Originally Posted by ShinyBaldy
I believe you are incorrect in your reasoning and understanding - alum as a structure is no more durable than a carbonfibre epoxy frame. Esp when lightweight is wanted - alum tubing becomes extremely thin.
Cannondale's CAAD7 is a good example - it is an ultra light frameset made completely of alum, to sacrifice for the light weight - the warrenty is only at 2 years with aggressive riding (whereas Cannondale usually gives a lifetime warrenty).
Carbon frames are no less cushy than alum in general - alum utilizes oversized tubing - which usually results in frames that are plenty stiff, if you want comfort, go for steel.
But the comparison between alum and carbon is false - the reason why carbon isn't used more often in general applications is because it costs more to develop and research - alum is just more cost-worthy as a beater bike because it is so darn cheap to use.
Agreed.
(Steel is real!!!!! Go steel..)
anyway, stiffness is not directly material related. Several factors kick in, such as tube design/specs, frame geometry, etc.
Carbon fiber is hard, true. But it will flex to some amount, safely. That is why Bikes with carbon forks and stays will ride more comfortably than aluminum forks. But this may not always be the case, but usually true.