Originally Posted by
Bob Ross
But "classic bi-directional weave" is (was) almost always used as a cosmetic layer only
I don't believe that is true, but I'm not by any means a composites expert. There are properties of both unidirectional and woven bi-directional carbon that are beneficial to the combined structure. There may well be more emphasis on unidirectional layers in a high-end modern bike frame, but woven carbon is not merely for cosmetic use.