There’s been a lot of press lately about an incredible-sounding new ebike product called the FlyKly Smart Wheel. We see gushing headlines such as “This Smart Wheel Makes Cycling in the City a Breeze”, “Effortless Pedalling Through Our Cities’ Streets”, “Keeps You Looking Fly”, and “This ground breaking invention just may be about to revolutionize commuter cycling forever”. The Smart Wheel is an electric hub motor similar to other hub motors that have been available for over a decade, but with a twist: the motor and all the electronics and batteries fit inside the wheel. Furthermore the wheel is controllable through a bluetooth connection to a smart phone. This connectivity enables some interesting features like a speedometer that appears on your handlebar-mounted smart phone, a way to lock the bike electronically, and a way to track your bike if it’s stolen. Pretty cool, but is the Smart Wheel too good to be true? Is it just hype? Decidedly no, it is easily for real. I’d say for people who haven’t yet tried an electric bike, this product will easily live up to the hype. Ebikes in general are impressive; this product is doubly so. And even for those of us who have been using electric bikes for years, we will appreciate this product as an underpowered but masterfully clever version of what we already have. Here are my thoughts in detail.
First of all, is the Smart Wheel even technically possible? Can a reasonably powerful motor and all the batteries it requires really fit inside a bicycle wheel and only weigh nine pounds? Yes. Ebike batteries have been growing steadily smaller, especially when lithium batteries began to replace lead acid batteries a few years ago. And ebike motors have been significantly improved by advances in rare earth magnets and the switch from brushed to brushless (computer controlled) motors. Ebike motors less than five pounds and ebike batteries less than five pounds are not unusual. But is it a good design decision to put everything inside the wheel? It hasn’t been done before for a couple of good reasons. One is that any weight on the wheel reduces a bike’s performance, more so if the weight is closer to the wheel’s rim. I question how much the Smart Wheel’s small motor can overcome its own drag on the bike. It is generally a better design strategy not to put any weight on the wheel that can be put elsewhere.
The second reason I question the all-in-one wheel design is heat dissipation. I know of only one manufacturer who has tried combining the motor and the controller in a hub (Golden Motors) and I’ve heard that their systems were prone to failure from overheating. Batteries also produce heat, so to also add the batteries to the hub compounds the problem. However, the wheel inertia problem will be small for a lightweight wheel, and the heat dissipation problem will be small for a low-power motor.
Another design choice that I (as an ebike mechanic) dislike: this design is proprietary. I like to be able to add more batteries for a long trip, or make repairs with standard parts, or upgrade to a controller that isn’t necessarily the one that came with the bike. These things aren’t possible with this “closed” design.
Lastly, I predict that the Smart Wheel does not have enough torque to be successful in a hilly area, such as Ithaca New York where I live. I estimate it produces 300 to 400 watts of power. This is at the very low end of what’s useful for an ebike. It would only be possible for an ebike to climb hills with this amount of power if the hub motor were in a small rim (such as the 20″ rim of a folding bike) and if the hub motor had internal gears to give it more torque. See, for example, Boxy Bikes’ Featherweight Folder. But the Smart Wheel instead has a direct drive motor (meaning no internal gears) in a large rim (26″ or 29″). I’m certain it would stall out on the brutal hills of Ithaca. And I have a few more minor complaints: I prefer throttles over pedal-assist, plastic tends to crumble after exposure to the salt and cold of a northeastern winter, and regenerative braking, while nice, is generally over-rated.
In most areas, however, the Smart Wheel will be powerful enough, and it meets it main design goals admirably. It is designed to be low cost, lightweight, and easy to set up. It is impressive what the Smart Wheel doesn’t have compared to other ebike kits. It uses a plastic shell, rather than the metal enclosure typical of hub motors, which lowers the weight and reduces the cost. Its low power makes the heat sinks, axle torque arms, and beefy electronics of other ebike kits unnecessary. The all-in-one enclosure further reduces costs by making an external throttle, a rack, and a controller enclosure unnecessary. The absence of external wiring makes it easy to set up and probably more robust since connectors are a big point of failure. Lastly, its connectivity capabilities make an “on” button, battery monitor and speedometer unnecessary, since this information appears on the rider’s handlebar-mounted smart phone instead. It is a marvel of economy.
Which brings me to the thing I like most about the Smart Wheel: the attention it is bringing to electric bikes. The Smart Wheel is nothing new—hub motors have been around for a while—but the attention it’s getting is a pleasant surprise. Americans are finally innovating in the ebike realm, people are excited by the innovations, and a shared vision is emerging of streets filled with bicycles rather than cars.