Originally Posted by
prathmann
The same is true of every other frame material as well since bike frames in normal use will regularly be subjected to stresses beyond the fatigue failure limit. Fortunately that 'eventually' for aluminum as well as other frame materials is usually long past the point where the frame has been discarded for other reasons. So far I have personally only experienced fatigue failures on a couple of my steel frames and still have an aluminum frame that has already far outlived those in mileage.
prathman:
While I dislike the oversimplifications encountered on
the evening news and in internet chat groups, in the
interests of diversity I'll toss one out here.
Young's Modulus: Aluminum = 69 GPa, Steel = 200 GPa
source:
http://en.wikipedia.org/wiki/Young's_modulus
This, of course, makes no allowance for design modifications
with regard to the particular use of the material (e.g. larger
tube diameters, thicker tube walls, reinforcements, gussets,
etc.) nor does it allow for increased elasticity due to alloying.
So any extended debate is really beyond the scope of this
forum.
Nevertheless, as a member of the dinosaurs (or at least endangered
species) still around in Bikeworld, I make no apologies with regard
to my love of steel framed bicycles and my dismay at the continued
assault of the $3,000 carbon fiber Buck Rogers model ZX 3000.
"I grow old … I grow old …
I shall wear the bottoms of my trousers rolled."
Regards,
Mike