Summary: Heinzmann motor driving the nearside of the rear hub by a belt, very fast, 25 mph and more. £2500 when new some while ago. Illegal in the UK.
The transmission in the rear hub is unique. The chain drives through derailleur gears into what amounts to a form of differential inside th hub shell. The motor's belt drive the other input to the differential, so the two are summed together as appropriate to the incoming power from each source, providing the drive to the hub drum and therefore the wheel.
Despite this and the Swiss design, it's more about speed than hillclimbing, the latter only average. It has to be pedalled off the mark for the power to kick in.
Complex and unusual drive system makes thorough checking before buying essential. A single UK agent, Vita Electric in Hampstead, London.
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