Originally Posted by
Insidious C.
An unidentified 70s vintage French frame has 531 butted main tubes (they are marked as such). The head tube has a visible seam. But the stays have neither an obvious seam nor markings. Are there other clues that would identify the stay tubes?
I don't think that head tubes were ever in the 531 set (someone correct me if I'm wrong). At the very least, the 531 decal that says "butted tubes forks and stays" doesn't guarantee it. If your decal doesn't mention the stays, I'd guess that they aren't. If you look up from inside the bottom bracket with a flashlight you should be able to tell if there's a seam or not, if you haven't already.
But then, as they say, pics or it didn't happen!
EDIT - I just thought of something. I can almost always tell if the stays are "higher quality" when cold setting them. The lower grade ones yield fairly easily, higher grade take more effort. My arms are fairly well calibrated ;-)