Originally Posted by
bulgie
I know this is C&V but I'd shoot for something a bit more modern. A Burley, Trek, Cannondale, Raleigh, Kuwahara, maybe one of the less-expensive Santana models, can often be found pretty cheap. Sometimes after the owners gave up on selling it for their original inflated opinion of what it's worth. Tandems are hard to sell, and often go for less than the value of the parts.
My main complaint about this one is the shallow seat tube angle, which combines with the short rear TT to put the handlebars very close to the pedals. Not a dimension we're used to thinking about, but in the extreme like this, it become a problem because the stoker cannot stand, ever, because her knees will be hitting the handlebar. Or if they clear a little, you still can't stand when the handlebars are that close to your knees. You can't get your center of gravity over the pedals. Maybe that'd be acceptable to someone who never ever pedals standing, but the back seat of a tandem is less comfortable than a single, so standing now and then to get some blood flowing "down there" becomes more important. The shallow STA means more of your weight is on the saddle; even hard pedaling doesn't reduce the weight on the saddle much. Hard to unweight for bumps too.
Sorry to be so negative, but I've been through this a lot of times. The number of happy stokers on these curved seattube bikes that I've known is, um, I might still be waiting to meet the first one.
Mark B
This is partially why I'm thinking about selling my Colin Laing curved-tube. Stoker can stand only with great care and effort, even though she's about as small a stoker as fits on the frame and her bars are as far forward as possible. I don't even know if I'd get what it's worth for it. Could be a bit of an albatross even with the artisan builder cachet.
Front drive was preferred by classic constructeurs like Herse and Singer. Main advantages are increased chain life (chain bushes only wear when touching a sprocket, which they do less than half as often) and no chainline issues when cross-chaining. Chainline becomes a non-issue since it's the angle that the chain cares about, not the actual lateral displacement. Singer in particular used that fact to put 4 rings up front for a super wide range, which is possible but impractical when the crank is in the rear (or on a single bike). On a front-driver, there's no downside to a quad. Also with front drive you don't need the indent in the right side chainstay for chainring clearance. Oh and one minor advantage has been mentioned, that cap'n can see and hear the front shifting and any rubbing.
Downsides are mostly the extra weight of that much chain, and sometimes the rear derailer needs help keeping that chain tight enough to not sag too much or flip around. Not all rear mechs can handle it well. The old Cyclo that attached to a chainstay braze-on was perfect for that because it's spring was like a screendoor spring stretching forward under the chainstay, and you could easily just swap in a stronger spring of the same length.
Modern builders have almost 100% dropped the idea. Not sure which downside most affected that collective decision; probably fashion had a large part in that. Of the "real" (non-fashion) reasons I'd say the main one is the need to use certain derailers that have adjustable spring tension. Less of a problem for a C&V fan since there were several to choose from BITD. Now, I don't know, I don't play with modern derailers at all but I assume they are not adjustable, is that right?
I love front-drive on my tandems for the reasons you describe. The M952 XTR derailleur is fine for it, because it has a couple spring positions you can put the cage on if you dare to disassemble the thing. I would like to try a modern MTB derailleur, with the "clutch" that stops the chain from slapping and sucking. I wonder if these would be even better in this application. For the Le Cyclo, I've mostly just seen two original Le Cyclo springs ganged up together and used "in tandem". Ha. Ha.