The down tube and seat tube are 28.0mm instead of 28.6, or 98% as big as English dimensions. If we consider the effect of diameter to be cubed, as for torsional stiffness, then the metric DT/ST are 94% as stiff. This will be partly offset by the 26mm metric toptube being 2% larger and 7% stiffer torsionally than the 25.4mm English one. So there is a different "balance" of stiffness between the top of the frame and the bottom as it were - maybe that's what people feel.
I tend to think such small differences fall below the threshold of human perception however, or at last get lost in the "noise" of other differences - such as the tendency of metric tubed bikes to have more fork rake.
Mark Bulgier
Seattle, Wa USA
> -----Original Message-----
> From: Joseph Bender-Zanoni [mailto:jfbender@umich.edu]
> Sent: Tuesday, May 22, 2001 5:24 PM
> To: Moos, Jerry; 'Jim Cole'; Classicrendezvous@bikelist.org
> Subject: RE: [CR]RE: Steering geometry now metric tubing
>
>
> I agree about the feel difference. A metric tubed frame feels
> springier. Of
> course this applies to Swiss bikes made with metric tubing also.
>
> Joe
>
> At 03:49 PM 5/22/01 -0400, Moos, Jerry wrote:
> >A matter of opinion, no doubt, but most Francophiles think
> the old French
> >frames feel different, and the metric 531 was definitely different in
> >diameter, so is an obvious, if only partial, explanation for
> the feel.
> >
> >Regards,
> >
> >Jerry Moos
> >
> >-----Original Message-----
> >From: Jim Cole [mailto:jcole@memphis.edu]
> >Sent: Tuesday, May 22, 2001 4:04 PM
> >To: Classicrendezvous@bikelist.org
> >Subject: [CR]RE: Steering geometry
> >
> >
> >Jerry wrote:
> >
> >>[snip]...To me, the French bikes have a wonderful "live" feel,
> >probably due to the long rake as well as the metric gauge
> 531,...[snip]
> >
> >I've never heard that metric gauge tubing has a much different "feel"
> >over other 531 tubing. Have I been missing something?
> >
> >Jim Cole
> >Memphis, TN