Would I be right in concluding that the use of a NuVinci hub will allow a higher ratio of human input power to machine input power than, say, a Nexus hub or derailleur gears? and why is the stated torque for a Bosch motor less for a NuVinci hub than derailleur gears? Finally, does anyone know what the stated torque is for the newer (36v) Panasonic motors?
Can anybody tell me why I can buy a 125cc motorbike or a halfway decent second hand car for the price of a mid range pedelec?
The NuVinci is less efficient than derailleurs despite their claims and probably only matches hub gear efficiency. However, it has a higher torque ratio than the other internal gear hubs, so you could certainly input more in total, meaning more from you is handleable.
Bosch specify a lower power unit for use with hub gears since some of them can be more fragile than derailleurs.
Panasonic don't usually issue torque figures for their crank units. Since the basis for such figures on other makes of unit have been variable and power phase downs and torque input application ratios are at different points, such comparisons can be meaningless. As ever with e-bikes, only trying oneself by riding them is a reliable guide for suitability.
As for vehicle pricing, it's down to market size. The e-bike market is very small and each importer often handles very few machines each year. Therefore the margin per bike they have to add to cover basic costs and survive year upon year can be large. I know of importers who have started by doubling the UK arrival price and then add VAT, and they don't drive Rolls Royces.
If ever e-bikes sold over 2 million a year in the UK like both bicycles and cars do, the prices could plummet.
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