Originally Posted by
RDJeff
My caliper measured the seat post at 27mm.
I think you need a digital caliper or at least a dial model that can give fractional readings.
27mm would be strange in a French frame, I'd guess it's either 26.4 or 26.6 if the seat tube is
metric 531 DB, and perhaps smaller than 26.4 (say 26.2 ) if it were plain gauge with a 0.9 wall diameter. It would be very odd if a Follis of this vintage was NOT made from metric tubing.