Especially on hardtails?
Just curius
Narrower (26.8, 27.2mm) seatposts tend to flex more, which helps seated comfort, especially at longer extension, so whats the point in so many bikes coming with 30.9, 31.6, 34.9mm or other sizes? Especially on usually stiffer aluminium frames?
And why did 25.0, 25.4 etc get ditched, surely they'd be more comfortable still?
Does the extra stiffness make a better trade off in pedalling efficiency over the loss in seatpost flex?
Or is it simply as a result of speccing larger tubes on the bike elsewhere mean that a fatter seattube is needed to weld up against and shimming the seatpost down (on new complete bikes) just isn't 'acceptable'?