Noisy Campagnolo Record front brake

[PerB]

I have a terrible noisy front brake on my DBS La Migliore with Camapgholo Super Record brakes. The rear brake is normal quiet with the same brakes, pads and rim!

What is going on here?

The brake set up is shown here:


The wheel set on the bike now is with a set of Nisi Solidal rims, They are dark grey anodized. http://www.velobase.com/ViewComponent.a ... AbsPos=224

I used the this wheels on two other bikes last year and on my Mafac Racer equipped bike they where terrible noisy, The Mafac brakes are known for being noisy and thus I did not bother to much. I later put the same wheels on my Rossin Ghibli with Camapgnolo Chorus (first generation) brakes and there where no noise whatsoever.

 

[mattr]

What sort of noise is it? Howling, juddering?

 

[PerB]

Its a high pitch howling noise,

 

[originalshinkicker]

I don't know if it is just the camera angle but that brake block looks like it needs to have more 'toe-in' - It looks like the rear of the shoe is hitting the rim first - that will often cause a huge squeal. Get the front of the shoe to touch the rim first.

 

[PerB]

Re:

Thanks for explaining, but is there any adjustment for the toe in on this brakes other than twisting the arms?

 

[originalshinkicker]

If there are no curved washers then the only option is to bend/twist the arm - twisting brake arms is perfectly normal.

 

[Boscarn]

Re:

I had a problem with some Campag Brakes that had the same white brake blocks as show in your photo. I was alarmed how bad the braking was; the blocks had gone hard and I replaced them and braking was restored. I would try a substitute set of blocks and see if the problem goes.

I have made the assumption that the callipers are adjusted correctly.......

The caliper arms can be twisted to alter the toe in, use an adjustable spanner on the shoe holder part and gently twist them as required.

 

[PerB]

Thanks for all kind replies, I will have a look at the toe in adjustment. The braking action is very good on this bike,I need to be careful not to leave the bike head first when braking! I believe there is nothing wrong with the bake blocks, but I shall keep that in mind as well.

 

[Midlife]

You can "toe-in" by sanding down the blocks at an angle if you don't want to use a spanner on the calliper...........bit wasteful though

Shaun

 

[gfk_velo]

Re:

If it were me:

• Check the brake spindle is straight - if the bike has been crashed, sometimes the spindle gets bent to the left where the adjuster side whips round and impacts the downtube.
  Check the two nuts on the front of the brake are tight against one another and that there is no play between the two caliper arms.
  Brake blocks off and check for any bits of material embedded in the brake block.
  Check brake fixing bolt is fully tight and that the washers between the fork crown and the caliper are there & in one piece.
  Set block heights so both blocks strike rim at the same height.
  Set caliper so that both blocks hit the rim at the same time (does not necessarily mean that they will start the same distance from the rim)
  Toe in as others have suggested.
  Set the gap rim to block 1 - 2 mm - too close or too far and you loose efficiency as you change the mechanical advantage of the lever / caliper system.
  Use a Mavic cleaning pad to clean the braking surfaces off.

That will do it and give you the best possible braking with those pads, on that rim.

Any, or any combination, of the above, barring an inefficient block to rim position, can cause squeal - it's caused by the brake biting and releasing the rim at the same frequency that will allow the rim to resonate, without the damping of both blocks being fully and evenly applied.

Toe-in allows the rim to effectively "pull" the full length of the brake block into engagement with the rim, so it increases the efficiency of the brake, as well as depressing noise.

I'd get the toe in by sanding the blocks (though in point of fact I'd use a file that is only used for this job - "sand"paper, generally actually "glass"paper, can leave bits of glass embedded in the block and if you use a file that's also used for metalwork - well, I guess the rest is obvious). If you tweak the caliper, which is common (and if carefully done, usually fairly safe) practice, you can't repeat it for a new set of blocks, whereas by removing a small amount of block material (we are talking about a full-width sliver, starting at zero thickness at the nose and no more than 1 mm deep by the extreme tail of the block), if you install new blocks and they are "out" in some other way, you can just doctor them rather than having to worry about bending the caliper again, which gets to be a progressively worse and worse idea the more times you do it.

Bear in mind, even "back in the day", pad materials and rim materials varied and sometimes it's just a bad combination - this one you should be OK with, though.