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Clamping on a frame tube

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  • phaedrus
    From Surly s blog: What is important is that you should never EVER clamp any tube on any frame. Ever. Clamp the seat post, turn the damn thing upside down, do
    Message 1 of 8 , Jul 3, 2008
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      From Surly's blog:

      "What is important is that you should never EVER clamp any tube on any
      frame. Ever. Clamp the seat post, turn the damn thing upside down, do
      almost anything else. But DON'T clamp a frame tube or you might find
      yourself on the waiting list for a Big Dummy frame. Again."

      I've always been a bit nervous about clamping to the seat post since
      that, in theory, torques on the down tube. It seems like the best
      place would be the down tube along the section where its got the seat
      post inside it, but this advice from surly would seem to disagree.

      Thoughts on this whole deal?

      - phaedrus
    • Dane Buson
      ... It s pretty much the conventional wisdom. For most of *my* bikes I ignore it because I have a Carradice SQR clamp on the seatpost that makes that a pain
      Message 2 of 8 , Jul 3, 2008
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        On Jul 3, phaedrus tripped the electrons lexically so:

        > >From Surly's blog:
        >
        > "What is important is that you should never EVER clamp any tube on any
        > frame. Ever. Clamp the seat post, turn the damn thing upside down, do
        > almost anything else. But DON'T clamp a frame tube or you might find
        > yourself on the waiting list for a Big Dummy frame. Again."
        >
        > I've always been a bit nervous about clamping to the seat post since
        > that, in theory, torques on the down tube. It seems like the best
        > place would be the down tube along the section where its got the seat
        > post inside it, but this advice from surly would seem to disagree.
        >
        > Thoughts on this whole deal?

        It's pretty much the conventional wisdom. For most of *my* bikes I
        ignore it because I have a Carradice SQR clamp on the seatpost that
        makes that a pain in the patoot. If I was working on someone elses bike
        I would clamp on the seatpost. I think they're also worried for the big
        dummy because with the larger lever of the longer frame you could bend a
        tube a *lot* more easily than with a conventional bike frame.

        --
        Dane Buson - Buson@...
        I develop for Linux for a living, I used to develop for DOS.
        Going from DOS to Linux is like trading a glider for an F117.
        (By entropy@..., Lawrence Foard)
      • Rusty Greer
        when i worked in a bike shop years and years ago, the issue was using the park stand clamps on the seat tube could/would crush the seat tube. there was no
        Message 3 of 8 , Jul 3, 2008
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          when i worked in a bike shop years and years ago, the issue was using
          the park stand clamps on the seat tube could/would crush the seat
          tube. there was no concern i know about bending the frame. the
          lighter the frame the more of an issue this was of course (and this
          was before carbon fiber). since then i have almost always clamped on
          the seat tube. often times, i just simply hang the bike by the seat
          and that is good enough.

          if you are very careful, you can clamp on the seat tube, but the
          thinner the seat tube the more likely it will get crimped.

          On Thu, Jul 3, 2008 at 11:04 AM, Dane Buson <Zuvembi@...> wrote:
          > On Jul 3, phaedrus tripped the electrons lexically so:
          >
          >> >From Surly's blog:
          >>
          >> "What is important is that you should never EVER clamp any tube on any
          >> frame. Ever. Clamp the seat post, turn the damn thing upside down, do
          >> almost anything else. But DON'T clamp a frame tube or you might find
          >> yourself on the waiting list for a Big Dummy frame. Again."
          >>
          >> I've always been a bit nervous about clamping to the seat post since
          >> that, in theory, torques on the down tube. It seems like the best
          >> place would be the down tube along the section where its got the seat
          >> post inside it, but this advice from surly would seem to disagree.
          >>
          >> Thoughts on this whole deal?
          >
          > It's pretty much the conventional wisdom. For most of *my* bikes I
          > ignore it because I have a Carradice SQR clamp on the seatpost that
          > makes that a pain in the patoot. If I was working on someone elses bike
          > I would clamp on the seatpost. I think they're also worried for the big
          > dummy because with the larger lever of the longer frame you could bend a
          > tube a *lot* more easily than with a conventional bike frame.
          >
          > --
          > Dane Buson - Buson@...
          > I develop for Linux for a living, I used to develop for DOS.
          > Going from DOS to Linux is like trading a glider for an F117.
          > (By entropy@..., Lawrence Foard)
          >
        • Tone@moon-shine.net
          Phaedrus, Surly is correct. You should not clamp a bike stand onto any of a bike s frame tubing. The pressure might crush or dent the tubing and you probably
          Message 4 of 8 , Jul 3, 2008
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            Phaedrus,

            Surly is correct. You should not clamp a bike stand onto any of a
            bike's frame tubing. The pressure might "crush" or dent the tubing and
            you probably would not even notice. The slight crush could weaken the
            over-all structural integrity of that tubing.

            Some bicycle frames are even designed and built so the center of the
            tubing walls are narrow, but get thicker toward the welds. Such frames
            may have frame tubing, which looks evenly thick all around, but the
            tapering of the tubing walls might be more noticeable on the inside.
            Companies will make bikes with tapering frame tubes to reduce weight
            overall. The thicker tubing walls toward the welds retains the
            necessary strength at the stress points.
            I bring this kind of frame design up because obviously a frame with
            slim-walls in the middle of its tubes would be especially susceptible
            to "crush" or side-impact damage.

            Phaedrus, there is something I would like to clarify as well, just for
            avoidance of confusion in the future. I noticed you used the
            terminology of "down tube" when referencing what should be called a
            "seat tube." The down tube on a bicycle frame is actually the tube,
            which runs from the headset (head tube) diagonally "down" to the
            bottom bracket. The top tube obviously runs at the "top" above the
            down tube from the headset to the seat tube. The seat tube stands
            relatively vertical up from the bottom bracket and is where the seat
            post slides into.

            In any case, the best place to clamp a bike stand to a bike is the
            seat post. If you see a bike shop clamp to your frame tubing, you
            might want to consider not using them or making sure to correct their
            error.
            When I was younger I had a bike on which I preferred to keep my seat
            low. Every time I brought my bike for service to my bike shop I would
            always get annoyed at them for repositioning my seat. Of course they
            did that because the bike stand clamp did not fit in the exposed space
            available on my seat post and they were doing things the right way.

            You should not be concerned about clamping to a seat post. Think of
            it... how much do you weigh? That weight constantly shifting with
            every stroke of the pedals is resting on your seat post.
            Also, when you consider the geometry of a long tail bike compared to a
            lighter standard bicycle, the center of gravity is different. On a
            long tail bicycle the horizontal center of gravity for the bike is
            actually closer to the seat tube. On a normal bike the center is more
            like the middle of the top tube or perhaps a third of the way forward
            along the top tube from the seat tube. What all of this means is that
            when a long tail bicycle is hooked up to a stand the natural middle
            balancing point for the bike is a heck of a lot closer to the seat
            post. Also, having the clamp higher up on the seat post rather than
            the middle of the seat tube means the bike's weight is lower, thus
            closer to the ground and more stable. If it was higher up it would be
            more likely to tip to one side.

            That is the physics lesson for the day kids... now go enjoy your
            Fourth of July! :)
            Ride safe,
            _TONE_
          • Jake Wilson
            ... I think they re also worried for the big ... bend a ... ~~~~Bingo!, but I gotta add....I have been riding mostly recumbent bicycles from 2001 to the
            Message 5 of 8 , Jul 3, 2008
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              --- In rootsradicals@yahoogroups.com, Dane Buson <Zuvembi@...> wrote:







              I think they're also worried for the big
              > dummy because with the larger lever of the longer frame you could
              bend a
              > tube a *lot* more easily than with a conventional bike frame.
              >






              ~~~~Bingo!, but I gotta add....I have been riding mostly recumbent
              bicycles from 2001 to the present (& the LWB is way long). I have a
              park tool co. bike stand and with a recumbent, there is usually no
              seat post to clamp onto, you have to clamp onto the frame. I have
              used my repair stand hundreds of times, maybe thousands, and never
              have I bent any frame tubes. One of my bents I leave clamped into
              the stand 24/7 as i don't have a cieling hook to hang it from, so it
              gets taken out and put back into the clamp anytime I ride it or I
              need the repair stand for another bike


              One needs to be judicious about clamping torque




              Jake
              Reddick Fla.






              >
              > On Jul 3, phaedrus tripped the electrons lexically so:
              >
              > > >From Surly's blog:
              > >
              > > "What is important is that you should never EVER clamp any tube
              on any
              > > frame. Ever. Clamp the seat post, turn the damn thing upside
              down, do
              > > almost anything else. But DON'T clamp a frame tube or you might
              find
              > > yourself on the waiting list for a Big Dummy frame. Again."
              > >
              > > I've always been a bit nervous about clamping to the seat post
              since
              > > that, in theory, torques on the down tube. It seems like the best
              > > place would be the down tube along the section where its got the
              seat
              > > post inside it, but this advice from surly would seem to disagree.
              > >
              > > Thoughts on this whole deal?
              >
              > It's pretty much the conventional wisdom. For most of *my* bikes I
              > ignore it because I have a Carradice SQR clamp on the seatpost that
              > makes that a pain in the patoot. If I was working on someone elses
              bike
              > I would clamp on the seatpost. I think they're also worried for
              the big
              > dummy because with the larger lever of the longer frame you could
              bend a
              > tube a *lot* more easily than with a conventional bike frame.
              >
              > --
              > Dane Buson - Buson@...
              > I develop for Linux for a living, I used to develop for DOS.
              > Going from DOS to Linux is like trading a glider for an F117.
              > (By entropy@..., Lawrence Foard)
              >
            • Jake Wilson
              ... and ... the ... the ... frames ... the ... inside. ... weight ... with ... susceptible ... for ... a ... tube, ... seat ... their ... seat ... would ...
              Message 6 of 8 , Jul 3, 2008
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                --- In rootsradicals@yahoogroups.com, Tone@... wrote:
                >
                > Phaedrus,
                >
                > Surly is correct. You should not clamp a bike stand onto any of a
                > bike's frame tubing. The pressure might "crush" or dent the tubing
                and
                > you probably would not even notice. The slight crush could weaken
                the
                > over-all structural integrity of that tubing.
                >
                > Some bicycle frames are even designed and built so the center of
                the
                > tubing walls are narrow, but get thicker toward the welds. Such
                frames
                > may have frame tubing, which looks evenly thick all around, but
                the
                > tapering of the tubing walls might be more noticeable on the
                inside.
                > Companies will make bikes with tapering frame tubes to reduce
                weight
                > overall. The thicker tubing walls toward the welds retains the
                > necessary strength at the stress points.
                > I bring this kind of frame design up because obviously a frame
                with
                > slim-walls in the middle of its tubes would be especially
                susceptible
                > to "crush" or side-impact damage.
                >
                > Phaedrus, there is something I would like to clarify as well, just
                for
                > avoidance of confusion in the future. I noticed you used the
                > terminology of "down tube" when referencing what should be called
                a
                > "seat tube." The down tube on a bicycle frame is actually the
                tube,
                > which runs from the headset (head tube) diagonally "down" to the
                > bottom bracket. The top tube obviously runs at the "top" above the
                > down tube from the headset to the seat tube. The seat tube stands
                > relatively vertical up from the bottom bracket and is where the
                seat
                > post slides into.
                >
                > In any case, the best place to clamp a bike stand to a bike is the
                > seat post. If you see a bike shop clamp to your frame tubing, you
                > might want to consider not using them or making sure to correct
                their
                > error.
                > When I was younger I had a bike on which I preferred to keep my
                seat
                > low. Every time I brought my bike for service to my bike shop I
                would
                > always get annoyed at them for repositioning my seat. Of course
                they
                > did that because the bike stand clamp did not fit in the exposed
                space
                > available on my seat post and they were doing things the right way.
                >
                > You should not be concerned about clamping to a seat post. Think
                of
                > it... how much do you weigh? That weight constantly shifting with
                > every stroke of the pedals is resting on your seat post.
                > Also, when you consider the geometry of a long tail bike compared
                to a
                > lighter standard bicycle, the center of gravity is different. On a
                > long tail bicycle the horizontal center of gravity for the bike is
                > actually closer to the seat tube. On a normal bike the center is
                more
                > like the middle of the top tube or perhaps a third of the way
                forward
                > along the top tube from the seat tube. What all of this means is
                that
                > when a long tail bicycle is hooked up to a stand the natural
                middle
                > balancing point for the bike is a heck of a lot closer to the seat
                > post. Also, having the clamp higher up on the seat post rather
                than
                > the middle of the seat tube means the bike's weight is lower, thus
                > closer to the ground and more stable. If it was higher up it would
                be
                > more likely to tip to one side.
                >
                > That is the physics lesson for the day kids... now go enjoy your
                > Fourth of July! :)
                > Ride safe,
                > _TONE_
                >




                ~~~~~Ha!, Good argument TONE!!!





                Jake
                Reddick Fla.
              • phaedrus
                ... Ah, my bad. Thanks for the correction, I apparently had a mental slip. As for the rest of it, thanks for the discussion - makes sense. I didn t think
                Message 7 of 8 , Jul 7, 2008
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                  > Tone >>
                  > there is something I would like to clarify as well, just for
                  > avoidance of confusion in the future. I noticed you used the
                  > terminology of "down tube" when referencing what should be called a
                  > "seat tube." The down tube on a bicycle frame is actually the tube,
                  > which runs from the headset (head tube) diagonally "down" to the
                  > bottom bracket. The top tube obviously runs at the "top" above the
                  > down tube from the headset to the seat tube. The seat tube stands
                  > relatively vertical up from the bottom bracket and is where the seat
                  > post slides into.

                  Ah, my bad. Thanks for the correction, I apparently had a mental slip.

                  As for the rest of it, thanks for the discussion - makes sense. I
                  didn't think about crimping the seat tube to the seat post. I guess
                  I'd better slide those stoker bars up or down a bit to make room for
                  the clamp.

                  - phaedrus
                • Fred
                  Just a thought... If you have a seat tube that is long enough, could you apply the clamp to the seat tube without doing any damage? ... -- The downside of a
                  Message 8 of 8 , Jul 7, 2008
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                    Just a thought...

                    If you have a seat tube that is long enough, could you apply the clamp to the seat tube without doing any damage?

                    On Mon, Jul 7, 2008 at 11:06 AM, phaedrus <rphaedrus@...> wrote:

                    > Tone >>


                    > there is something I would like to clarify as well, just for
                    > avoidance of confusion in the future. I noticed you used the
                    > terminology of "down tube" when referencing what should be called a
                    > "seat tube." The down tube on a bicycle frame is actually the tube,
                    > which runs from the headset (head tube) diagonally "down" to the
                    > bottom bracket. The top tube obviously runs at the "top" above the
                    > down tube from the headset to the seat tube. The seat tube stands
                    > relatively vertical up from the bottom bracket and is where the seat
                    > post slides into.

                    Ah, my bad. Thanks for the correction, I apparently had a mental slip.

                    As for the rest of it, thanks for the discussion - makes sense. I
                    didn't think about crimping the seat tube to the seat post. I guess
                    I'd better slide those stoker bars up or down a bit to make room for
                    the clamp.

                    - phaedrus



                    --
                    The downside of a recumbent is the upside of a hill...
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