Chainless electric drive system “Free Drive” for bicycles (2021)
I cannot see why anyone would prefer this for a bicycle that is at all shaped like a normal bike. An integrated mid-drive ebike is just all around much more efficient.<p>Direct hub motors for large (bike size) diameter wheels frankly suck at this point in time. You need to have much more copper to efficiently drive the motor at the power levels required, because RPM is so much lower with hub motors. Not being able to use RPM to your advantage is such a huge efficiency hog at low speed acceleration, which is a lot of how people use ebikes.<p>If this is using an internally geared hub, my point is moot; however that comes with it&#x27;s own drawbacks. It&#x27;s incredibly hard to get heat out of a geared hub motor efficiently. Your motor is encased inside the hub, with no direct connection for heat to escape, and you generally have way less copper available to heat soak.<p>Mid drives get the advantage of mechanical gearing, and can be built in such a way to allow very little heat generation to begin with, but you also can easily cool something in the frame compared to a spinning hub.