With the wonders of modern technology you can see one in action, albeit
briefly and on an OT bike:
http://www.youtube.com/
This page: http://www.frankb.us/
for retrodirect. It has links at the bottom.
Jeff Wybrow Melbourne, AUS
On Mon, 10 Sep 2007 23:02:55 +1000,
<classicrendezvous-request@bikelist.org> wrote:
> It was something called a "retro-direct" system and many Hirondelle bi
kes
> used it from 1924 to just before WWII. A couple other French
> manufacturers
> produced similar derailleur and chain systems including one named "Le
> Crack"
> (yes, really). They are mentioned only very briefly in "The Dancing
> Chain", but
> I can't figure out how they work. In the book it shows a double pull
ey
> device mounted just behind a crankset which had TWO chainrings - thou
gh
> I see
> only one on the PBP bike. So, I guess you'd have two speeds in the
> back and two
> more up front... that is, unless the chain routing somehow multiplied
> the
> possible number of different gears you might achieve?
> I'd sure love to see that Rube Goldberg chain routing in action!
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