Generally, monowheels are that wacky, wildly futuristic carry that we lump in the same category as hoverbikes and jetpacks: strange, currently impractical, but very cool. Not content with waiting for the distant future, [Sam Barker] made his own electric monowheel. (Video, embedded below.)
The hardest part of any monowheel is that the outside rim needs to stand huge abuse. It supports the weight of the car and offers many of the structural integrity, but also is the implies of propulsion. [Sam]’s first thought was to use a trampoline frame as it is a round and reasonably durable tube steel. He 3D printed the rollers that connected the subframe to the trampoline frame. flat bar stock was used to make the angles inside the subframe and straight tube steel connected the inner frame into a trapezoid. The trampoline frame was welded together and on the first test spin, it broke aside from the stress. It simply wasn’t strong enough.
Not to be dissuaded, he found a company that bends steel into customized shapes. He stole the e-bike kit from another bike he had converted earlier, and the wheel was turning. Some handles and foot-pedal later, it was time for a proper test drive. Overall, the result is pretty outstanding and the double-takes [Sam] gets while riding down streets in town are wonderful. If you’re wanting to scratch the monowheel itch, check out this wooden monowheel.