Originally Posted by twocicle

Just IMO, I think if you want to use standard/single FSA MegaExo bike cranks you would be better off implementing this with a right-side drive and installing the cranks on their proper sides.

We currently have this setup with FSA SLK Light cranks (double front, triple rear) and a Gates CDX/Centertrack belt drive on the outside of the triple. A timing chain would be easier to setup than the belt drive as the chain would require less space and less precise alignment front to rear. This setup allows us to use 1-130bcd ring in the middle position of the triple spider, and 1-74mm ring in the granny/inner position (we are running 48t/30t chainrings).

The right-side drive does not torque the rear axle and load up the BB in the same manner that a crossover drive does. I would be curious if the FSA tandem crankset has a beefier rear axle and also the bearing cups might differ than the single double version. With right-side drive it doesn't matter because most of the pedaling forces are cancelled out at the timing + drive.