It wasn't long ago that we tried out the FlyKly Smart Wheel, a motorized rear bicycle wheel that instantly turns a regular bike into an e-bike. Given that it goes in the back, however, it's a little tricky to put on and take off, plus it leaves you stuck with just one gear. Belon Engineering's new Electron Wheel avoids those problems, by replacing the bike's existing front wheel. We recently got to try out an advance demo unit, and it works just as advertised ... although it's a bit of a monster.

The Electron Wheel contains a 250-watt DC planetary geared hub motor, a 24-volt/10.7-Ah/256-Wh lithium-ion battery pack, and sensors that determine if you're riding uphill, downhill or on flat ground. It also communicates wirelessly with an included crank-mounted pedal sensor, to keep track of your cadence.

Using an accompanying free app, you can select the amount of pedaling assistance you wish the wheel to provide, plus you can do things like checking its battery level and tracking your rides. The wheel's maximum pedal-assist speed is 20 mph (32 km/h) in North America, and 16 mph (25 km/h) in Europe, as per regional regulations. It has a stated range of 16 to 22 miles (26 to 35 km) when used for "normal pedaling," which roughly matched up with our test rides.

Installation proved to be fairly easy. The Electron went on more or less like a regular quick-release front wheel, with the extra step of placing its spring-loaded torsion arm against the front edge of the fork. This user-friendliness means that when the battery needs recharging, you don't have to drag the whole bike inside – just the front wheel.

The Electron Wheel's pedal sensor(Credit: Ben Coxworth/

Once we got riding, the Electron Wheel did indeed add some nice pep when riding on level roads, and made hill-climbing a lot easier – it was definitely nice to have the bike's rear gear cluster still in place and usable. There is a slight delay between initially starting to pedal and having the motor kick in, although we've also noticed this on the FlyKly and various full-on e-bikes.

It has to be said, though, that one of the Electron Wheel's defining features is its weight – it tips the scales at a hefty 20 lb (9 kg). While the electric assistance mostly makes up for that when pedaling, it does mean that it's pretty much impossible to loft the front wheel up over bumps in the road, plus the bike becomes unwieldy to pick up and carry around. Not only is it heavy, but it's front-heavy. Considering that many prospective buyers may be seniors or other people who want to avoid undue exertion, that's a fact worth noting.

To put that weight figure in perspective, the similar Omni Wheel weighs almost exactly as much, while the rear-mounted FlyKly and Copenhagen Wheel are both considerably lighter at 6 lb (3 kg) and 12 lb (5.5 kg) respectively. It should also be noted that many dedicated e-bikes weigh in the neighborhood of 50 lb (23 kg) or more.

We additionally found that the Electron's plastic housing did make some banging noises when going over bumps. That, combined with the wheel's high visual profile, means that you're definitely going to get noticed when using it. It would also be nice to see the pedal sensor attach with something a bit more secure than the existing Velcro strap – as it is, it would be very easy for a passing thief to nab it before realizing that it was useless to them.

If the weight and other smaller issues aren't deal-breakers for you, you should be able to get an Electron Wheel of your own in the first quarter of next year, for US$800. It will be available in 26-inch and 700C wheel sizes.

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