My first question is about the rear spacing. It is 130mm when the road standard in 1982 was 126mm and 6 speed rear gearing. Of course modern road rear spacing is 130mm with 8/9/10/11 rear gears and I believe that modern Tandem spacing is 135mm to 140mm with 9/10 rear gears being the standard. Could I use a modern 36 hole 130mm rear 10 speed hub without issues?
My second question is about the rear brakes. It has two brake bridges and has brake cable braze-ons on the top tube from the front and also braze-ons along the diagonal cross member in the stokers cockpit only to the second bridge. I believe that this is for a stoker controlled "drag brake". Is this correct? Would it be operated with a regular brake lever or with a modified "retro-friction" shift lever?
Thanks for any feedback.
vjp
Sounds like an interesting specimen. Please share some photos.
1) Rear-spacing standard for modern tandems is 145 mm. (Santana uses 160 mm.) This wider standard allows the rear wheel to be built "dishless", i.e. symmetric with spokes on both sides at equal tension or nearly so. This makes a stonger rear wheel and alleviates a notorious Achilles heel of tandem bicycles. Your bike at 130 mm was probably intended for a 6- or 7- speed freewheel or cassette hub, with spacers added to the left end of the axle with the same goal: to make the wheel less asymmetric than a standard hub at 126 mm would have been. (Our Santana Targa from 1989 was set up that way.)
However, there is no reason you can't put a modern 130 mm rear hub in yours as long as your stoker is on the light side. A 40- or 48- spoke wheel would make it more durable but I don't know how much luck you'll have finding 130 mm hubs drilled for that many spokes. You might also find 10-speed chains too fragile for reliable tandem use. I'd suggest sticking to 8-speed cassettes and chains during the working up of an old try-it-see-if-you-like-it tandem.
You could go with whatever you have and rethink things if you start breaking spokes and chains. It'll fit, no problem, it just might not be durable enough for your needs, especially if your son bulks up a lot during his growth spurt. (But by then he might be too tall for it, or too worried about being "uncool" to want to ride with his Dad anyway.)
2) In those days, the only third brake option for a tandem was an Arai drum brake mounted on the rear -- the left side of the hub was LH-threaded to allow the brake drum to be screwed onto it. You're correct: it was a "drag" brake intended for the "set-and-forget" mode, much like a parachute. There were many strategies for operating the drum which I won't go into here since it is unlikely you'll be able to find, or need, a drum brake for what you're likely to use this tandem for. It's necessary only for heavy loads (people or luggage) on long steep descents where speed needs to be controlled. You can't stop the bike with one so you need two rim brakes anyway.
Thanks for posting this here, since the Tandem Forum is mostly people with exotic new equipment who aren't much interested in C&V stuff. However they can help a lot with getting up the learning curve of tandeming itself, no matter what you're riding. Good luck with your project. Please let us know how it turns out.