What size clamp is used with a frame that has a 31.6 post.

You'll probably need a 35mm clamp, but it's best to measure. In most cases it's the same clamp diameter as your front derailleur.

If... nm still works in this forum!?

You'll probably need a 35mm clamp, but it's best to measure. In most cases it's the same clamp diameter as your front derailleur.

Just FWIW, on some frames it is not the same as the Front mech clamp, which surprised me when I found this out. This can be due to the fact of butted or tapered tubing on a frame.

Trevor!

What size clamp is used with a frame that has a 31.6 post.

I use a 31.6 Tune seatpost and my Extralite clamp size is 34.9mm both are for sale btw

...Salsa in particular, use 35.0mm for their binder.

...all important "most" in there. There is always the exception.