Bonnie- The seat post diameter is not a true indicator of the tubing specs. Between the heat induced distortion, seat lug binder slot burrs and the fact that the factory didn't actually insert the seat post supplied into the frame there can be a few tenths of mm range of the post that the shop which assembled the bike ended up using. The shop I worked at in the 1970s would use the post size that worked with out much frame prep.
>
> ----- Original Message -----
> From: Bonnie Garner
> To: classicrendezvous@bikelist.org
> Sent: Saturday, June 26, 2010 1:42 PM
> Subject: Introduction/Peugeot PXN-10E ?
>
>
> Hello: I am new to the list, so a little about myself. I got into
> cycling seriously in 1983, but never raced, just rode recreationally.
> First bike was an OT 1984 Trek 420 that I rode untill ordering a custom
> Bruce Gordon road bike in 1987. Out of cycling for various reasons in the
> 1990's and began riding again in 2001. Currently have a OT Kogswell PR, a
> OT Centurion Pro Tour, and recently acquired an on-topic Peugeot PXN10-E
> frame. I have been a lurker on this list for 3-4 years and am excited
> about now being a member. Thanks for having me.
>
> My questions for the Peugeot experts concern the 531 tubing guages used on
> the CXF frames and the PXN bikes. This frame takes a 26.4 seat post
> indicating a frame construced w. Reynolds metric tubing. The bottom
> bracket has the following: A serial number? that reads "1344936" and the
> model number of "PXN10E 60". The frame also has Super Competition on it.
> The Reynolds sticker is in French w/ 531 diagonaly printed in green on the
> decal and indicates that all main tubes and forks were built w/ 531 DB
> tubing. The 531 decal is placed high on the down tube. In my research, I
> have uncovered perhaps conflicting information concerning the GUAGE of
> tubing used. On Miami Jim's excellent site, he shows this 531DB decal in
> English and a chart indicating the top tube was 1/.7/1 guage. On a
> Gazelle web site, an E-Mail from Reynolds corp. states that in 1981 the
> 531DB tubing was re-named as 531C, 531ST and 531DS. This e-mail states
> that the old 531DB was essentially the new 531C.
> This latter reference makes sense to me because first, the PXN-10 frame is
> a relatively light racing frame and the 531ST was the touring spec that I
> have seen indicating 1/.7/1 top tubes. Finally, I have read many a
> comment in the archives of this list by owners of primarily PX-10's that
> the ride on these and similar Peugeots are superb and crediting this
> possibly to the metric sized tubing.
>
> Sorry for the long post, but any help with these questions and any other
> comments is greatly appreciated.
>
> Rick Hill
> Ripley, MS USA
>
> _______________________________________________
Andrew R Stewart
Rochester, NY