Originally Posted by
David Bierbaum
My only hesitation about carbon fiber composites is in a composite's unique failure mode of delamination, which can be impossible to detect without special equipment, yet seriously weakens a part that looks and feels perfectly good. As bicycle manufacturers become more familiar with using composites, and possibly with contributions in automated composite techniques learned by Boeing for it's 787, maybe this won't be such a problem.
The youtube video of the truck running over tubes is true, yet pointless, since it is measuring stress/strain in a way that doesn't apply to stress/strain in a bicycle frame. Also, the use of a titanium tube that hasn't yet been drawn, so that it's tube wall is still relatively thick, is a bit of a bait and switch tactic. Any bicycle with tubes able to withstand being run over by a car, are going to be insanely heavy. I'm thinking of the BSOs in the house, that are made of high-tension steel. The tube walls are nice and thick, and resistant to crushing forces that would flatten my cro-moly bicycle into a 2D artwork, but the smaller "bicycle" weighs MUCH more than my larger bicycle.
I don't know why I'm adding to the flameyness with nitpicking for which I offer no supporting evidence or documentation. I must enjoy the feeling of humiliation as my comments are mercilessly picked apart and debunked, proving my idiocy in voicing loudly opinions bathed a solution of FAIL and WRONG...
I really ought to hit the "cancel" button instead of the "Reply" button...
Why? I really don't see a lot of flaming here ... just good discussion. Including yours!
I don't feel the need to defend or attack carbon, Ti, Al and steel. They all have their advantages and disadvantages. I have a CF bike, several Al bikes and one that's a combination of CF and Al. And I used to ride steel (I don't anymore ... I live near the beach and even the best of them start to rust). I've seen stainless steel bikes too ... expensive, but kinda cool. It's also true that you can make a good bike or a crappy one from any combination of CF, Ti, Al, or steel.
I've actually written some documents directed to finding defects in CF materials in aerospace applications. Damage and failures
are harder to detect, and CF is brittle, which can lead to catastrophic failures. Obviously, I think that is a manageable risk, as I spend most of my time on a CF bike.