There is no more drag than drag of a gearhub. This is basically gearhub relocated to the motor.I wonder what the drag is like on a system like this and/or the energy efficiency?
I see one of the bikes with it fitted has well over 900Wh battery.
Should finally move the game on though.
The benefit of this system comparing with gearhub is not only reduced weight of the rear wheel and mass centralisation but also less stress on the chain or belt because of it does not need transition all that torque from the motor anymore and that stress is only on the gears now.
I noticed he did not answer the question about the motor power. But looking on the exposed motor stator diameter I can tell this is not very powerful unit. The stator diameter is very small. It is probably going to be 1.5 times less powerful than an average emtb mid drive motor. 20 mph is probably going to be top speed on flat on this motor when derestricted.
I hope there will be "cargo" ebike motor soon with integrated speed system with 1500-3000w power so you can go fast. Maybe Bafang will come with such solution.
But this system does have a disadvantage. And this is a safety compromise. With integrated speed system the chainring rotates faster than the crank arms and if the chain catches your pants or your leg somehow slides off the pedal to the chainring area that could be a disaster. It is not a big issue when chainring rotates at the same speed as the crack arms like it does an all the bikes currently.
Ideal solution would be this system with shaft drive and single sided swingarm so there is no fast moving components exposed near your legs no drivetrain maintenance at all, quick and easy release of the rear wheel.
Last edited: