I noticed in a another thread
http://www.bikeforums.net/showthread...on-Our-new-RT2 that there was a heated discussion about stability of a tandem/recumbent in relation to the COG/BB location.
I had my own thoughts and figured why not bounce them off of the engineers in the group.
In my days as a motorcycle racer we were taught that:
Stability was entirely governed by the rake and trail given that the wheel size did not change. A taller wheel is harder to deflect from direction than a shorter one, but this is a separate issue.
Speed of that one could go from full upright to full lean and back was dependent on how far the centre of mass was from the COG. If the COM was below the COG would fall into corner slow and pick up fast and opposite for above the COG.
So back to the other thread in my experience the whether you change the BB height or not it will not change the stability of the tandem only speed up or slow down the change in lean angle.
OK over to the engineers.