Tandem Front BB issue

[Scott Fitz]

What is the standard Cannondale front BB setup on tandems? Is it some sort of eccentric thingy? Is this easily replaced/parts sourced?
I've got some weird rubbing vibration feeling coming from the BB area when going uphill and torqueing hard. Almost like a mountain bike knobby tire rubbing on a frame, but it feels like bearings getting rubbed.
Any help would be great before I send this to the aluminum recycler.

 

[black lightning 1987]

I haven't owned a tandem but might be able to look at a friend's. I would expect that the bottom bracket is a standard Shimano mounted in an eccentric. For example, in 1997 all the tandem models used Shimano BB-UN52 bottom brackets. It's likely that you just need a new BB. What year/model is your bike?