On Nov 16, 2009, at 10:27 AM, verktyg wrote:
> Theoretically a 1 1/8" diameter seat tube with 0.6mm wall thickness
> would take a 27.2mm seat post that would have 0.09mm per side for fit.
>
> A 0.7mm (Columbus SP)seat tube would take a 27mm seatpost.
>
It seems that a 531 .6 seat tube is thinner than a columbus .6 seat tube. A 531 .6 seat tube is usually happier with a 27.4 seat post while a Columbus .6 seat tube is happy with a 27.2 seat post. Waterford is one of the few builders to recognize this. I think this is the reason why English frames frequently have crushed seat lugs and Italian frames-for the most part-don't. Phil Brown My 2 cents in Oakland, Calif.