Effect of stiffer seatpost on speed

Slimtim

Can this be true?

I ride a compact framed roadbike and so use a long (290mm exposed) seatpost. I have just changed from a carbon fibre post to one made of Ti.

Am I just imagining it or does the reduction in flex mean that more of my pedalling effort is converted in to forward motion?

I feel that the change of post has transformed the way the bike rides but as I've never read much discussion about the merits of different types of post materials vis-a-vis impact on the transfer of power (I have read plenty ref comfort) is the improvement just a figment of my imagination?

Any science-minded bod like to comment?

gkerr4

hmmm.

i'd have thought that the Ti one wourl actually have flexed MORE than the carbon one.

I can't see it making any difference either way - not to speed, comfort yes, but not speed.

schlepcycling

I always understood that a stiffer seatpost means less flex which in turn means less energy 'wasted' in the flex and therefore more power goes into the pedal stroke. This is presumably the same logic applied to the use of carbon chainsets, the less they flex the more power from you is applied to the pedals, the downside however can be comfort, carbon frames or other frames with lots of carbon bits can be a bit 'harsh' to ride as they transmit more of the road shock to the rider.

passout

Surely we should ditch carbon & titanium and all ride super stiff alu seatposts then? Thompsons for example.

MattBlackBigBoysBMX

I would have thought that the flex in the post would pale into insignificance compared with the flex of the seat. :idea:

John Stevenson

Matt, it depends. I have used (briefly) a carbon seatpost that was extremely flexible. You could see and feel it moving. I can't remember whether it made any difference to feelings of speed and efficiency because it scared me so much I was too worried about it breaking to think about other details!