weinmann semi automatic brakes -- what is it?

Discussion in 'Cycling Equipment' started by geos, Apr 13, 2006.

  1. Peter Cole

    Peter Cole Guest

    Jasper Janssen wrote:
    > On 15 Apr 2006 00:08:55 GMT, [email protected] wrote:
    >
    >> I think you are confusing the issues. Drum brakes have plenty of
    >> stopping power and good stopping distance. What they don't have is
    >> control that is essential in operating them at the transition between
    >> tracking and skidding, especially in curves and on wet roads. I don't
    >> contend that the Campagnolo Delta brake did not stop the bicycle, but
    >> that its varying mechanical advantage made it difficult to control.

    >
    > Doesn't a brake that routinely skids the wheels have bad stopping power?
    > If your wheels are skidding you're not stopping with anywhere near the
    > theoretical maximum.. why ABS was invented.
    >


    A front brake, being the only important brake for rapid stopping, will
    usually cause a near-instantaneous crash if it locks the front wheel. On
    dry roads, you have a warning when the rear wheel lifts, on wet roads or
    loose surfaces you often don't. Under slippery conditions, it's critical
    to be able to control the amount of braking force precisely, a
    non-linear response makes that harder. This isn't noticed too often when
    riding on pavement, since the coefficient of friction is pretty good,
    but riding off-road in sand, gravel, mud or leaf litter is much more
    challenging. Predictable brakes are much more important than gross
    stopping power.
     


  2. On 15 Apr 2006 20:12:36 GMT, Helmut Springer <[email protected]>
    wrote:
    >G.T. <[email protected]> wrote:
    >> Not stopping power but stopping distance. And during a similar
    >> discussion on rec.photo.digital.slr-systems, where it was quite
    >> off-topic, I found several documents where the goal was to reduce
    >> stopping distance during panic stops.

    >
    >References? Bosch happens to have driven that for cars, and their
    >goal was control...


    Well, sure, you can push much more drug^Wsafety features by claiming that
    they prevent you from skidding into a ravine or 18-wheeler than you can by
    claiming they'll make you stop slightly faster.

    Thing is, you get a much larger decelerating force by braking until
    just-before the wheel starts skidding than when it actually is skidding,
    because friction coefficient for moving materials (the skidding tyre
    versus the road) is much smaller than that for stationary materials (the
    rolling tyre versus the road). Which is also why the front wheels stop
    being able to make sure the car goes straight, or anywhere in particular,
    in a skid.

    Therefore, you either have to make sure you don't go over that edge
    manually, back the brake off manually when it's gone over, or use ABS, to
    get the best stopping distance (and if smallest stopping distance and
    largest stopping power aren't the same thing in your book, that's a mighty
    weird definition). Control and stopping power are directly related in the
    try-not-to-skid part of automotive techniques.

    Jasper
     
  3. Jasper Janssen <[email protected]> wrote:
    > Therefore, you either have to make sure you don't go over that
    > edge manually, back the brake off manually when it's gone over, or
    > use ABS, to get the best stopping distance (and if smallest
    > stopping distance and largest stopping power aren't the same thing
    > in your book, that's a mighty weird definition).


    Interestingly skilled drivers achieve shorter stopping distances
    without ABS. Most drivers are not that skilled.

    Still the driver to deploy ABS was control.

    That does allow the average driver to fully hit the brakes and still
    have control thus coming to shorter stopping distances than not
    braking powerful enough fearing to lose control...

    --
    MfG/Best regards
    helmut springer
     
  4. On 16 Apr 2006 09:39:51 GMT, Helmut Springer <[email protected]>
    wrote:
    >Jasper Janssen <[email protected]> wrote:
    >> Therefore, you either have to make sure you don't go over that
    >> edge manually, back the brake off manually when it's gone over, or
    >> use ABS, to get the best stopping distance (and if smallest
    >> stopping distance and largest stopping power aren't the same thing
    >> in your book, that's a mighty weird definition).

    >
    >Interestingly skilled drivers achieve shorter stopping distances
    >without ABS. Most drivers are not that skilled.


    In controlled circumstances where the road surface is fairly regular and
    when the driver in question has experimented with deliberately going into
    skids on that surface, and thus knows exactly how hard he can brake
    without going into one, yes. It's not that most drivers are unskilled,
    it's just that they don't have any experience with going into skids,
    because it's not taught and it's not advisable to try it on public roads.

    >Still the driver to deploy ABS was control.


    Not on this side of the ocean, it was always about shorter stopping
    distances.

    >That does allow the average driver to fully hit the brakes and still
    >have control thus coming to shorter stopping distances than not
    >braking powerful enough fearing to lose control...


    Yep.


    Jasper
     
  5. Jasper Janssen <[email protected]> wrote:
    >>Still the driver to deploy ABS was control.

    >
    > Not on this side of the ocean, it was always about shorter stopping
    > distances.


    Which is where?

    --
    MfG/Best regards
    helmut springer
     
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