To elaborate a bit, friends of mine have had bikes with both cadence and torque sensors. And I've tried their bikes out. Agreeing with one friend, the bike with the cadence sensor seems to decide how fast it wants to go.
The bike with the torque sensor behaves a lot more like what you're used to from riding a conventional bike. After all, the control input to a conventional bike is torque.
Well yes, because there’s no other input. It’s an on/off switch, the bike just knows that you’re pedaling. Usually there are multiple power levels you can switch between with a button, and those decide roughly how much of a push you get from the motor, but the power curves are all “hardcoded”. It doesn’t feel great for active riding, but it’s adequate for commuter bikes. Torque sensors are actually kind of expensive on their own.
I agree, but would like to point out that sometimes this might not be what you want. I had a bike with a front motor and a cadence sensor that I used for my commute for a few years, and was very happy with the motor just pulling me along while I lazily pushed the pedals with ~zero torque, barely enough to let the bike know I'm there. Basically like pressing a throttle. If all you want is to get from A to B comfortably, I've found this to be superior to a torque sensor, and it was also dirt cheap.
*“VéloSoleX is a moped, or motorised bicycle, usually just referred to as 'Solex', […] originally created during World War II and mass-produced between 1946 and 1988, came in various iterations, while keeping the same concept of a motor with a roller resting on the front wheel of a bicycle”*
This powers the back wheel, though. I think that’s better for propulsion but it seems you’re giving up carrying stuff or a child on the back of the bicycle. Can’t even have a rack there with this contraption.
RAM prices.
(Of course, "capacity" is misleading, as this will be less efficient than a real e-bike.)
The design doesn't work if you have a mud guard or pannier rack. Also unclear how easily it is detached. Do I have to take it off everytime to prevent casual thievery? How do I take it off to charge inside? Does it have anti-theft bricking?
I'm struggling to understand who the target market is.
It has a removable battery so it seems the mechanism is designed to be left on the bike.