Originally Posted by
JohnDThompson
No, Ishiwata 022 tubing has identical wall thickness as Columbus SL (0.9mm butts, 0.6mm mid-tube). Reynolds 531 came in too many configurations to make a direct comparison, but 531 Professional (aka "Special Lightweight) with 0.7mm/0.5mm tubes was slightly lighter.
Was there a single thickness specification, or at least a single double-butted specification and a single non-butted specification, for Reynolds 531 before they started putting letters on it? For instance, the 1982 Trek manual says the Reynolds 531 tubes with no letters (as opposed to 531 SL also available that year) had 8/5/8 top tubes, 10/7/10 down tubes, and 8/5 seat tubes, which would seem to align with later 531 "Special Tourist" or "Club Sport". Was this consistent with pre-lettering 531?