of chain lubricant or brake fluid on the rotor or pads.

If resonating is the case surely some kind of rubber dampening is needed. I tried making a rubber sleeve to go over the spacing spring between the two pads on a shimano system once in an attempt to dull the resonance, it didn't work.

Everyone recommends copper slipping the back of the pads, this doesn't work.

Put coke on your rotor? it doesn't work.

Sand paper your pads? it doesn't work.

Sand paper your pads, clean your rotor with official non residue rotor cleaner? It doesn't work.

As above but use pure alcohol, it doesn't work.

As above but when you take out the bike brake solidly and consistently for the first 20 tries putting down a new layer of pad on the rotor to remove these inconsistencies? This sounded very good and like it might work. It didn't.

I'm beginning to think that no one has the answer.

I was talking to a guy yesterday, he said he was going to try and cut slits in the face of his pad to see if it stops the resonance, he's getting back to me but I can't see it working, I've seen plenty of damaged pads that squeak, I can't see a purposely slitted pad be any different.

The search continues........

My cross country bike, the front brake squeaks really bad in the wet, but is fine the rest of the time. I can deal with it.

1 comment:

  1. Sand disc and pad lightly with sanding block
    Then degrease both and bed pads in correctly.

    Brake squeal is generally a symptom of poorly bed in pads. During the bed in period material from the pad transfers to the rotor, not following the bedding in procedure can cause irregularities in the material transfer. Which then causes the brake to squeal. Removing this material and starting again should cure the problem.