Originally Posted by
Mike Mills
You mistake my perspective on this. I can make a large triangle that is stiffer than your small triangle. Stiffness doesn't necessarily have anything to do with size. In one way, larger is stiffer.
Who says stiffness is the be all and end all of bicycle design, anyway?
It is understood that the triangles would be made of the same material, differing only in the lengths of their sides. This also means the angles of the triangles would be the same.
"Why are compact frames stiffer?" - By having smaller triangles, all other variables being equal, the frame is stiffer.
"Who says stiffness is the be all and end all of bicycle design, anyway?" - Professional racers and those who aspire to be like a pro racer. People who can appreciate a bike with a quick, responsive feel. That's not the majority of bicycle riders but it is why a great deal of research time and money is spent on designing new frames and frame materials.