Originally Posted by
Iride01
Huh? I'm not understanding what you wrote there.
However, from the perspective of when stack and reach are discussed, as in this thread, most of us will assume it's frame stack and frame reach. If it's any other kind of stack or reach then that needs to be specified.
I wrote that the fit is determined by the relative position of the butt, bottom bracket and hands.
The position of the saddle w.r.t. the bottom bracket can be adjusted by moving the seatpost in/out and moving the saddle forward/backward.
What is left is the position of the hands w.r.t. the bottom bracket, and that cat be modeled using
frame stack and
frame reach.