Short version of the question is this:
Does anybody have access to a pre-war Peugeot racing bike and could they document the frame geometry of it?
http://www.peugeotshow.com/
The longer version of the question is this:
I'm interested in understanding more about when the classic road racing geometry began to emerge and separate itself away from the longer wheelbased designs. Many 50 vintage British bikes (Mercian, Raleigh) used 73 or 72 parallel angles, longer stays in the 6.0cm range and longer stays.
This longer, more relaxed geometry appears to have persisted into the 70s being sold as a light tourer, amateur racer, semi-pro racer or it would seem among production Gitane Tour de Frances.
In the write up on the Raleigh International, the author (Ray Chong or Sheldon Brown?) states:
"While the Professional was patterned after the popular Italianate style popular in the early '70s, the International harkend back to an earlier ear. The International frame was built for comfort, lightness and verastility, while the Professional was built for stiffness and maneuverability. The Internationals had very generous tire clearanbce (hence the need for the long-reach Weinmann calipers) and relaxed angles."
See: http://www.sheldonbrown.com/
The 1936 Peugeot's I posted a link to are interesting to me in that they *appear* to both have the longer, more relaxed geometry.
By 1951, it appears that Peugeot was discriminating between
"sport", "course" (racing) and "course professional" (pro racing).
http://www.peugeotshow.com/
Again, in 1963, Peugeot makes the distinction between the
amateur racer and the professional racer and again, it would
be interesting to know if the professional was starting to
tighten up and steepen. That rear triangle looks shorter to
my eyes.
See: http://www.peugeotshow.com/
In like manner, the Raleigh Professional looks to be a steeper
shorter layout by 1969.
http://www.sheldonbrown.com/
The real question here is where did the short wheelbase racing geometry start and when did it find it's way into the mainstream in both British and French production bikes?
NOTE: A Gitane collector submitted specs for the 70s vintage TdFs that are definitely pretty stretched out: 72.5 degree parallel, 5.5cm of rake and 45cm stays.
-Dave Mann, Boston, MA
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THE BIKE GEOMETRY PROJECT
A community effort to document and compare bike geometries
http://home.comcast.net/