Although purpose-built electric bicycles are becoming increasingly popular, we’re also seeing more products that are designed to give regular bikes an electric boost. Some of these take the form of a motorized wheel, while others are motors that engage the bike’s existing rear wheel. One of the most recent examples of the latter group is go-e’s ONwheel, which hangs beneath the bike.

The ONwheel motor is mounted where the two chainstays meet the bottom bracket – the location in which a kickstand would ordinarily go. This means that users who already have a kickstand mounted there will have to take it off, and replace it with one mounted farther back on the chainstay (which go-e offers as an option).

A sensor detects when the user starts pedalling, then automatically moves the ONwheel’s swingarm into place, causing its spinning roller to press up against the rear tire. This provides some powered assistance to the rider, the percentage of which can be adjusted using either a hard-wired handlebar control unit or by Bluetooth using a smartphone app.

That app can also be used to set the output and top assisted speed of the motor, in accordance to local regulations. Settings range from 250W/25 km/h (16 mph) up to 800W/45 km/h (28 mph). Additionally, it displays data such as battery charge level, current speed and estimated electric-assisted range remaining, plus it allows the motor to be locked with a PIN when the bike is parked.

That said, it’s probably a better idea to just pull the 850-gram (1.9-lb) motor off its quick-release mounting plate when the bike is left unattended, which the designers claim can be done in just a few seconds. It’s also possible to turn the motor off when riding, for those times when assistance isn’t needed.

Power comes from a removable cylindrical 25.2-volt 200-Wh lithium-ion battery pack, which sits in a bottle cage-style holder. A four to five-hour charge (using the included charger) should be good for about 60 km (37 miles) of riding.

And yes, the ONwheel could get pretty wet down there, which is why it’s water-resistant – the recommended cleaning method is to simply hose it down. It does look like it might also end up getting a few whacks in that location, though, so things like riding off curbs might have to be taken off the menu.

If you’re liking the sounds of the ONwheel, you can preorder it via go-e’s current Kickstarter campaign. A pledge of €499 (about US$568) will get you one ... if everything works out. The planned retail price is €599 ($682).

Sources: go-e, Kickstarter

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