Originally Posted by
Road Fan
For some of their stuff Nitto is very clear about the measurement standard, and for others not. It's an issue for stems, as well.
Holding the seatpost at the 70-ish angle from the vertical, I tend to measure from the centerline of the shaft that goes inside the seat tube, to the center point of the seat rail clamp.
I don't care, really, if my measurement matches Nitto's. I measure so that I can compare a given post with another regardless of manufacturer, to figure out if I should or could substitute one for the other. I don't care about "whether Nitto is wrong."
So where did you get custom seatposts?
TiCycles. They make stems, seatposts and a lot of other one-off stuff on request. Also a wide range of repairs on steel and ti. Very good; not cheap. I like them because I can go to them with a very specific idea and they will build it, not say "we only do it this way" or "you want this". (You will get questioned "why" and may well have it pointed out that if you do "that", "this will happen and you might want to take this other approach..)