if you need a seat post with serious set back, chances are your frame is too small and/or the seat tube angle too steep. is it a sub 54 cm road frame or a 15 inch or smaller hybrid? anyway, that being said, if it is either of those, ie a small frame, you'll probably never get enough set back even with a set back post. frames like those have super steep angles resulting in too forward a riding position. then only solution is a smaller wheeled bike. 700c wheels are overrated by those who use them.