My understanding is that (normal) aluminium frames have to be stiff due to bending fatigue. Steel is much more forgiving (Ti is the same, iirc), and carbon fib

My understanding is that (normal) aluminium frames have to be stiff due to bending fatigue. Steel is much more forgiving (Ti is the same, iirc), and carbon fiber in a suitable matrix can handle dynamic loads above 50% of it's ultimate tensile strength.