Is it normal for back breaks to slide and not grab tight like front brakes

Discussion in 'Cycling Equipment' started by novice, Apr 2, 2006.

  1. novice

    novice Guest

    my back brakes dont seem to bite as hard as front brakes.
     
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  2. Sorni

    Sorni Guest

    novice wrote:
    > my back brakes dont seem to bite as hard as front brakes.


    roll backwards and they will!
     
  3. Paul Hobson

    Paul Hobson Guest

    novice wrote:
    > my back brakes dont seem to bite as hard as front brakes.
    >


    when you slow down with either brake, the weight shifts forward and
    takes weight off of the rear wheel. As such, you front brake is more
    effective with proper adjustment.
    \\paul
     
  4. bfd

    bfd Guest

  5. Werehatrack

    Werehatrack Guest

    On 2 Apr 2006 23:51:40 -0700, "novice" <[email protected]> wrote:

    >my back brakes dont seem to bite as hard as front brakes.


    Yup.

    Next?
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  6. Paul Hobson

    Paul Hobson Guest

    bfd wrote:
    > You may want to read Sheldon Brown's article on braking and turning:
    > http://www.sheldonbrown.com/brakturn.html


    Here's an issue I take with this, and I'd really like y'all's feedback:

    Sheldon says that the fastest you can stop a bicycle is by applying the
    maximum force possible to the front brake. He logically reasons that at
    full front brake power, the rear wheel is about to lift off of the
    ground, at which point applying the rear brake will skid the tire or
    just do no good at all. Let's call that front braking force, F. Also,
    let's go with what Sheldon says and let the rear brake be only half as
    strong the front, 0.5F.

    But other than an outright dismissal, he doesn't address that maybe
    applying less than full force on the front would allow you to make up
    more than the difference in the rear. Hypothetically, let's say that
    maybe applying 0.7F in the front lets you still get 0.4F in the rear;
    thus, one could brake with 1.1F or 10% more force than with the front
    brake alone. Is there any data available on this that would argue on
    way or the other? Brief googling didn't turn up any hard numbers aside
    from John Forester's coaster brake data.

    --
    Paul M. Hobson
    Georgia Institute of Technology
    ..:change the f to ph to reply:.
     
  7. novice

    novice Guest

    i mean that the back tire keeps spinning when i apply back break. its
    difficult to get the back brake to stop back tire from rotating. its
    like there is grease on the back tire rims.
     
  8. Jeff Starr

    Jeff Starr Guest

    On 3 Apr 2006 15:56:26 -0700, "novice" <[email protected]> wrote:

    >i mean that the back tire keeps spinning when i apply back break. its
    >difficult to get the back brake to stop back tire from rotating. its
    >like there is grease on the back tire rims.


    Get some new brake pads. You should be able to lock up the rear and
    make it skid.

    You never answered my question, how old are you?

    Jeff
     
  9. Jeff Starr

    Jeff Starr Guest

    On Mon, 03 Apr 2006 18:43:17 -0400, Paul Hobson <[email protected]>
    wrote:

    >bfd wrote:
    >> You may want to read Sheldon Brown's article on braking and turning:
    >> http://www.sheldonbrown.com/brakturn.html

    >
    >Here's an issue I take with this, and I'd really like y'all's feedback:
    >
    >Sheldon says that the fastest you can stop a bicycle is by applying the
    >maximum force possible to the front brake. He logically reasons that at
    >full front brake power, the rear wheel is about to lift off of the
    >ground, at which point applying the rear brake will skid the tire or
    >just do no good at all. Let's call that front braking force, F. Also,
    >let's go with what Sheldon says and let the rear brake be only half as
    >strong the front, 0.5F.
    >
    >But other than an outright dismissal, he doesn't address that maybe
    >applying less than full force on the front would allow you to make up
    >more than the difference in the rear. Hypothetically, let's say that
    >maybe applying 0.7F in the front lets you still get 0.4F in the rear;
    >thus, one could brake with 1.1F or 10% more force than with the front
    >brake alone. Is there any data available on this that would argue on
    >way or the other? Brief googling didn't turn up any hard numbers aside
    >from John Forester's coaster brake data.


    Have you ever rode a motorcycle?

    Even older cars came with disc brakes on the front and drums on the
    rear. They put the better brakes where they would do the most good.
    Think about it.


    Life is Good!
    Jeff
     
  10. Paul Hobson

    Paul Hobson Guest

    Jeff Starr wrote:
    > On Mon, 03 Apr 2006 18:43:17 -0400, Paul Hobson <[email protected]>
    > wrote:
    >
    >
    >>bfd wrote:
    >>
    >>>You may want to read Sheldon Brown's article on braking and turning:
    >>>http://www.sheldonbrown.com/brakturn.html

    >>
    >>Here's an issue I take with this, and I'd really like y'all's feedback:
    >>
    >>Sheldon says that the fastest you can stop a bicycle is by applying the
    >>maximum force possible to the front brake. He logically reasons that at
    >>full front brake power, the rear wheel is about to lift off of the
    >>ground, at which point applying the rear brake will skid the tire or
    >>just do no good at all. Let's call that front braking force, F. Also,
    >>let's go with what Sheldon says and let the rear brake be only half as
    >>strong the front, 0.5F.
    >>
    >>But other than an outright dismissal, he doesn't address that maybe
    >>applying less than full force on the front would allow you to make up
    >>more than the difference in the rear. Hypothetically, let's say that
    >>maybe applying 0.7F in the front lets you still get 0.4F in the rear;
    >>thus, one could brake with 1.1F or 10% more force than with the front
    >>brake alone. Is there any data available on this that would argue on
    >>way or the other? Brief googling didn't turn up any hard numbers aside

    >
    >>from John Forester's coaster brake data.

    >
    > Have you ever rode a motorcycle?
    >
    > Even older cars came with disc brakes on the front and drums on the
    > rear. They put the better brakes where they would do the most good.
    > Think about it.


    Oh no. I think you misunderstand me. I fully understand that a front
    brake alone can stop you faster than the rear brake alone. Not in
    anyway contending that. Hell look at cars - front wheels are typically
    must dirtier than the rear. I'm just not fully convinced that the front
    brake at fully power is always more powerful than some combination of
    both brakes at less then full power (though I do see how it's possible).


    --
    Paul M. Hobson
    Georgia Institute of Technology
    ..:change the f to ph to reply:.
     
  11. novice

    novice Guest

    older than dirt
     
  12. Werehatrack

    Werehatrack Guest

    On 3 Apr 2006 15:56:26 -0700, "novice" <[email protected]> wrote:

    >i mean that the back tire keeps spinning when i apply back break. its
    >difficult to get the back brake to stop back tire from rotating. its
    >like there is grease on the back tire rims.


    That may very well be exactly what's going on. Did this start
    happening right after you oiled the chain?
    --
    Typoes are a feature, not a bug.
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  13. Werehatrack

    Werehatrack Guest

    On Tue, 04 Apr 2006 01:46:25 GMT, Werehatrack
    <[email protected]> wrote:

    >On 3 Apr 2006 15:56:26 -0700, "novice" <[email protected]> wrote:
    >
    >>i mean that the back tire keeps spinning when i apply back break. its
    >>difficult to get the back brake to stop back tire from rotating. its
    >>like there is grease on the back tire rims.

    >
    >That may very well be exactly what's going on. Did this start
    >happening right after you oiled the chain?


    And if that's not it, pull the cable out and oil it. If it's rusty,
    replace the cable and the housing; use the good housing that has the
    inner plastic liner.
    --
    Typoes are a feature, not a bug.
    Some gardening required to reply via email.
    Words processed in a facility that contains nuts.
     
  14. Jeff Starr

    Jeff Starr Guest

    On 3 Apr 2006 18:16:58 -0700, "novice" <[email protected]> wrote:

    >older than dirt


    And apparently dumber than wood;-)

    Jeff
     
  15. novice

    novice Guest

    ok, i'll scrutinize the various parts to see what is causing it not to
    grip the rim tightly.
    thanks.
     
  16. On 3 Apr 2006 22:06:38 -0700, "novice" <[email protected]> wrote:

    >ok, i'll scrutinize the various parts to see what is causing it not to
    >grip the rim tightly.


    Be sure the rim and brake surface are clean too -- if you rub your
    finger along them and they come away grimy or oily, that's the cause.

    JT

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  17. Paul Hobson wrote:
    > But other than an outright dismissal, he doesn't address that maybe
    > applying less than full force on the front would allow you to make up
    > more than the difference in the rear. Hypothetically, let's say that
    > maybe applying 0.7F in the front lets you still get 0.4F in the rear;
    > thus, one could brake with 1.1F or 10% more force than with the front
    > brake alone. Is there any data available on this that would argue on
    > way or the other? Brief googling didn't turn up any hard numbers aside
    > from John Forester's coaster brake data.


    The point that you are missing is that the rear brake shifts the weight
    to the front wheel just the same as the front brake.

    Anthony
     
  18. Quoting Paul Hobson <[email protected]>:
    >Sheldon says that the fastest you can stop a bicycle is by applying the
    >maximum force possible to the front brake. He logically reasons that at
    >full front brake power, the rear wheel is about to lift off of the
    >ground, at which point applying the rear brake will skid the tire or
    >just do no good at all.
    >But other than an outright dismissal, he doesn't address that maybe
    >applying less than full force on the front would allow you to make up
    >more than the difference in the rear.


    Because that is obviously nonsense. A given deceleration demands a given
    force, which is applied at ground level; the torque is a function of the
    perpendicular distance between the line of that force and the centre of
    gravity of the bike+rider. The torque is not changed by which brake is
    used and so the degree to which the rear wheel is lifted is not changed;
    at deceleration equal to the maximum produced by the front brake the rear
    wheel will always be completely unloaded.

    [Of course this discusses only deceleration ultimately produced by a
    reaction with the ground.]
    --
    David Damerell <[email protected]> Kill the tomato!
    Today is Second Potmos, April.
     
  19. Tim McNamara

    Tim McNamara Guest

    In article <[email protected]>,
    John Forrest Tomlinson <[email protected]> wrote:

    > On 3 Apr 2006 22:06:38 -0700, "novice" <[email protected]> wrote:
    >
    > >ok, i'll scrutinize the various parts to see what is causing it not to
    > >grip the rim tightly.

    >
    > Be sure the rim and brake surface are clean too -- if you rub your
    > finger along them and they come away grimy or oily, that's the cause.


    Can happen easily when lubing the chain, especially with a spray lube.
     
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