Originally Posted by
flyboy2160
I never said all frames have to be triangulated. just that it's the most weight and stiffness efficient design.
If a designer wants to choose to emphasize something else, that's a free choice. Do you really think I don't know about the single top tube designs? Their designers have chosen that most likely for cost and simplicity over weight - a valid decision. The bikes with the fold in the top tube would have a more complicated fold mechanism alignment issue if the fold line extended down to a second pivot in a lower front tube.
...But the Castro is just an incompetently designed mess intended to look "kool." They had the tubes and the space to make a diamond, but instead chose an open X design. I've never, ever seen an open X used as a piece of real structure and you haven't defended it from an engineering point of view - you ducked the issue. And it's not me being pompous, it's Mother Nature saying so. I'll say to you what an aerospace colleague of mine once said about know-nothing managers making technically incompetent decisions: you may choose to ignore the laws of physics, but the laws of physics never ignore you. Enjoy your ignorance.
On one hand, you never said that all frames have to be triangulated, that a designer is certainly free to choose something else, that you know about single top tube designs, that their designers most likely chose the design for valid reasons, and that such a design is a valid design decision.
Then you call the Castro an incompetently designed mess for what is basically a braced single top tube design. Do you know of Castro bikes which have failed? Why do you assume that the tubing diameter and thickness do not conform with best engineering practice, where single top tube design is concerned? And if you don't know the spec for the tubing, why do you assume that the builder is ignoring the laws of physics?