The split hub was designed to allow both an electrical uphill assist and a derailleur drive on a single rear hub. It has two silent freewheeling clutches, and both sides of the hub are held in place by the spokes alone. This is a controversial approach initially devised by Dan Sodomsky of eCycle, however after riding on split hubs for a number of years without ever bothering to true the wheel (even after replacing broken spokes) I am convinced that this is a practical viable system.
The hub assembly with the electrical beltwheel on the left and the derailleur on the right is shown, as well as the various hub parts that make up the split hub. The overriding requirement is that the electrical assist motor must drive the rear wheel.