Very interesting notes about geometry!
Generally I'd be cautious about measuring angles from photos. We want the numbers to be good to within a degree or less, and I've found the camera position needs to be perpendicular to the bike to see the frame tubes accurately. A little bit of bias causes the front and rear wheel diameters to "read" differently, and if I see this I tend to doubt the frame numbers I get.
The geometry that's been estimated for this bike is odd, but if you like the ride, it isn't bad, right?
In Tony Oliver's great book "Touring Bikes," he makes a good case that "proper" touring bike geometry is driven by the expected terrain and usage, and hence he demurs in stating any single design criterion for touring bikes. What he liked for his Welsh environment and customers is not necessarily what would work in the US or Oz. Plus, I think most riders acclimate to variations in handling.
Just a few more of my 2 cents,
Ken Freeman (hurray, the rain is backing off!!) in Ann Arbor, MI
-----Original Message----- From: classicrendezvous-bounces@bikelist.org [mailto:classicrendezvous-bounces@bikelist.org] On Behalf Of P. Lynn Miller Sent: Wednesday, May 17, 2006 11:20 PM To: Classic Rendezvous Subject: Re: [CR]1975 Peugeot PR10 Geometry
Charlie,
The numbers all work with no TCO, just by a few mm's. Anyone else on the list with an opinion on the PR10 or PX10, if it has similar geometry?
This geometry is almost 'time-trial' like, moving the rider forward over the BB. It also produces a low trail geometry of about 33mm, a lot less than the current accepted standard of 55mm - 60mm.
These bikes would have to handle uniquely. Is that good or bad?
Thanks,
Lynn Miller
Sydney, Australia
/
Charles T. Young wrote:
> This is fascinating and certainly counter to what I would have expected.
It would be interesting to find if other listmembers can confirm this and
their opinions of the ride. I will have to throw a leg over it tomorrow.
Haven't ridden it with a good wheelset w/ 700c tubulars to get a good basis
for comparison with most of my other similarly shod bikes. It is currently
fitted with 27 inch Rigida alloy rims and what look to be 1 1/8" tires.
>
> My PX-10 is a smaller frame and I'm guessing the angles are more slack.
>
> Charlie
> ----- Original Message ----- From: "P. Lynn Miller"
<lynnmiller@optusnet.com.au>
> To: "Charles T. Young" <youngc@ptd.net> > Sent: Wednesday, May 17, 2006
10:23 PM > Subject: Re: [CR]1975 Peugeot PR10 Geometry > > >> Charlie,
>> >> Thanks for that. I found some photos on the net including photos from
the Peugeot catalogues which are linked from CR. I do not think that your
angles are off by much, since I am coming up with the same angles from the
photos. If you want to get a photo, it needs to be 'square on' is you know
what I mean.
>>
>> Does the PX10 have the same geometry? These are very unusual angle, that
may be the reason why this fellow believes he has never ridden another bike
like his old PR10. Interesting.
>>
>> This geometry goes against everything that is currently in vogue.
Hmmm...
>>
>> Thanks for your time,
>>
>> Lynn
>>
>> /
>> Charles T. Young wrote:/
>>> /These were 76 deg head and 75 deg seat angles - it doesn't look nearly
that steep (and there is no sign of front end impact damage).
Head tube doesn't look overlong as it does on track frames with steeper
angles. I dunno, it might be better to get a photo and have you take it off
from the image.
>>>
>>> Linear dimensions are center to center in cm unless otherwise noted:
>>>
>>> ST 58
>>> TT 58
>>> Wheelbase 1018
>>> Chainstay 42.5
>>> Fork rake 50mm
/