New brakes making screeching sounds?!

hey guys,

wanted some advice on some front brakes shoes i just got this morning from PBK.
sort of brake system: front shimano 105

after tightening the allen bolts up and making sure it's aligning correctly to the rim, 1mm just below the top of the rim, i went on the bike and at slow speed pressed on the brake lever quite hard to see how sharp those new brake pads were... it sorta was efficient up until full stop when it made a screenching LOUD noise!! just like the ones u hear on the road when people have old brakes or something like that...

do u think they need to be used a bit before they stop making that noise? I feel those brakes are not really efficient:

http://www.probikekit.com/display.php?code=a0061

brakes?

i may be wrong but maybe they just need to be worn in?

probably need to wear in,
10mm below the top of the rim???????/

Maybe you have a sheen on your rim, burnishing slightly with light sandpaper or bike-shop burnishing stone could help.

Great as a pedestrian-warning system though.

o my bad, i meant 1mm :P

i'll try to smooth out technique thing - how do u guys usually clean this part anyways? just dry paper? :O

could give the rubber a rub with sand paper. also are they sitting square when you pull the lever, sighting from the front of the bike??

mm ill go check next time i go for a fag break! :P its weird tho, they make the noise only when the wheel is about to stop completely, not when i first brake, not when i slow down, but when i 'stop'

''squeal like a pig boy"

Are the brake pads properly toe-d in?

^^ sounds like they need toeing in. i wrap a lacky band round the back of each pad and then place them and tighten up. works a treat.

My thoughts are pretty similar to Object17's:

i) Your rims are reet dirty and could do with a clean
ii) Or your pads aren't property aligned and are touching the rim all at once - though you'd normally get squealing throughout braking not just at the very end.
iii) Or they'll quickly wear in and the problem will just disappear (surface of pad could have been contaminated with something)

Toe them in !

Looking from above, make sure the front edge of the pad touches the rim fractionally before the back edge - if the pads are parallel with the rim then they will make contact all at once and often squeel.

Yeah, if the pads are toed in properly, I think I'd want to clean the rims with alcohol and make sure that they're grease-free.

Man, the squeaking is the best. I used to have Magura HS33's with Kool's and they're even better than a horn. And more fun.

Trials setup: Magura HS33s, Plazmatic pads, tarred rims.. EEERK! EEERK! EEERK!EEERK! EEEEERK! :)

Just got some new rims... but now every time I pull hard on my front brake, it emits a very loud very high pitched screeching noise as the pads rub against the rim. It sets the teeth on edge of every ped within 500m and it's only a matter of time before I shatter a nearby window. My first thought is to cover the pads and rim with plenty of grease but does anyone have a better idea? thx.

Rims don't have a braking surface?

Have you adjusted the pads with toe-in or flat against the rim?

Lightly oil the rim and brake block. The screeching will dissapear, stopping distances will increase slightly.

Disclaimer.

Repped.

matt_rp are the blocks contacting the rim at the same time in the levering? Adjust to make them grip the wheel together, if not.

Prav do you actually bend the brake shoe to 'toe in' or the caliper? Never worked this out.

skully - caliper

matt - try lightly sanding the circumference of the rim where the brakes make contact, this should give a better surface for braking and will often get rid of brake squeal. also try sanding the braking surface of the pads slightly

Depends - I've never had to do anything to my Shimano caliper brakes to be honest.
I used a large adjustable spanner to very slightly toe-in the arms of super-cheapo calipers.
V-brakes have conical washer setups so you dont need to do anything fancy.

The pads quite well aligned but not immaculately so... one of them has a bit of toe-in, the other is flatter against the wheel. If it's that simple, I'll have a play with them, thanks.

@tomasito, if it's not the rim that the brakes press against, what is it? Not being sarky - I thought it was the rim.