Originally Posted by
nlerner
1970s Raleigh also tend to have relatively short top tubes, no matter the seat tube size. I have a Grand Sports with a 62cm seat tube and a 57cm top tube (c-c),
Reynolds apparently made most of their sets of 531 with 57cm top tubes. Many, but not all, 531 bikes from the 70s have a 57cm top tube.
I've owned two Japanese bikes from the 80s, a Fuji and a Shogun, with 56cm top tubes. Based on what I've read on this forum, it seems like 80s Japanese bikes (including the Nishiki mentioned) tend to have shorter top tubes. I have no idea if this is true, but there seems to be anecdotal evidence.