squealing brakes
- Thread starter dynoram
- Start date
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Squealing happens due to vibration, and vibration can be caused by loose bolts or other fittings in the brake caliper. On the other hand nothing may be loose at all, and you may just need to toe-in your brake pads or wait for them to bed in (if rim brakes).
If disc brakes, a dab of copperslip on the back of the brake pads not on the braking surface will often fix squeal.
What sort of brakes are we talking about here - Is the bike new, or have you recently fitted new brake pads/adjusted the brakes?
If disc brakes, a dab of copperslip on the back of the brake pads not on the braking surface will often fix squeal.
What sort of brakes are we talking about here - Is the bike new, or have you recently fitted new brake pads/adjusted the brakes?
Globalti
Legendary Member
Brakes squeal because there is always a certain amount of flexibility in the arms holding the pads. When you brake the rim pulls the pads forwards and distorts the arms, allowing the pads to lose contact partially with the rims. Having lost contact they spring back then grab again and the same sequence is repeated, often fast enough to set up a loud vibration or squeal.
To prevent it, the pads need to be toed in, i.e. set up on the arms so that the fronts contact the rims before the rears, this will pull the pads into the rims so that, at the elastic limit of the arms the pads are more or less parallel and grabbing at their hardest. To do this, loosen the pad bolt and clamp the pads against the rim by squeezing the brake arms together while trapping a couple of thicknesses of a cereal packet lid at the backs of the pads. Gently tighten the bolts ensuring the pads don't move then nip them up tight. A bit of grease on the bolts might help you to get them tight without displacing the pads.
To prevent it, the pads need to be toed in, i.e. set up on the arms so that the fronts contact the rims before the rears, this will pull the pads into the rims so that, at the elastic limit of the arms the pads are more or less parallel and grabbing at their hardest. To do this, loosen the pad bolt and clamp the pads against the rim by squeezing the brake arms together while trapping a couple of thicknesses of a cereal packet lid at the backs of the pads. Gently tighten the bolts ensuring the pads don't move then nip them up tight. A bit of grease on the bolts might help you to get them tight without displacing the pads.
Jdratcliffe
Well-Known Member
- Location
- Redhill, Surrey
or have you recently washed/cleaned your bike? i got some muc off on my roadies rims and the noise was HORRIFIC until i worn it off on a long hill ( took three times todo so)
2Loose
Guru
- Location
- Loughborough, Leicestershire.
My Magura hydraulic rim brakes start to squeal when I haven't cleaned the rims for a while, but the reasons given above are more usual.
Rim brakes will squeal if not toed in properly, or if there is any grease/oil on the rim. To toe in the end nearer the front of the bike should be closer than the rear end. Having said that, my touring bike has squealing rear brakes despite using different rims, blocks and even brakes over time! I suspect that one of the pegs supporting the cantilever is a bit skimpy!