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snoops
He said modelled it by eye, without original parts to measure? He’s guessed the wall thickness. He’s guessed the modulus at 80-10GPa, which will be closer to 65GPa for cycle industry grade carbon. UD and woven carbon is not ‘black aluminium’. Black aluminium is 3D woven carbon (ie fibres in X, Y and Z axis), which attempts to have the same mechanical properties in all directions, unlike conventional carbon which is very anisotropic. The cycle industry is not using this. He put a 1mm clearance gap at the back. 1mm! He modelled it pretty much worst ever case scenario with the pinch bolt right at the end of the seat post. You need a longer seatpost if you need it that far out.
It’s a crap design, but in my eyes he hasn’t followed BASIC ENGINEERING either.