Bike of the Week | Hummingbird’s Electric Flax folding bike is made of flax fibre

A sustainable folding bike with a lightweight parts spec 

Hummingbird Electric Flax against a graffiti background

This week, we have the rather unusual-looking Hummingbird Electric Flax – an electric folding bike with a flax fibre composite frame.


Hummingbird says it’s the world’s first folding bike frame made entirely of flax plant fibres and, after walking, is the most environmentally friendly form of transport.

Determining the most environmentally friendly form of transport is complicated, but for more information on the topic, why not check out our long read on how green cycling can be?

Now, though, let’s take a closer look at our latest Bike of the Week.

Why flax?

It’s certainly distinctive.
Oscar Huckle / Our Media

Hummingbird has collaborated with Prodrive, best known for its motorsport experience, to develop and engineer the frame.

The flax fibre composite frame is said to match the strength of Hummingbird’s carbon fibre models. Hummingbird claims flax also offers improved vibration damping.

Unlike carbon fibre, flax is a sustainable material. The brand says the waste generated at the production stage is biodegradable and is less harmful to dispose of and recycle.

Other than some minimal branding, the flax is the star of the show.
Oscar Huckle / Our Media

The frame has a gloss lacquer over the flax fibres, which are fully on display.

Hummingbird says the Electric Flax will accommodate riders from 5ft 1in to 6ft 5in and the maximum weight, including baggage, is 110kg.

The rear triangle is made of CNC’d aluminium and the bike features a full carbon fibre fork.

What is Bike of the Week?

Every fortnight, we’ll bring you a detailed first look at one of the latest bikes (or framesets) to arrive at BikeRadar HQ – from road to commuting, gravel to enduro, and anything in between.

This is our chance to introduce the bike and everything that makes it unique before hitting the road or trails.

Head to our Bike of the Week hub for previous editions.

An updated motor system

It’s a beefy hub motor.
Oscar Huckle / Our Media

The Electric Flax retails for £4,995 and is driven by a second-generation Zehus ‘All-in-one’ 250W hub motor and built in-battery. It’s said to weigh 3.5kg and will cut out at 15.5mph.

The charger connects to the rear wheel axle and Hummingbird says it will take three hours to charge fully.

Hummingbird says the Zehus system is designed to work with the Bitride app, which enables you to customise the settings, as well as monitor your speed and remaining battery life using Bluetooth 5.1 connectivity.

The controls are up at the handlebar.
Oscar Huckle / Our Media

When you connect to the app, it’ll display your battery life and Hummingbird says it can even help with navigation or locating your bike. When your specific motor is connected to the app, you can also ‘lock’ the bike.

The range is said to be approximately 50km on a single charge, which is an improvement of 20 per cent over the first-generation hub motor.

Hummingbird claims this latest motor also offers a 50 per cent improvement in torque.

Folding down

The swingarm and rear wheel tuck under the frame.
Oscar Huckle / Our Media

Hummingbird says when folded, the bike will measure 116x60x20cm.

To fold the Hummingbird, unlock the swingarm quick-release skewer, located near the top of the seat tube junction and lift the bike slightly to fold the rear wheel under the frame.

There’s a quick-release to angle the handlebars.
Oscar Huckle / Our Media

The handlebars can be adjusted to a neutral position with a lever at the clamping area and the stem quick-release can then be unlocked.

The bars then fold to the non-driveside and a clip in place of the bar-end on the driveside grip can hook onto the side of the swingarm to keep everything secure.

The pedals are removable.
Oscar Huckle / Our Media

You can then drop the seatpost and remove the pedals, and the pedals can be slotted into the brake bridge.

The Electric Flax fully folded.
Oscar Huckle / Our Media

A lightweight-optimised parts kit

The build continues Hummingbird’s pursuit of lightweight, with what appear to be custom own-brand parts. This includes the finishing kit and brake levers.

Both the handlebar and seatpost are full carbon, with the handlebars measuring 520mm wide and featuring a 50mm rise.

There’s a reason carbon and titanium are the go-to materials for a lightweight build.
Oscar Huckle / Our Media

The seatpost features titanium hardware and is fastened to the frame with a CNC’d quick-release clamp for folding. Sitting atop the seatpost is an unbranded saddle with carbon rails in a 130mm width.

The brake levers seem to be Hummingbird’s own and are joined to Tektro R539 rim brake calipers on our build, although the spec sheet lists the calipers as Shimano BR-R451s.

It’s a mix of component brands for the drivetrain.
Oscar Huckle / Our Media

When it comes to the drivetrain, Hummingbird has specced a Shimano Alfine crankset with a 48-tooth chainring and an integrated CNC chainguard. The rear sprocket has 12 teeth and joining them together is a YBN superlight hollow pin chain.

16in Schwalbe Kojak tyres are specced and installed onto an ‘ultralight aluminium alloy’ wheelset, of Hummingbird’s own.

The graphics are stickers rather than painted under the lacquer.
Oscar Huckle / Our Media

All-in, the bike weighs 10.65kg, with the removable Wellgo flat pedals.


We’re currently testing the Hummingbird Electric Flax and we’ll bring you a full review soon.