If you want to run two chainrings on a TSDZ2B will both rings install onto the existing spider that is part of the motor or does one need to purchase an adapter? I've seen some adapters for both 130BCD and 104BCD but it's unclear if these adapters will allow installation of two chainrings or merely exist to allow a greater choice of single chainring for the TSDZ2B. I do know from reading on the recumbent forum I frequent that folks have installed double rings but so far I haven't heard back whether they installed them on the existing spider or utilized and adapter of some sort. I do know that the spacing is such that a front derailleur won't work to shift the rings without some modifications. Some folks are simply choosing to leave off the front derailleur and shifting by manually moving the chain. On a recumbent trike (which is what I have), one can actually grab the front chaintube and affect a shift between front chainrings manually while pedaling. Not the most elegant solution, but it's doable. I would prefer to keep a front derailleur but will like switch to flat mount so that I can use the necessary washers and such to achieve the spacing that will allow shifting. Further complicating matters is that I run a Rohloff hub in the rear so I have to be choosy with the choice of chainrings so that I don't exceed input torque for the Rohloff.