ping sheldon brown - sugg. for frame torsional stiffness test

Discussion in 'rec.bicycles.soc archive' started by Spacey Spade, Apr 26, 2003.

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  1. Spacey Spade

    Spacey Spade Guest

    Dear Sheldon Brown,

    Thank you so much for your web pages devoted to cycling.

    I would very much like to see a torsional test on bicycle frames where the frame is held by the
    wheel axles, and the deflection measurements are at the bottom bracket due to loads on the bottom
    bracket. This would be a simple simulation for in-saddle hammering (when arms are not used). Is
    there some test results published already?

    For the test you could use a 1" steel bar in the steerer as in a previous test of yours, making sure
    to afix the bar on the axis where the front axle would be (and not allowing it to rotate there, but
    allowing rotation in the steerer tube... either that or use the same forks on all frames hehe!). You
    could even put weights on the saddle and on the handlebars to make it even more lifelike.

    Having owned a Schwinn Premis, now a Cannondale, I really appreciate the torsional stiffness from
    the Cannondale. On the Schwinn I used to look down and see the bottom bracket swinging from side to
    side under load (and the chainring would rub the front derailleur to the same tune if I didn't have
    it adjusted right).

    Regards,

    Spacey BSME
     
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  2. Mitch Haley

    Mitch Haley Guest

    Spacey Spade wrote:
    >
    > I would very much like to see a torsional test on bicycle frames where the frame is held by the
    > wheel axles, and the deflection measurements are at the bottom bracket due to loads on the bottom
    > bracket.

    Then you would like to see Bicycling magazine's frame test jig, AKA "the tarantula". Back in the
    1980's, when Gary Klein and then Canondale were becoming popular, Bicycling published BB deflection
    for all bikes and frames they tested. Now they assume the readers are illiterate, so bike tests have
    lots of pictures, few words, and fewer numbers. You might get more info on rec.bicycles.tech, this
    topic seems to be more suited for that group. Mitch.
     
  3. Ken

    Ken Guest

    Mitch Haley <[email protected]> wrote in news:[email protected]:
    > Then you would like to see Bicycling magazine's frame test jig, AKA "the tarantula". Back in the
    > 1980's, when Gary Klein and then Canondale were becoming popular, Bicycling published BB
    > deflection for all bikes and frames they tested.

    Unfortunately Bicycling Magazine no longer tests bicycles. Now days they only publish puff pieces or
    thinly veiled press releases. They don't want to piss off their advertisers with any level of
    criticism.
     
  4. Spacey Spade

    Spacey Spade Guest

    Ken <[email protected]> wrote in message news:<[email protected]>...
    > Mitch Haley <[email protected]> wrote in news:[email protected]:
    > > Then you would like to see Bicycling magazine's frame test jig, AKA "the tarantula". Back in the
    > > 1980's, when Gary Klein and then Canondale were becoming popular, Bicycling published BB
    > > deflection for all bikes and frames they tested.
    >
    > Unfortunately Bicycling Magazine no longer tests bicycles. Now days they only publish puff pieces
    > or thinly veiled press releases. They don't want to piss off their advertisers with any level of
    > criticism.

    Moved to rec.bicycles.tech, thank you!
     
  5. Hasn't everything?

    I can no longer find the line between the media and the ads. Remember GW Bush's heroic post 9-11 (go
    out and buy stuff - go on vacation) speech?

    All Herald the Brave New World.

    "Ken" <[email protected]> wrote in message news:[email protected]...
    > Mitch Haley <[email protected]> wrote in news:[email protected]:
    > > Then you would like to see Bicycling magazine's frame test jig, AKA "the tarantula". Back in the
    > > 1980's, when Gary Klein and then Canondale were becoming popular, Bicycling published BB
    > > deflection for all bikes and frames they tested.
    >
    > Unfortunately Bicycling Magazine no longer tests bicycles. Now days they
    only
    > publish puff pieces or thinly veiled press releases. They don't want to
    piss
    > off their advertisers with any level of criticism.
     
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