AJS914 wrote:I don't understand the theory in play here. How would moving the saddle forward 25mm, for example, make you more aero?
The basic idea is to rotate forward, TT style, to (ideally) go lower and longer at the front, which keeping an acceptable seating position in relation to the BB. As state above though, there are other considerations, not least the point made by tarmakev that further forward will normally require a higher saddle position, which is likely - other things being equal - to increase drag.
I have ridden a zero setback post for a long time and have a view that the standard "Italian fit" with large amounts of setback is heavily imbued with cycling "lore" for which there is no good rationale, but clearly what works for one doesn't necessarily work for another