I guess I didn't use enough words last time. Let's try again.
There was a time when clincher bicycle rims and tires were usually the larger 27" size rather than the smaller 700C size. At that time, were sewups also 27" and not 700C? I'm curious to know if there's a period-correct way to put 27" rimmed sewup wheels on a bike that came with 27" clinchers (and not have to deal with different brake reach, etc.)
Let me observe, as someone who rides sewups in the year 2001, that at least some 700C sewup rims seem larger in diameter than 700C clincher rims - I often find myself having to adjust my brakes shoes to the very tops of their slots. I believe I recall a Campy wheelset catalogue from a few years back where they list the ISO rim size; the number for their sewup wheels was 10mm larger than for their clinchers, 632mm vs 622mm if memory serves correctly. Of course, bead seat diameter means nothing for sewups, but the numbers were there nonetheless. Perhaps because 700C sewup rims are already larger there was/is no need for a 27" sewup rim size?
Perhaps a brief overview of the history would be in order. Anyone like to try their hand at the following 4 x 4 grid:
27" 700C Clincher Sewup Clincher Sewup 50s
60s
70s
80s+
Fill in one of the following: [A]vailable but not popular [P]opular but not used by most [M]ost people used this
Steve "always learning" Freides