My front LX brake is making an awful squawking/squealing noise, particularly at low speeds. The brake works but the noise is bizarre. The only major change preceeding this was a change of disc brake pads from stock organic Shimanos to aluminium backed A2Zs. I’ve just popped the pads out and wear is even, the caliper is aligned and I’m convinced that it’s the pads themselve. I was under the impression that I’d bough organic A2Zs as the listing states that they’re made from organic material with a ‘special’ compund. The organic pads I have for my BB7s on my other bike have plain grey braking material, but after taking another look at the A2Zs for the LXs the braking material is highly flecked with copper colour metal. I’ve fished out the packaged A2Z pads I have and they’re acutally listed as ‘Kevlar composite’, whatever that means.

So, can a change in braking compound make such a difference to noise generation and what exactly is kelvar composite (I thought that only sintered pads had metal in the braking material)? They seem to stop the bike ok.

As suggested by Tandem Jerry in an early thread, I’ve sanded them down and will try re-bedding to see if that helps.

I have some M486’s which are similar to LX and also had this problem (with sintered pads). Usually it is a sign of contaminated pads, so take them off and sand them down a little, and heat them up over an oven to burn off contaminants, spray with discbrake cleaner afterwards and put them back. Worked for me!

They shouldn’t be contaminated, I managed to contaminate the Shimano pads by dripping suspension oil whilst lubing my fork stanchions. I ditched the Shimano pads and thoroughly cleaned the rotor with white spirit (which I’ve always used to clean rotors) before fitting the A2Zs. I could get some proper disc brake cleaner if it does a better job.

Anyway I’ve sanded down the pads a little so we’ll see if that helps.