Originally Posted by
DiabloScott
Yeah, I think that's pretty much accepted as fact. Although there's a range of dent-resistance based on wall thickness, aluminum tubes are generally thinner than other metal tubes used for bikes, and some aluminum tubes are thinner than other aluminum tubes.. .....
I'm calling "B.S." on this over-generalization. While it may be true that 'fat tube' aluminum frames like Cannondales or Kleins might be thinner than steel (not certain, I've never cut an aluminum frame apart), that is only because of the larger tubing diameter. If you take the tubing from one of those Trek bonded aluminum frames, however, you would be wrong (probably).
To make a long story short, all aluminum has a higher ductility modulus than any steel does. However, since the strength modulus is roughly 1/3 that of steel, you need roughly 3x the thickness at any given point to have the same strength. If this is achieved by enlarging the tubing diameter, then, yeah, it's easier to dent, guaranteed.
And CF does not 'dent' at all, it will eventually fracture, though.