Originally Posted by
Noonievut
Thanks for the feedback. I'm going to look into a Thomson.
Question - how do you measure seatpost setback (centre of post to centre of clamp)? It's not indicated on the post that's on my bike, but I think it's the correct amount of setback in that the clamp is in about the middle of my saddle.
That is the standard measure - center of post to center of clamp, but the real measure of maximum setback potential on a post is determined by the distance from the front of the clamp to the centerline of the post. The clamp length might be 3cm on one model and 4cm on another. The one with the shorter clamp could have the same setback value, but actually allow another 5mm of rearward movment. None of the Thomson models has as much setback as most traditional post.
One of the oldest standards places the front of the clamp close the seatpost centerline, so a 4cm long clamp would have 20mm of setback. My FSA posts have 5-12mm more setback than that.