It doesn't seem to work as I thought it would. Seems that most of the flex is in the post/mast and the coupling just acts a pivot.
I would somewhat disagree, judging from what I saw in a shop yesterday. The shop guy leant hard onto the seat with his elbow and the seat tube (ie. between TT and BB) deflected 3-4mm under the force. So from my observation it's definitely the frame that provides some 'extra' flex beyond what a carbon seatpost atop a conventionally jointed frame would do.
Nobody wrote:I think the only advantage of the Damone is a lighter version of inserting a bit of flex into the bike experience. When compared with the Canyon seatpost and another carbon frame, it may not even be that. It is probably slightly faster than running 25s at lower pressures, or pushing a Brooks with a steel seatpost up a hill (both of which I do) but this only matters if you are racing. If not, then there are cheaper options.
Price is important for any buyer of a new bike of course but I think the Domane is a good integrated package of speed/weight/comfort and spec level, especially around the ~$2500 (on special) price point for Ultegra. Just my opinion, of course.
Interesting point the shop guy made was that they used to sell GIANT and the Madone fits somewhere between the Defy and TCR in the speed/weight/comfort space. I've ridden a Defy (hired for a week in Europe - very nice ride) but not the Domane ... yet. Not sure exactly where that places the Domane, but I guess comparable to the Defy, although the shop guy (who rides a Domane himself now) says it is more comfortable than even the Defy, which is saying something. His comment on the initial apparent flex with the Domane is that you notice it for the first 10-15kms then forget about it as you get used to the armchair ride.
And just on the fatigue thing, I think you most notice it during and after long road rides (say 80-90+kms) or when you do several successive long days. If you are a bit older or have any back issues (or both) then endurance geo is the bees knees, irrespective of the frame material.