OK, so the seat post is 27.2
The OD of the steel seat tube is 30mm on the nose
^^ “Seatpost is 27.2mm you need a 31.8mm seat collar ” this was the advise I was taking when I ordered, Cant remember where I read it previously.
If I fully tighten these ones I have with the 34 on them they are loose on the 30mm tube.
Guess I should try the next size down or something.
Why don’t they just state this clamp is for seat-tubes between Xmm and Ymm that would make life simpler :)