The quote I made concerning Terry and the Reynolds 531cs is based upon what was on my bike and on a Trek 760 here with photos to prove it; see:
http://www.bikeforums.net/showthread...ighlight=531cs When I bought my bike in the summer of 84 I bought it as a frame and fork, there use to be a reynolds 531 sticker on the fork as is pictured in the above photo, Terry claims that 531cs was only the main tubes and not the stays and fork which in the case of the forks is untrue...some of the time, it is possible that Trek may had spec'd 501 for the forks but later changed to 531. It's not unusual for manufactures to change specs during production and wouldn't reflect those changes in the catalog since that would mean reprinting a new catalog any time that happened, so it's also possible that my 660 could have been issued that way even as complete bike since I got the bike in the late summer of 84, or it was a quirk when buying just the frame and fork.
If by chance Schwinn got a better deal to use Duopar on the rear derailleur and Suntour for the front for example doesn't mean the parts are second rate. Somehow you think I'm attacking your bike by mentioning that a bike company submitted contract bids for the best price on various parts from various manufactures, this sort of stuff goes on all day long in all industries! I'm in no way attacking your bike or insinuating your bike is made inferior due to price bids, I'm sorry if you thought I meant that it's just the way manufacturing business is ran.
I once had found a list of custom builders who did use the 531cs, I see you found that, I did mention a few select custom builders did manage to get their hands on some 531cs tubing was from everything I could find out 531cs was made to order specifically for Trek, anyone else using it simply got surplus that Trek didn't use...again, just to repeat myself, that is what I have come to understand about 531cs over the years, if you can find where 531cs was made before Trek started using it and thus was not made exclusively for Trek please share it.