Originally Posted by
Carbonfiberboy
Ahaa. Well, that's simple then: your cassette is outside the limits of your RD. You either need a different RD or a Wolftooth or similar extender. B screw has nothing to do with it. You're outside your RD cog size limit. I've been assuming that this is a stock tandem. Apparently not.
It’s stock, or at least how I got it from Santana. It was new old stock when I bought it, and they did a bit of downgrading of some of the components. Santana had just moved to 10 speed, mine’s a 9. I remember complaining to Bill about several shifting problems—he thought most of them were eliminated with the 10 speed system, but didn’t think it was enough of an improvement to be worth upgrading. I suspect between the 160 mm spacing, the small frame of the bike, and the briefly used double boom tube some incompatibilities were created.