Originally Posted by
Andrew R Stewart
Jeeze... Frame materials are not infinitely stiff. Any tube can be compressed and rebound if done within it's "strength" limit. We use to do this with lightweight steel tubes decades ago and can still do this with carbon. The question, or trick, is to use enough pressure for some deflection but not deformation. One way to see the deflection is to watch the light reflection around one's finger/thumb. As the tube's surface deflects the light's reflection distorts. When the pressure is released the light reflection shows no distortion so no surface deformation remains.
One could use a controlled clamping device to really test this, oh that's right a repair stand jaw is such. measure the tube diameter at 90* to the clamp's compression before, during and after and report back.
there seems to be a miss guided, "on a pedestal", impression (yes, a pun that's fitting) of what constitutes tube damage and what happened before said damage is real. Andy
I think I we can agreee on your statements. However, just leaning on a top tube shouldn’t invoke a ‘materials testing lab’ conversation. I’m sure he didn’t damage it; I just wouldn't ride a frame with main tubes that flexible.
jeez, if it visibly moves when casually leaned on, I’d rather not imagine what it might be doing as I’m doing sprint intervals or riding a rough gravel road.
But alas, my guess is it didn’t really flex, just felt like it.