Originally Posted by
VT to CA
Well, clamping is either good or it isn't.
If a seatpost clamp adjusts easily and precisely, and holds the saddle securely, that's good.
If it doesn't, that's bad.
There are many clamp designs- one bolt, two bolt, front to back, side to side, toothed clamps, smooth clamps... the varieties are endless. There isn't one clamp design that's widely considered to be the best. It's pretty much a post by post thing...
Lots of folks swear by Thomsons. I don't really have a favorite. If the post is light and strong and holds my saddle securely in the position I want it, I'm happy.
One poorer type of clamp is on the older-style American Classic. It has a full-length lower clamp but a very short upper clamp that only contacts the rails over say half an inch, versus a full maybe 1.5 inches for the Thompson. It hasn't caused me a problem yet, but it does concentrate rail loading into a smaller length. If you slide the saddle back a long distance, the rearward bias of body weight is cantilevered behind the supports, and could cause rails to bend. OTOH, it allows loads of setback.
But if you are big and need a lot of setback, a CLB is a better design. Both allow a lot more setback than the Thompson setback post.
Another issue with clamps is metal construction. A friend loaned me a saddle on a seatpost, thinking it was just a cheap aluminum post. It turned out to be Delrin, and in NO WAY capable of holding an angle setting.
Final issue in my opinion is not to have notches that constrain the available saddle angles. The old SR LaPrade is one example of this fault, with the Campy 2-bolt and the Thompsons being good examples of a precisely adjustable seatpost.
Road Fan