Brake Pad Direction?

Discussion in 'Cycling Equipment' started by Frank Didomenic, Mar 13, 2003.

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  1. With asymmetrical brake pads does the longer end of the pad extend toward the front or to the rear
    of the bike? A diagram on page 32-16 of Barnett's Manual shows them extending to the front, but I
    think this is wrong. Which way?

    Frank DiDomenico Selkirk NY
     
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  2. Frank DiDomenico queried:

    > With asymmetrical brake pads does the longer end of the pad extend toward the front or to the
    > rear of the bike? A diagram on page 32-16 of Barnett's Manual shows them extending to the
    > front, but I think this is wrong. Which way?

    For best braking performance, the long part should face the rear. Sometimes people reverse the front
    one becaue of clearance issues with the fork blades.

    Sheldon "Kool Stop Salmon" Brown +--------------------------------------------------------+
    | It is one of the superstitions of the human mind | to have imagined that virginity could be a
    | virtue. | -- Voltaire |
    +--------------------------------------------------------+ Harris Cyclery, West Newton,
    Massachusetts Phone 617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts
    shipped Worldwide http://captainbike.com http://sheldonbrown.com
     
  3. S. Anderson

    S. Anderson Guest

    Longer end to the rear...that's how I've always done it..seen it done.

    Cheers,

    Scott..
    --
    Scott Anderson

    "Frank DiDomenico" <[email protected]> wrote in message news:BA96BC30.2C493%[email protected]...
    > With asymmetrical brake pads does the longer end of the pad extend toward the front or to the
    > rear of the bike? A diagram on page 32-16 of Barnett's Manual shows them extending to the
    > front, but I think this is wrong. Which way?
    >
    > Frank DiDomenico Selkirk NY
     
  4. Jobst Brandt

    Jobst Brandt Guest

    Frank DiDomenico writes:

    > With asymmetrical brake pads does the longer end of the pad extend toward the front or to the rear
    > of the bike? A diagram on page 32-16 of Barnett's Manual shows them extending to the front, but I
    > think this is wrong. Which way?

    The asymmetry is there to put the center of pressure in the middle of the pad, something symmetrical
    pads do not do as the toe-in of used pads proves. That toe-in is a good feature seems to have been
    missed by the asymmetry folks. If you look at the caliper arm as being torsionally flexible, it
    should be apparent that they twist from brake pad forces that are at about a 45 degree angle through
    the center of the pad contact. Having a long tail moves that point to before the caliper arm and
    reduces its tendency to twist and wear the pad with toe-in.

    Use symmetrical pads for best results and when using asymmetrical pads, the long end goes
    to the rear.

    Jobst Brandt [email protected] Palo Alto CA
     
  5. A Muzi

    A Muzi Guest

    "Frank DiDomenico" <[email protected]> wrote in message news:BA96BC30.2C493%[email protected]...
    > With asymmetrical brake pads does the longer end of the pad extend toward the front or to the
    > rear of the bike? A diagram on page 32-16 of Barnett's Manual shows them extending to the
    > front, but I think this is wrong. Which way?

    They work not only fine but often better if you cut them down to a normal symmetric size! The
    manufacturer recommends long side behind the brake, short to the front, as you noted. BTW shorter
    pads can sometimes cure harmonic resonance in brakes. AFAIK, longer is not better in any way except
    to pander to the mistaken idea that puck size matters. It's swept area!

    --
    Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971
     
  6. On Thu, 13 Mar 2003, A Muzi wrote:

    > The manufacturer recommends long side behind the brake, short to the front, as you noted.

    Here is a way to easily make up the rule, in case you forget.

    The rim is pushing the pad diagonally acting all along the contact surface. You obviously want the
    overall force (ideally zero moment, in fact) to be centered with respect to the mounting bolt, and
    so you better have more pad to the rear.

    Sergio Pisa
     
  7. Mike S.

    Mike S. Guest

    <[email protected]> wrote in message news:[email protected]...
    > Frank DiDomenico writes:
    >
    > > With asymmetrical brake pads does the longer end of the pad extend toward the front or to the
    > > rear of the bike? A diagram on page 32-16 of Barnett's Manual shows them extending to the front,
    > > but I think this is wrong. Which way?
    >
    > The asymmetry is there to put the center of pressure in the middle of the pad, something
    > symmetrical pads do not do as the toe-in of used pads proves. That toe-in is a good feature seems
    > to have been missed by the asymmetry folks. If you look at the caliper arm as being torsionally
    > flexible, it should be apparent that they twist from brake pad forces that are at about a 45
    > degree angle through the center of the pad contact. Having a long tail moves that point to before
    > the caliper arm and reduces its tendency to twist and wear the pad with toe-in.
    >
    > Use symmetrical pads for best results and when using asymmetrical pads, the long end goes to
    > the rear.
    >
    > Jobst Brandt [email protected] Palo Alto CA

    IIRC, the Shimano V-brake manual says to set up their asym brake shoes flat against the rim. That
    way you have more brake pad hitting the rim at the same time.

    Someone actually have the Shimano manual?

    Mike
     
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