Originally Posted by
hueyhoolihan
my post referred to the seatpost. as most of the thread was a discussion of the seatpost angle.
most of us can ride a bike without the use of handlebars (like a unicycle). so i'm asking what does the angle of the seatpost have to do with comfort unless the discussion is equally focused on where one grips the handlebars. which in turn is determined by the toptube length, stem length, shape of the handlebars, whim of the rider at the moment, and where the saddle is clamped on the post?
The angle of the seatpost is determined by the angle of the seat tube though, which in turn effects where your centre of gravity lies relative to the cranks which, assuming the top tube etc is the correct length, has the greatest determining effect on the comfort/feel of the ride, because it determines how much weight you're arms have to bear, has a knock on effect on trail/fork rake and chain stay length which all in turn have an effect on the way the bike handles.
The unicycle comparison is a red herring, since you're never required to lean forward onto a set of handlebars as on a bicycle. Notice when riding no hands that you still have a fair range of forward/back upper body movement, due to the cranks being set forward of the saddle - ride no hands on a bike with a 90deg seat tube angle (same as a unicycle) and you'll barely be able to move beyond the vertical without falling forward onto the handlebars.