also remember that any material is a isometric material, meaning that as you draw the metal out, it will have very similar thickness all the way around the tube, meaning it's stiff side to side (stiff when climbing) and stiff up-down (harsh ride). This is true for aluminium, less true for steel because it's more flexible. but with carbon, you can have stiff side to side but pliable up down. Merely saying weight is not enough of a quantifier.