Originally Posted by MacG

As for the double-sided drivetrain, it looks neat, but is not very practical from an engineering standpoint due to the threaded cogs used. There is no way to perfectly align the cogs on both sides of the hub with eachother. If you do get them aligned, I bet it's just a matter of time before riding hard either tightens one or loosens the other just a hair, and they are no longer in phase. When this happens, your chains will be slightly out of phase as well, and will bind up unless you have them loose enough. You could get it to work with lots of dicking around, but it's going to be more trouble than it's worth IMHO.