Put on the Thomson?
 

Question: Assuming a saddle can be placed in the exact same fore-aft position – using the rails – is there any particular pro or con for using a set-back post vs a zero setback post? Everything on my bike is carbon, but my son gave me a Thomson Elite which looks soooooooooo good. My current post is a middle of the road carbon post with a 5mm setback, so I’m certain the Thomson could be put in the same position. As a biker who is not going to be placing a great deal of strain on any bike part, I know I wouldn’t see any difference in performance. Just hate to let the Thomson sit in my gear chest. Also, would inserting a metal post into a carbon tube be of any concern?

Same answers as the other place. Do it.

Pro- would be if it makes it a better fit. Con- would be if it makes the fit worse.

Sounds like the Thompson would be a great upgrade. I personally prefer an aluminum seatpost over a carbon.

remember that once you grease up your AL post and install it, it would be hard to clean out the grease to go back to carbon.

check out my thread from this morning concerning set-back and 0 setback and the problem I am having on the Road cycling forum

If your current seatpost has a clamp that is not centered on the shaft of the seatpost (think Kalloy for a good example), get the setback.

If your current seatpost has a clamp centered over the shaft of the seatpost, then get the non-setback.

There you go!