Thanks for the reply. Yes, the triple goes in the stoker's BB. Yes, the spindles are asymmetric and installed with the long end on the right. One more spec, for what it's worth, both BB shells are 68mm wide.

I was just talking with southpawboston (picking up some parts) and he proposed an interesting idea: The two cups are the same thickness. The fixed cup always sits flush with the BB shell, and the adjustable cup usually sits outboard a little more to allow space for the lockring. So perhaps the previous mechanic swapped them to move the spindle to the right in order to get more clearance. Except it wasn't enough.

Another idea is that by using a thicker British spindle (but with ISO taper) it would force the bearing races farther apart, thus moving the adjustable cup on the right further outboard, and the spindle itself half of that distance. I don't know if that's the right thing to do. A longer spindle is the real solution.

Thanks again.