From: BobHoveyGa@aol.com
To: classicrendezvous@bikelist.org Sent: Wednesday, March 15, 2006 10:35 AM
Subject: Re: seatpost size for PX-10?
>My guess is that there's a very good reason for the variation... the gauge
>of the tubing. There are several flavors of 531 DB tubesets that have
> >different wall thicknesses, plus there were some Peugeots that used 531
>straight gauge. Also, some PX10's may have used a single-butted seat tube
> >to save weight (butted at the bottom, the top was the same gauge as the
>middle). The outside dimension of the tube is constant, so of course the
> >thinner the tube, the larger the seatpost needed.
>I've only seen two PX-10's without paint, but it was interesting that mine
>(a smaller frame size) had a thinner gauge stamp on one of the tubes than
> >the larger bike. It led me to believe at the time that PX-10s were using
>beefier tubes in the larger sizes, but it may just have been a coincidence.
Bob, That all makes sense. I was forgetting my 3 tube 531 Raleigh Super Course takes a 26.4 mm post. How about if the seat tube was put in upside down? I'm not up on tubing thickness and butting I guess, so not sure how that effects diameter.
Pete Geurds
Douglassville, Pa