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Squealing Front Brakes

Discussion in 'Bicycle Mechanics and Repairs' started by pw2389, 24 Dec 2007.

  1. pw2389

    pw2389 New Member

    My touring bike has been in the garage for the last 5 months and so I took it out for a spin today. Alas, the front brakes seemed to have developed a horrible squeal. Any clues on the causes and possible cures for this embarrassing condition? :smile:

    Many thanks in advance.
     
  2. Brake squeeeeeeeeel is a sonic reverberation caused by the leading edge of your pads gripping the rim (or disc) and releasing very many times a second. Assuming your braking surface is free of contaminants such as tar or general mank it's a simple case of adjusting your pads so that the trailing (or front) edge of the brake pad hits the rim first. Its called 'toe-in'. The best way to visualise it is to imagine that your rim is a fluid passing through a funnel. The pads are the sides of the funnel. A gap of 1mm to 3mm should shut the feckers up depending on the amount of flex or bearing play in your calipers or cantis.
     
  3. Dave5N

    Dave5N Über Member

    Put a thick rubber band round the blocks at the back when you set them. When they are tight, take it off.

    I have a fancy gadget but a rubber band works fine.
     
  4. A fancy gadget eh?
     
  5. Dave5N

    Dave5N Über Member

    Don't lower the tone. This is a nice neighbourhood and I wouldn't want to upset my newfound friends by encouraging lewdness and innuendo.
     
  6. So back to lowering the tone:tongue: whats the fancy gadget you have?
     
  7. Dave5N

    Dave5N Über Member

    It's basically two bits of plastic, joined with a hinge. At each end is a 1.5mm plate set perpendicular to the arms. These go under the pads at the back when you set them.
     
  8. Smokin Joe

    Smokin Joe Legendary Member

    I disagree about squealing being caused by not having the blocks toed in. If the rear of the blocks hit the rim first it will cause the breaks to judder, but squealing is caused either by new blocks needing to have the surface scrubbed in or dirty rims.
     
  9. Squealing is judder, the higher the tone the faster the judder.

    Perhaps you could tell me why my well bedded in blocks squeal on perfectly clean ceramic rims.
     
  10. Dave5N

    Dave5N Über Member

    Fact is, if your brakes squeal, toeing in (caveat -always for me) cures it.

    Harder with cantis. But the're rubbish anyway. I have seen (I haven't really) oil tankers stop in a shorter distance than my 'cross bike.
     
  11. Smokin Joe

    Smokin Joe Legendary Member

    Don't know. :wacko:
     
  12. Lower the straddle hanger on the brake cable, it increases the leverage.
     
  13. Dave5N

    Dave5N Über Member

    I know. They are still rubbish.
     
  14. piedwagtail91

    piedwagtail91 Über Member

    After reading this i'm begining to think that i must be the only one in the country who sets blocks parallel to the rim with no squeal.
    in 30 years i've never toed in brake blocks.
    to set i leave the shoes/blocks slightly loose on both sides of the rim, then pull the brake lever tight and set the blocks for height and tighten up the bolt, leaving them parallel to the rim.
    i do clean the rims and run a cloth between the rim and block to clean it after every ride.
     


  15. Before you clean your bike get a sheet of paper and put it on the rim. Now pull your brake just so it touches the paper and then have a look at the mark and then tell us your brakes are not toed in!