Tandem Cycling - Need some help with project

Hello everyone

I have some questions about tandems. I've had an old tandem from a friend. But he needs some cleaning. But he has no gears, now I was thinking to put a wheel with Hub gear. Is this posible without changing to much?

kind greetings

How old of tandem? Is there a brand name so we can guesstimate a starting point? Was it once set up for multi-gears? Budget? Is the Frame in good enough condition to be worthy of the investment in a new rear wheel and chainring? Tandeming is a great shared experience, but if the frame is a noodle, or whippy, it can turn off the stoker very quickly. Are you planning on hills or touring where you would need the gears? Our Samba is a early ninties vintage, but it is not going to get much faster till I lose lots of weight (clydesdales, ya know) but their are enough elevation changes where we ride to utilize the 21 gears we have. I have thought about going to 9speed freewheel to replace the current seven speed, but mods have a way of cascading into the next tax bracket.

there are mostly European hubs that are used in tandems, and recumbents like Greenspeed, but they are pricey. Rohloff-German and of course Shimano Nexus hubs. Tandem rating due the torque 2 riders put out is the kicker.

I have two Schwinn Twinns that I am planning to update with Nexus-7 hubs this spring. One is a single speed, the other a five-speed. I loan them around the neighborhood for anybody wanting to try them out. The single-speed will get a nexus-7 rear with coaster brake (mainly because it already has one), and I'm adding a drum brake front hub because the current rim brake is pathetic (if it has gears for going up hills, it better have brakes for coming down). I haven't decided on the brakes for the other but I may include the outboard nexus drum as well as both rim setups (Sheldon had suggested the nexus drum would not be a great option however).