FAKE NEWS IS EVERYWHERE: Scooter Build, Pt. 6

So remember all that hub-bub I made about not being able to find a suitable brushless DC motor and blah blah blah back in Part Three and then again in Part Five of this slow motion train crash that is this Medium-based build documentation?

It turns out that was fake news.

I ended up buying a brushed motor as per The Master Plan and it arrived in fine working order direct from China by way of California in just a few days. After looking the motor over and learning more about the torque and speed specifications of my purchase, I became acutely aware of how underpowered my scooter would be should I utilize the brushed motor in hand. Digging revealed that the manufacturer of this motor recommends at least a two-stage reduction (meaning two sets of pulleys/gears) with a pretty large ratio between each stage to obtain a decent degree of forward (or backward) motion. Ultimately, this would mean a top speed of about 15 miles an hour and a hell of a time attempting to align and build a gear reduction scheme for the motor within the frame. Such a system would also consume valuable interior space and would limit my options for suspension and swing arm design. Further, while the motor is definitely beefy- about the size of a large soup can- the shaft is not. It’s about 12 millimeters in diameter at most and extremely short with no keyway or flat spot for a grub screw. Additionally, the end of the shaft is threaded which further reduced functional length to the point where there would have barely been enough room for any type of mounting at all.

I had just about resigned myself to my fate of infinite fabrication and lemming-like speed when the almighty Zeus conspired with Minerva to shoot a lightning bolt of brainpower up through my left ass cheek into the dormant parts of my brain responsible for higher order thinking.

What about Amazon?

Yeah, what about Amazon? Forgive my shame in not trusting in the power of Amazon. As a loyal Prime customer, I should’ve known that Jeff Bezos is always waiting for an opportunity to take my money. For the comparatively low sum of $209USD, I was shipped a well-reviewed 1100 watt (almost half a horsepower more than the brushed motor) hub motor, an apparently skookum motor controller, and a whole bunch of control mechanisms including a super sweet Speed Racer-esque twist grip throttle with a big red button. I have no idea what the button does but it’s big and red. I will push it again and again.

Hub Motors are Beautiful

The hub motor is the platonic ideal of e-vehicle motion as it basically eliminates gearing and transmission problems while providing a substantial amount of torque. This is a gross over-generalization however it seems a decent rule of thumb that the larger a brushless motor‘s diameter, the higher the torque output. At about 11 inches across, this is the most diameter-y motor I’ve had the pleasure of handling in person. The instruction manual promises approximately 20 foot-pounds of torque(!!!) at full power. While that figure may seem ludicrous given that a 2,800 pound Toyota Corolla’s engine is rated at about 128 foot-pounds of torque, everything that I’ve seen and learned about so far suggests that the 20 foot-pound figure is entirely plausible. This means that I’m going to burn rubber all the way up to 25 miles an hour which will totallymake up for the fact that I’ll only be going 25 miles an hour.

I am Jack’s destroyed tire.

To put this all in perspective, I paid about $180USD for the brushed motor with motor controller. Fortunately, a merch return was possible. More on that in a moment.

I am pleasantly surprised with the overall structural quality of the rim and components. The wheel is double walled- meaning that there is an inner and outer shell- which is preferable in the world of wheel design as it dramatically increases strength. The spokes are numerous and array out directly from the center point of the hub; this also increases strength. This arrangement of spokes differs from what is normally seen in some bicycle and lower-end motorcycle wheels where the spokes radiate outward from the hub along a path roughly tangent to the circumference of the hub itself. The potential crush-factor is higher with those off-angle spokes because physics. The ultimate sign of quality is the homebrew installation instructions that came with the wheel. While the translation is a little rough in parts the instructions are detailed, thorough, and include a section on how to trouble shoot potential electromechanical issues should they arise. They even included instructions on how to properly set up a multimeter for testing the controller.

Instruction manuals are the unsung heroes of quality assurance. No one ever writes home about the instruction manual because it’s just not sexy but at the end of the day, an even halfway decent manual is a surefire sign that the factory gives a shit and is trying to go above and beyond with their product.

A new tire is en route to my house for this wheel. I’m going to try to mount it myself. The Internet tells me that should be fun…

Until we meet again.