Originally Posted by
Scarbo
My 1972 Raleigh Super Course was built out of Reynolds 531 plain gauge tubing (not double butted). The models above the Super Course in that year (Gran Sport and above) were all double butted. I suspect that the 531 butted designation would actually specify plain gauge. What kind of frame do you have?
For decades there was no gauge hint to Reynolds 531 on the transfer.
Later they use professional, and SL among other names to help indicate thickness but you still needed the "decoder ring" to know.
Add in that there were for a time more gauge options for the metric tubes and it all gets quite complicated.
Schwinn got in trouble in the 70's for the provided Reynolds 531 "double butted" transfer.
The solution was a unique transfer that helped clear up the "legal" claim. It can be identified by the Text all being of proper alignment and two green stars on either side of the 531 text.
As stated, seat tubes are single butted in the vintage era. (From time to time a frame got bade with an inverted seat tube, butted region to the top), Ooops.