Jan,
First, what a great idea to pitch to the builders: build three bikes--one with normal tubes, one with OS top, and one with oversized down. Cost commitment would be big problem for them, but maybe there's a grant somewhere that could be had to fund this project.
Second, if none of them takes you up on it, perhaps there is a contemporary mechanical engineer on the list addicted to steel lightweights who might CAD three identical bikes in a dynamic design simulation and make a virtual comparison.
Best,
Don Wilson
Los Olivos, CA USA
> At 8:11 AM -0700 6/14/06, Don Wilson wrote:
> >Two Questions:
> >
> >1. What would the comparative
> advantages/disadvantages
> >be of using oversize top tubes vs. oversize down
> >tubes?
>
> I am not qualified to answer that, as I never have
> ridden two
> otherwise identical bikes with just different
> diameter top or down
> tubes. However, I doubt anybody else alive today has
> had that direct
> comparison, either. If a builder is willing to make
> two (or better
> three, one standard, one OS top, one OS down tube)
> bikes, Vintage
> Bicycle Quarterly would love to do a test similar to
> the geometry
> test (three identical frames except for the fork
> offset) in the
> Spring 06 issue. We would have at least three
> different, experienced
> riders ride each bike back-to-back and comment on
> the feel, climbing,
> descending and cornering. That would be very
> interesting, and could
> help guide future bike design. We might even wrap
> the tubes in pipe
> insulation, so we could not tell which bike we are
> riding, making
> this a double-blind test.
>
> >2. Did any of the classic lightweight builders try
> >oversized down tubes with any marked benefit?
>
> Rene Herse used to offer it. Mike Kone's "campeur,"
> which I rode at
> the Cirque 05, has that feature. It seems to ride
> quite well indeed.
>
> --
> Jan Heine
> Editor/Publisher
> Vintage Bicycle Quarterly
> c/o Il Vecchio Bicycles
> 140 Lakeside Ave, Ste. C
> Seattle WA 98122
> http://www.vintagebicyclepress.com
>
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