How to electrify your normal bike

From powered wheels to friction drives and folding e-bikes, we explain all

With all the noise currently being made about electric bikes, you might be thinking, ‘That’s all very well, but I want to keep my existing bike’. Well good news – ol’ faithful can be rigged up with an e-bike conversion kit.


There are a number of ways to electrify your existing bike and start zooming up those hills: you can fit a powered wheel, either front or rear; you can attach a drive unit to the bottom bracket; you can fit a motor above the rear wheel and drive it via friction; or, most sneakily, you can conceal a motor in the seatpost. (If you choose the latter, best you don’t go racing it.)

None of these options are particularly cheap, nor easy, but they’re viable with most bikes, whether you ride a hybrid, mountain bike, tourer or road bike. Many can even be done by the home mechanic, if you’re feeling handy and have an afternoon spare.

So what are your options? Let’s take a look…

Powered e-bike wheels

The omni wheel can be easily swapped in to replace your front wheel

This is probably the most practical option for many people – swap out one of your normal, non-powered wheels for one with a special hub that contains a motor, battery and the gearing needed to turn it. Sounds simple, but the main downside is that it adds rotating mass to your bike (which feels harder to accelerate than non-rotating mass).

One famous example is the Copenhagen Wheel, which uses technology developed by MIT and comes with either a 250-watt or 350-watt motor. It has a range of around 30 miles (48km), and a top assisted speed of 20mph (32kph). Release has been delayed a number of times, but you can preorder it for $949 from

One product you can buy today is the Omni Wheel, designed to replace your front wheel, which is claimed to have a 40-mile range (64km). You get a press-and-go throttle on your handlebars for when you want a boost, and a wireless display that lets you adjust the amount of assist you get. It costs $999 from

Finally, there’s also the FlyKly Smart Wheel, which is operated via a smartphone app. It comes in four sizes: 28in for city bikes, 28in for mountain bikes, 20in for folding bikes, and the hub on its own. It claims a range of 25 to 60 miles (40 to 100km), and will assist you up to 16mph (25kph) with its 250-watt motor. Impressively, its said to be around half the weight of the Copenhagen Wheel, at 3kg. It costs $999 from

Rear-mounted friction drive e-bike conversion kit

The rubbee is a friction drive unit that sits on top of your rear wheel
Oli Woodman / Immediate Media

Readers of a certain age may remember earlier incarnations of these in the 1980s/90s: a box that sits on your rear wheel and powers it via friction with a rubber flywheel driven by a motor. Sadly, we never got to fit one to our Raleigh Choppers and Muddy Fox mountain bikes, so we didn’t find out if they were any good. 

The idea hasn’t gone away though – it lives on in devices like the Rubbee, which promises bolt-on electric assistance for nearly any bike. Our own Oli Woodman wrote about them last year, reporting that the latest version weighs 6.8kg and features a 250-watt motor that’ll provide assistance up to 16 mph (25kph). It works with any wheel diameter between 16in and 29in, and has a claimed range of up to 25 miles (40km) before needing to be recharged. At the time of writing it costs €690 from

There’s also the Semcon, which hasn’t hit the shops yet, but promises to be lightweight and portable. It contains a modest 150-watt motor and only weighs 1.1kg according to the inventors, who don’t give an estimated range for it. It works in a similar way to the Rubbee, but rather than sitting on top of the rear wheel, it sits between wheel and seat post. The team behind Semcon say it could cost as little as €100, if and when it goes on sale.

The go-e onwheel powers your rear wheel via friction from underneath

One more slant on this idea comes from the go-e ONwheel, which hangs beneath the bike and presses a powered roller against the rear wheel. It can be controlled either via a handlebar mounted control unit, or a smartphone app, and comes with a default setting of providing up to 250-watts of assistance and a maximum speed of 25kph, with a range of up to 60km. Excitingly, capacity can be increased to 800-watts of assistance via the control unit or app (the makers say: “It is your responsibility to set the maximal limits in the app according to local speed and power limits”.) The go-e ONwheel costs €499 from

Concealed e-bike conversion kit

The vivax assist lets you hide a motor and battery inside your bike frame… but don’t take it to the races

Now we come to the low-key way to do it – hiding a motor inside your bike, so no one knows it’s there. This method hit the headlines in a big way earlier this year when Belgian rider Femke Van den Driessche was found to have done exactly that at the UCI Cyclocross World Champs. Then got a six-year ban, and quit racing (cheats never prosper, kids).

Now as long as you’re not actually racing there’s nothing legally wrong with doing this: some may feel it’s a bit sneaky, zooming around and overtaking people without a big sign on your bike that says ‘e-bike’, but others will disagree. Make your own mind up.

The Vivax Assist is the best-known device for doing this: a kit can be bought for around €2,699 and includes a small 200-watt motor that can be concealed within your bike’s seat tube and drives the crankshaft via a bevel gear, a battery that goes in your bottle cage and provides assistance for at least 60mins of riding, and a handlebar-mounted switch for activating the motor. The makers say it the whole kit weighs just 1.8kg, but must be fitted by a specialist. Vivax Assist can be bought from

Mid-drive e-bike conversion kit

The bikee bike is a mid-drive unit that promises lots and lots of power

Go into any e-bike shop and you’re likely to see off-the-shelf models powered with motors mounted around the bottom bracket, near the pedals. This isn’t just a ready-made option though – you can also buy aftermarket conversion kits with mid-drive units. These have the advantage of placing the weight low down on the bike – making it more stable – but be warned, they can get damaged hitting rocks, kerbs and other obstacles, being so low-slung.

The Bafang 8Fun BBS01 and BBS02 mid-drive motor kits are two of the best-known examples. The BBS01 comes with a 250W motor and costs £330 / $399, and the BBS02 comes with a 500W motor and costs £365 / $525. You’ll also need to purchase a battery kit with charger for around £315 / $399. More info is available at

There’s also the Bikee Bike project on Kickstarter, which is a mid-drive conversion kit that mounts around the bottom bracket like the Bafang 8Fun. The makers say it will come in 250W/500W/850W versions, with a maximum speed of 30 mph (45kph), and a range of up to 60 miles (90km). It’s expected to retail for €1100 when it goes on sale around Christmas 2016 (the Kickstarter goal has already been reached).

Folding e-bike conversion kit

Various e-bike conversion kits are available for the brompton, including this one from nano electric bike

So what do you do if you’ve got a folding bike, and want to join the electric revolution? Well there’s good news if you’ve got a Brompton – a number of e-bike conversion kits are available. They generally work with a powered hub in the front wheel and a battery hidden in a bag mounted on the front.

UK firm Nano Electric Bikes offers kits costing from £710, running on a lightweight 2kg motor. You’ve got the option of using a twist grip throttle or thumb throttle, and they promise a range of up to 40 miles (64km), and a top assisted speed of 25mph (23kph). More info from


In the US, you could check out NYCEWheels, which sells a $1,395 electric motor conversion kit for Bromptons. This gives a top assisted speed of 18mph and a range of around 20 miles, but it must be installed in their workshop. More info from