I have had this conversation about AL vs. steel frames with a metals expert, he told me his title, but I forgot it, and a frame builder. The metals guy was a 150 lber, and he said he had even raced on a steel bike b/c the catastrophic failure of Al is sudden, unlike steel which you can see happening, or it will bend more or whatever...
I don't like to belive everything I hear, but this did scare me, weighing 240.
It is strange also that steel is flexier, and heavier for a tall person bike, which most likely is going to have longer tubes, and that tall person, built the same as a shorter person will weigh more. Where does this become off balance? should a tall person have to ride a super heavy bike, jsut cuz they're tall?
Mostly it is just fascinating to me that people can construct these bicycles which are so delicate and strong at the same time.
But I am patiently (read impatiently) awaiting my custom bike with steel frame.