Originally Posted by
cyclotoine
I have a bike from the very early 1970s (presumed built in about 71/72) made of reynold 531 butted tubes frame, fork and stays. The bike is a 62cm and it appears that a 27.0mm seatpost is the right size. I thought all butted 531 tubesets would be 27.2mm, but it appears I am wrong. I guess reynolds came with different butting configurations for different applications? Sorta like columbus SP vs. SL...
Any thoughts? I'm pretty damn sure on this as a 27.0 post slides in nicely but is snug with no rocking or play even with the binder undone, a 27.2 will not go in under any circumstance.
Reynolds 531 butted could have been found in a number of seattube IDs. from 27.2 down to 26.4 and prolly even smaller. I remember my 71 PX10 was 26.4 and my Limongi (76) was Reynolds Superlight 531DB and also is 26.4. 26.8 is very common.
And 27.0 was as common as 27.2 (maybe more...) for Reynolds built in the 70s and even early 80's.
I'm sure there's a source for listing some of the common bikes and seattube sizes...
use what fits best