Curved Seat-Stays and Vibration/Shock absorption

Discussion in 'Cycling Equipment' started by Alpine Rider, Mar 14, 2003.

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  1. Alpine Rider

    Alpine Rider Guest

    I'm wondering if curvy seat-stays really absorb any more road vibration versus straight seat stays
    of the same material?

    A few bike makers claim they do whiles others of course say there is no difference. I know the main
    triangle doesn't flex much vertically but with those curvy seat stays like on litespeeds, sevens,
    merlins do they bend a little more since the curve exposes them to more bending forces and allow a
    slightly smoother ride?

    Thanks

    --
    Using M2, Opera's revolutionary e-mail client: http://www.opera.com/m2/
     
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  2. Mike S.

    Mike S. Guest

    "Alpine Rider" <[email protected]> wrote in message
    news:eek:[email protected]...
    > I'm wondering if curvy seat-stays really absorb any more road vibration versus straight seat stays
    > of the same material?
    >
    > A few bike makers claim they do whiles others of course say there is no difference. I know the
    > main triangle doesn't flex much vertically but
    with
    > those curvy seat stays like on litespeeds, sevens, merlins do they bend a little more since the
    > curve exposes them to more bending forces and allow
    a
    > slightly smoother ride?
    >
    > Thanks
    >

    Oh, boy, this should be fun...

    There's a discussion about frame materials and ride quality on rec.bicycles.misc right now that is
    pretty much about this same question. Go look under "opinions on aluminum frames."

    The engineers are at it again...

    Mike
     
  3. Alpine Rider

    Alpine Rider Guest

    Thanks,

    Actually I just saw a two year discussion that answered my question on google groups. I should have
    searched more carefully before. It looks like this topic starts a holy war sometimes.

    Sorry about the post if anyone is interested in the old discussion its at:

    http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=utf-8&threadm=3AA6CD70
    .8254F587%40prodigy.net&rnum=4&prev=/groups%3Fq%3Dseat%2Bstay%2Bshock%2Babso
    rption%26hl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3Dutf-8%26selm%3D3AA6CD70.8254F58
    7%2540prodigy.net%26rnum%3D4 "Mike S." <[email protected]> wrote in message
    news:6%[email protected]...
    > "Alpine Rider" <[email protected]> wrote in message
    > news:eek:[email protected]...
    > > I'm wondering if curvy seat-stays really absorb any more road vibration versus straight seat
    > > stays of the same material?
    > >
    > > A few bike makers claim they do whiles others of course say there is no difference. I know the
    > > main triangle doesn't flex much vertically but
    > with
    > > those curvy seat stays like on litespeeds, sevens, merlins do they bend
    a
    > > little more since the curve exposes them to more bending forces and
    allow
    > a
    > > slightly smoother ride?
    > >
    > > Thanks
    > >
    >
    >
    >
    > Oh, boy, this should be fun...
    >
    > There's a discussion about frame materials and ride quality on rec.bicycles.misc right now that is
    > pretty much about this same question. Go look under "opinions on aluminum frames."
    >
    > The engineers are at it again...
    >
    > Mike
     
  4. Bruce

    Bruce Guest

    Alpine Rider wrote:
    > Thanks,
    >
    > Actually I just saw a two year discussion that answered my question on google groups. I should
    > have searched more carefully before. It looks like this topic starts a holy war sometimes.

    Anybody who thinks stays make good springs aint too bright. The flex is utterly insignificant
    compared to the tires.

    But then, some people believe in homeopathy, alien autopsies and a just world.
     
  5. Bluto

    Bluto Guest

    "Mike S." <[email protected]> wrote:

    > There's a discussion about frame materials and ride quality on rec.bicycles.misc right now that is
    > pretty much about this same question. Go look under "opinions on aluminum frames."
    >
    > The engineers are at it again...

    Say, you're that guy who can feel the difference between a steel bridge and a concrete one just by
    walking on it, aren't you?

    Chalo Colina

    Ti bridges with carbon fiber stays are supple, yet responsive....
     
  6. Mark Hickey

    Mark Hickey Guest

    Alpine Rider <[email protected]> wrote:

    >I'm wondering if curvy seat-stays really absorb any more road vibration versus straight seat stays
    >of the same material?
    >
    >A few bike makers claim they do whiles others of course say there is no difference. I know the main
    >triangle doesn't flex much vertically but with those curvy seat stays like on litespeeds, sevens,
    >merlins do they bend a little more since the curve exposes them to more bending forces and allow a
    >slightly smoother ride?

    Nope. It's aesthetics only (well, that and perhaps a bit more heel clearance). I sell frames with
    both straight and curved stays, so I have no dog in this hunt (though I get more money for the
    curved stay model, so perhaps I should just shut up?). ;-)

    Mark Hickey Habanero Cycles http://www.habcycles.com Home of the $695 ti frame
     
  7. Mark Hickey

    Mark Hickey Guest

    [email protected] (Bluto) wrote:

    >Say, you're that guy who can feel the difference between a steel bridge and a concrete one just by
    >walking on it, aren't you?

    I've heard you can tell (the steel bridge groans under your weight, while the concrete bridge just
    kind of crackles...). ;-)

    Mark "really glad I'm average size" Hickey Habanero Cycles http://www.habcycles.com Home of the
    $695 ti frame
     
  8. On Fri, 14 Mar 2003 20:14:38 -0500, Mike Latondresse wrote:

    > Mark Hickey <[email protected]> wrote in news:[email protected]:
    >
    >
    >> Nope. It's aesthetics only (well, that and perhaps a bit more heel clearance).
    >
    > Mark don't they curve down not up...I can't remember

    In and out, for the chain stays. I have one of these, and my heel does not hit the stays, for what
    that is worth.

    But the modern curvy stays are nothing. Go find a picture of an old Hetchins. Aside from the
    beautiful lugwork, their most apparent feature are the seriously curved stays. The seat stays start
    out with an angle that would place them several inches ahead of the dropout, then curve back to it.
    The seat stays curve up, I think, giving the appearance of some sort of suspension component. I
    don't believe it worked -- if it did the rear brake wouldn't -- but it was striking.

    --

    David L. Johnson

    __o | A mathematician is a machine for turning coffee into theorems. _`\(,_ | -- Paul Erdos
    (_)/ (_) |
     
  9. A Muzi

    A Muzi Guest

    "Mike S." <[email protected]> wrote in message news:6%[email protected]...
    > The engineers are at it again...

    And in the other corner, the marketing department with their "optimal modulus enhanced damping
    coefficient" or whatever gobbledygook they thought of this week.

    --
    Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971
     
  10. Mike S.

    Mike S. Guest

    "Bluto" <[email protected]> wrote in message
    news:[email protected]...
    > "Mike S." <[email protected]> wrote:
    >
    > > There's a discussion about frame materials and ride quality on rec.bicycles.misc right now that
    > > is pretty much about this same
    question.
    > > Go look under "opinions on aluminum frames."
    > >
    > > The engineers are at it again...
    >
    > Say, you're that guy who can feel the difference between a steel bridge and a concrete one just by
    > walking on it, aren't you?
    >
    > Chalo Colina
    >
    >
    > Ti bridges with carbon fiber stays are supple, yet responsive....

    Now, wooden bridges I can tell by walking over. Steel and concrete hurt my feet too much.

    Hell, I'm not convinced that the s bend stays do anything but look good either, but I get very tired
    of people trying to "explain" things by testing in a lab, but not actually riding what they're
    testing on the roads. As we all know, the difference between static testing in a lab, and dynamic
    testing under actual conditions may indeed produce different data.

    In the specific tests that are run in the lab, "you" may very well be correct in your assumptions
    and conclusions. Frames do not flex vertically and wheels do flex vertically. Tires and pressures
    account for more shock absorption than frames do, but is that all of the variables?

    Riding a bike is definitely a dynamic thing. Every rotation of the crankset brings different
    stresses on the bb/frame, wheels/tires, seat/seatpost, and every other part on the bike. As the
    balance point changes, so do the stresses on all of the parts. It may not be much, but added all up,
    there's gotta be something else going on that isn't being explained adequately.

    I'm not saying I'm always right, in fact I could be wrong. But posting after me saying "yup, you're
    a dumbass." isn't going to prove anything other than someone is 1. small minded and can't accept
    criticism, or 2. refuses to think, or 3. is petty and vain and can't accept that their theories
    aren't the most important to everyone else.

    I don't have the time, money, or inclination to undertake the study that would be required to either
    prove or disprove what I'm trying to convey. I'm going to go ride one of my 8 bikes and let y'all
    think what you want to think.

    Mike
     
  11. On Fri, 14 Mar 2003 18:20:00 -0500, Bluto wrote:

    > Say, you're that guy who can feel the difference between a steel bridge and a concrete one just by
    > walking on it, aren't you?

    If you mean one of those notorious "cheese grater" steel bridges, you bet you can feel the
    difference just by walking on it...
     
  12. David L. Johnson said--- But the modern curvy stays are nothing. Go find a picture of an old
    Hetchins. Aside from the beautiful lugwork, their most apparent feature are the seriously curved
    stays. The seat stays start out with an angle that would place them several inches ahead of the
    dropout, then curve back to it. The seat stays curve up, I think, giving the appearance of some sort
    of suspension component. I don't believe it worked -- if it did the rear brake wouldn't -- but it
    was striking.

    I seem to remember the Hetchins curlystays had another commercial purpose. The race rules at
    the time prohibited large lettering showing the manufacturer of the bike so making a very
    obvious physical feature such as the curved stays was merely a way of advertising and selling
    bikes. Len Diamond
     
  13. On Sun, 16 Mar 2003 22:25:47 -0500, Kathy Hecht/Len Diamond wrote:

    > David L. Johnson said--- But the modern curvy stays are nothing. Go find a picture of an old
    > Hetchins. Aside from the beautiful lugwork, their most apparent feature are the seriously curved
    > stays. The seat stays start out with an angle that would place them several inches ahead of the
    > dropout, then curve back to it. The seat stays curve up, I think, giving the appearance of some
    > sort of suspension component. I don't believe it worked -- if it did the rear brake wouldn't --
    > but it was striking.
    >
    > I seem to remember the Hetchins curlystays had another commercial purpose. The race rules at
    > the time prohibited large lettering showing the manufacturer of the bike so making a very
    > obvious physical feature such as the curved stays was merely a way of advertising and selling
    > bikes. Len Diamond

    I had heard that, too, but mostly in reference to their lugs, which would extend half-way up the
    stays in some instances. But this rule pre-dated my memory by many years (1950s in England, I
    believe -- not my memory, the rule you referred to), and the curly stays persisted, and even got
    more pronounced.

    Also, it seems odd that only one company would use any sort of design to identify their bikes under
    those conditions. The vast majority of racing bikes from that era would be indistinguishable from
    one another without examination of subtle differences in lugs.

    I recall one Hetchins in particular, which was a high-end touring frame with extremely curled stays.
    The purported function had to have been suspension, but like I said, if it worked, the rear brake
    would either hit the spokes or the tire.

    --

    David L. Johnson

    __o | It is a scientifically proven fact that a mid life crisis can _`\(,_ | only be cured by
    something racy and Italian. Bianchis and (_)/ (_) | Colnagos are a lot cheaper than Maserattis
    and Ferraris. -- Glenn Davies
     
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