Calling Pastor Bob. Come in, Pastor Bob...

We've recently started experiencing a mostly arrhythmic crunchy-bumpy feeling through our feet on the tandem. Adjusting the RD doesn't fix it. I thought it must be a BB bearing, that I'd have to pull the BBs apart. If we lighten up our pedal effort it would sort of stop. But today we noticed that it was specific to one sprocket, #2 out of 5. Unfortunately it is the sprocket I use the most. Must be a busted tooth or two or three. We've busted 'em before. (My sweetie is such a powerful stoker, all 5'1" of her. That must be it.)

So I check the FW at our next stop. Nothing broken, nothing bent. Backpedaling the cranks revealed nothing. Well, I figure one or more of the struts from the inner edge to the outer ring with the teeth might be cracked. Left to itself it just sits there where it supposed to be. Under stress it might be displacing to the side, possibly because the crack is on an angle.

We did the last half of today's ride without using that sprocket. I missed it.

Anybody got suggestions on what else it might be? I have another FW with similar gearing to use while this one is begin repaired. But this one is nice because the body is stamped "Tandem" and can handle the higher load. Except when the gears can't.