Originally Posted by
LesterOfPuppets
...you won't feel seatpost flex as readily as you'll feel BB area or rear triangle flex because only the latter two occur when you're out of the saddle putting the hammer down, which is when you'll be imparting the greatest lateral forces on the bike. Seated riding where the seatpost comes into play generally does not impart as much lateral force.
...
Yes - and that makes a good case for racing situations, but I think I am like most people, with my weight planted as much on my hind quarters as it is on my hands and feet.
( I think the marketeers would rather that we not make note of that.
)