The fibre glass chequer post ones were 21.2 (13/16), old ripper size, because they needed a shim for a `normal' seat tube of 22.2 (3/4)
They were deffo out in 83 because a Dutch lad came over to UK and our village for the summer that year, with a spanking new Kuwi nova, which had that seat as OG.
Pretty sure the metal post ones were out at the same time, if not before.
Fibre post ones leave less residue in the fire pit!!
MM
