Greg,
Since everyone is talking about Windsor Pros and what tubing they are made from; I figured it would be a good time to mention this. I've seen Windsor pro frames made from every tubing that is common. Reynolds 531, Columbus (sl and sp), Vitus, and Faulk tubing. I distinctly remember seing one frame that had no less than THREE different tube brands in one frame! It was a combo of 531, Columbus, and Vitus. I'm sure not by design either. Just happened to be what was available at the time. There is no question in my mind that Columbus SP tubing was used in a 50cm Windsor frame. Also, don't discount the other possibility; the seat tube could be in upside down! When it comes to Windsor frames, it is a serious mistake to think that there was any genuine intergrty to their processes, there wasn't! Don't forget where they were made.
Just my opinion based on over 25 years of experience and having seen a large number of Windsors without paint in my time.
Brian Baylis
La Mesa, CA
>
> I'd be surprised to see a 50cm Windsor Pro made out of SP, but anything's possible...