Mark Stonich's solution is more elegant that what I did twice for Town & Country tandems that have the same problem. But, my route worked, so I'll outline it. If anyone can't follow it and is really super-interested, I might take a picture of the damaged goods.
1) Parallelogram FDs come in at least two flavors. The most common one (illustrated by Mark) has the cage coupled to the parallelogram with something on top of the cage. The other flavor, typified by the old Shimano Titleist, has a parallelogram piece tack-welded to the back side of the cage instead.
2) Take a Titlist or equivalent and drill out the tack welds to separate the two parts.
3) Brass braze a small circle cut from a spare piece of seat tube or something to the parallelogram piece. This serves to space it out further, which may not be needed. T&C tandems had something like 74 mm. BB...
4) Rebraze this assembly to the cage, but make two changes: a) move it forward about the thickness of Mark's spacer (maybe 2 cm), to compensate for the fact that the tube is so much further forward than on a normal frame. b) tilt it to match the curve of your outer chainring.
If you're careful and use lots of flux, you won't damage the chrome too much. Heck, I even sacrificed a second cage to make a long cage version once. I think we ran this with 28-49-54 cogs when we were young and wild and strong. But I no longer remember that.
ALTERNATIVE FOR DOUBLES: Find an old simplex or Campy "plunger" FD, since that allows rotating the cage. but it still won't be placed far enough forward.
harvey sachs mcLean va.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ At 1/19/2010 06:11 AM -0800, William Crowell wrote:
>>What does one do for a replacement front derailleur on a Schwinn Paramount >>tandem with the bent stoker's seat tube?
Here's what I did for a customer's Paramount Tandem.
105 braze on FD + adaptor for using BO derailleurs on non-BO frames +
spacer made from 3/8" aluminum
http://bikesmithdesign.com/
Because the angle between the seat stay and seat post is more open than normal, a 20t spread uses up all the derailleur's capacity. Would be a more complicated piece, but not tricky to make, to compensate for this.