don wrote:
Don Wilson wrote:
Anyone want to hazard a guess as to what brand this
tandem might be? Interesting rear chain stay socket at
stoker's bottom bracket shell.
http://ebay.com/
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I can't help remarking on these old tandems in general..most use round boob tubes, which have very poor stiffness in this application.
So the builders tended to make the rear sections quite short, to compensate for the inadequate stiffness of the boob tube... this is why you see every sort of additional tube running the full length of these old tandems, at times, to stiffen them up... and why you see very slack seat angles on the stoker seat-tube: to create more space between the stoker and the captain.
nothing worked as well as an oval boob-tube, as seen on Rene Herse and Jack Taylor tandems.
Most old tandems of this kind are barely rideable because of the short stoker sections. The only practical way to compensate is to give the stoker upright bars...but then your stoker can't get his/her back into it properly.
Oval boob tubes are really the only reasonable alternative. I must confess I've always been a little surprised that people like Pogliaghi and Schwinn continued to use the old Columbus tandem tube set with the round boob tubes, long after Reynolds made their tandem set available. Weird. With Pogliaghi it was probably just habit..and his tandems seem plenty stiff..if very short in back..
Schwinn though, go figure..
Charles Andrews
SoCal