Jim Merz wrote: "I used Jubilee front and rear when they were current. I thought they shifted very well. Because the rear was so light, it could get bent if you were ham fisted or crashed on it. Because the Jubilee work for me so well, I tried the Duopar when it came out. The best shifting touring rear at the time, can handle the largest rear cogs."
For those reasons and the high price, the prestige-conscious among tandemists eagerly sought out the Duopar. It turned out to have one "feature" (which nowadays we would call a "bug") that was not very popular: If you tried backing the bike when the pulleys weren't precisely aligned with the freewheel, it would protest mightily by tying up the chain in the weird double parallelogram assembly, at which point the bike would stop rolling back. Never was a problem with singles, since they were so easy to pick up.
I still have a Duopar or two as eye candy on the wall. With the single-pulley Campgranolo "Sport" and the preposterous "Gran Turismo" boat anchor.
harvey sachs
mclean va.