is there a standard 531 seat tube size?
My 74 Ellis-Briggs is what I'm trying to figure out a post for. It's full 531, so I was hoping there was a standard seat tube size for 531, or at least that time period. The guy I bought the frame-set from said it was 27.2, but that doesn't seem to be the case. A 26.8 post I have goes in, but seems like it May be a little too small. Is there an even 27 that I need? Being a newbie, I could well be mistaken and 26.8 might be the proper size, so once again I turn to you guys who always know more than I.