Chi,
My seat post, from the center of my bottom bracket to the top of the seatpost is 23.25, which is equal to 59 cm. I have a 30" inseam on my leg.






I guess it depends on the frame and the rider? I'm about 5'10" and also ride 58cm (seat-tube) frames, but have way more than an inch of seatpost "showing". More like a fist and a half of seat post to be "exact" -- these are non-sloping top-tube frames. Maybe your frame has a 58cm top-tube and more like a 60+cm seat tube?[/QUOTE]