Originally Posted by vpiuva
Thanks, I had never seen this transfer sheet before. So the info I thought I read about 531c was really about 531cs. A few more questions for the experts. My '84 Trek 760, according to Trek brochures, was supposed to be in 531p - is that the 531 Professional? My frame's serial # dates to 1983, but with the changed '84 lugs and paint scheme, but seemingly with the '83 531c tubing - or did builders not use 531p above a particular frame size (ala Columbus with SL/P and the X series tubing) - mine's a 58cm? And one more, in the same article I referenced it had Reynolds 501 as a seamed tubing - is that correct? Thanks again.
Yes 531P was the "professional" tubeset. It was 150g lighter than 531C, so many builders would not use it on larger frames, as thee cyclist would typically be heavier and stronger. Many manufactuers also had a cross-over point where they mixed the tubesets (i.e 531C downtube and chainstays with 531P elsewhere). I'm not sure if trek used this philosphy.
Yes, 501 was seamed. However, by this time seamed tubing had come a long way and there is nothing inferior about it. It was simply a less expensive mehtod to manufacture the tubes.