[CR]Re: 1975 Peugeot PR10 Geometry

Example: Framebuilding
Date: Thu, 18 May 2006 06:00:34 -0700 (PDT)
From: "Fred Rafael Rednor" <fred_rednor@yahoo.com>
To: Classic Rendezvous <classicrendezvous@bikelist.org>
In-Reply-To: <446C5EB9.7050908@optusnet.com.au>
Subject: [CR]Re: 1975 Peugeot PR10 Geometry

     You have to look at more than the angles. What is truly importatnt is the setback of the saddle with respect to the bottom bracket. It's possible that the seat tube angle - even if steep - was chosen to work properly with a seat post and saddle configuration that yeilds the same amount of setback as one would expect from a shallower seat tube angle.
     That's actually how a number of Italian frames from theat period worked. That is, they had steep seat tubes and short top tubes. Once you properly positioned the seat, the setback and the effective top tube length were just right. Perhaps Peugeot was doing the same thing during that period?
      Fred Rednor - Arlington, Virginia (USA)

--- "P. Lynn Miller" wrote:

> Ken,


\r?\n> I agree with you, photos cannot be completely trusted, that

\r?\n> is why I

\r?\n> have asked the list for help. When I did the numbers using

\r?\n> photoshop and

\r?\n> illustrator, I was stunned. I have two riders so far that are

\r?\n> confirming

\r?\n> my numbers from actual bike take-offs.


\r?\n> I am very surprised at geometry. Especially if the PX10 of

\r?\n> the same

\r?\n> vintage has similar angles. The PX10 gets a lot of coverage

\r?\n> here in the

\r?\n> list and so I assumed that its geometry would be typical of

\r?\n> the

\r?\n> 'established' standard. But is is far from it. With a seat

\r?\n> angle of 75

\r?\n> and head angle of 76, that is steeper than many track

\r?\n> machines. One

\r?\n> rider even mentioned that he had notice that his bike's

\r?\n> angles seemed

\r?\n> steeper than a fellow riders track bike when in a rack

\r?\n> together at the

\r?\n> coffee shop.


\r?\n> So I am very interested in hearing from Peugeot riders of the

\r?\n> PR10 about

\r?\n> the handling of the bikes compared to other bikes. Also does

\r?\n> anyone if

\r?\n> the PX10 had the same specs. From the photos I have seen, it

\r?\n> would

\r?\n> appear that way.


\r?\n> Does anyone know why Peugeot would have spec their bikes like

\r?\n> this? To

\r?\n> be different in a French way? A trend at the time? A famous

\r?\n> racer had a

\r?\n> bike with these angles?


\r?\n> Just curious,


\r?\n> Lynn Miller

\r?\n> Sydney, Australia

\r?\n> http://www.chainringtransitauthority.com

\r?\n> /

\r?\n> Ken Freeeman wrote:/

\r?\n> > /Generally I'd be cautious about measuring angles from

\r?\n> photos. We want the

\r?\n> > numbers to be good to within a degree or less, and I've

\r?\n> found the camera

\r?\n> > position needs to be perpendicular to the bike to see the

\r?\n> frame tubes

\r?\n> > accurately. A little bit of bias causes the front and rear

\r?\n> wheel diameters

\r?\n> > to "read" differently, and if I see this I tend to doubt

\r?\n> the frame numbers I

\r?\n> > get.

\r?\n> >

\r?\n> > The geometry that's been estimated for this bike is odd,

\r?\n> but if you like the

\r?\n> > ride, it isn't bad, right?

\r?\n> >

\r?\n> > In Tony Oliver's great book "Touring Bikes," he makes a

\r?\n> good case that

\r?\n> > "proper" touring bike geometry is driven by the expected

\r?\n> terrain and usage,

\r?\n> > and hence he demurs in stating any single design criterion

\r?\n> for touring

\r?\n> > bikes. What he liked for his Welsh environment and

\r?\n> customers is not

\r?\n> > necessarily what would work in the US or Oz. Plus, I think

\r?\n> most riders

\r?\n> > acclimate to variations in handling./