Seat post size

[LOOK695]

For a frame with 31,6mm seatpost size, would a 31,4mm seatpost work?

[xcd]

I have never heard of a 31,4 mm but if so it should still be within tolerance. It will depend on how much the frame can be closed in by the clamp. If you find the post is slipping down,cut a coke can and fit it in to act as a spacer.