Originally Posted by
icemilkcoffee
Is that really the case? A seatpost only needs to be strong in the front-back direction. Indeed Thompson seatposts made use of this principle and made the internal thickness thicker in the front and back sides and thinner on the left and right. An oval seatpost is actually stronger than a round seatpost in the front-back direction.
Now if you were arguing that the Giant D-Fuse seatpost is weaker then I would agree with you. Their D shape definitely weakens the backside of the post.
Good point. Does "strong" = "rigid"? The D-shaped seatpost is intended to be less rigid in one particular direction, but that doesn't mean it's prone to failure, with is another way of thinking of weakness vs strenght.,h