I like how the Spartamet engine is nice and low on the bike - it drives the hub directly, unlike Frank's Bike Bug's spindle drive or other bike engines that use a wide-diameter add-on belt pulley. But I worry a bit about what kind of vibration the Spartamet experiences. I just encountered this factoid the other day, that electric hubmotors die young because they receive the full vibration of the wheel on the road. Bike motors like the Whizzer and modern equivalents that put the motor in the center triangle enjoy a relatively smooth ride right in the middle of the wheelbase, but the Spartamet is right there on the hub. That looks rough.
That got me thinking about these suspension wheels I've been seeing in the news:
Something like that could make modifying existing bike with add-on motors a lot more comfortable, and could inspire people to get on their bikes again.
I clicked 1marcelfilm's liink - there's lots of good instructions there on how to keep the Spartamet running and healthy. THAT's cool.