Bamboo frame? That’s how good the new eco mountainbike is

By Stefan Weißenborn

Originally published in Welt, June 2022.

With wheels made of bamboo, you’ll be noticed on the street – but the rustic look is a matter of taste. What does the bikes made from the renewable raw material offer? Special driving characteristics and an ecological advantage. But you have to shell out a few thousand for that.

A bike made of grass? You could put it that way. Because bamboo belongs to the family of sweet grasses. So much for the fun fact. When bike manufacturers make their frames out of bamboo, they also cite tangible benefits. The renewable raw material offers smooth driving characteristics and is particularly environmentally friendly in production.

However, the idea of bamboo bicycles is not new. In view of the triumph of steel as a frame material in the course of industrialization and later of aluminum, it only fell into oblivion.

In 1894 the world’s first bamboo bicycle was made in London and in 2005, the American Craig Calfee brought bamboo back to life in frame construction. There are now a number of companies that rely on the raw material – including the German manufacturers My Boo, Pine and Faserwerk. The Swedish manufacturer Eker (in English: spoke) has also been selling bamboo bicycles since 2021. We took a close look at the Stark model – a hardtail mountain bike.

The purpose

The Stark’s steering or head tube angle is 70 degrees – steeper than a downhill MTB.

Eker markets the Stark model as a cross-country mountain bike. This makes it something of a racing machine among mountain bikes. Cross country is the only mountain bike discipline that is Olympic.

Compared to fullys, i.e. full-suspension mountain bikes, as a hardtail it only has a suspension fork, but a rigid rear. The purpose of use is more sporty than most full-suspension all-mountain bikes.

The technique

The production technology is particularly unusual. It takes 80 hours to make a frame, says Eker co-founder Stefan Krisch, “everything is done by hand”. It begins with the harvest: suitable tubes are harvested by hand in the bamboo forest in Uganda, and the frame is manufactured in the capital Kampala. Final assembly takes place in Sweden.

80 hours: According to Eker, that’s how much manual work goes into every bamboo frame – from harvesting the cane to painting it.

In addition to bamboo, the bark of the Mutuba tree is also used in production. Together with an “environmentally friendly” epoxy resin, which is largely ecologically produced, it is used to connect the pipes: “We cut the bark into strips and wrap the pipes in a specific pattern in order to achieve maximum strength in all directions”, says Krisch about the procedure.

The frame parts made of bark can be recognized by their darker colour. “Because each tube is unique, producing repeat quality bike frames to a tight specification is a huge challenge,” says Krisch.

Every tube is different. The frame of the test bike weighs 2905 grams, but can be between 2400 and 2800 grams in size M. “The weight of each frame varies depending on harvest time and other aspects of the bamboo material,” says Eker, who gives the frame a five-year guarantee. “Due to the high fiber content, our bamboo frame will not break even under heavy loads or direct impacts,” he says. In addition, the material, although a natural product, is protected against wind and weather.

A lot of effort: The parts made of tree bark are formed by hand. To make the frame weatherproof, it is coated several times with clear varnish.

To do this, Eker not only coats the inside of the tubes, but also applies four layers of clear lacquer to the frame in the last production step. “Weather resistance and aging tests under Nordic conditions” could not have harmed the material in summer or winter.

But the biggest advantage over common frame materials such as aluminum or steel is ecological: According to a report by Duke University in North Carolina, the production of an aluminum bicycle frame causes around 250 kilograms of CO2, while a carbon frame causes 67 kilograms of CO2. The opposite happens with bamboo: As a renewable raw material, it binds CO2. “According to our calculations, the bamboo used for an Eker frame corresponds to absorbing 773 kilos of CO2 from the atmosphere,” says the Eker co-founder.

Equipment, accessories, peripherals

The bottom bracket on the bike is generally exposed to great forces – the Stark leaves nothing to be desired in terms of rigidity in this area, even when pedaling out of the saddle on the test rides.

Eker uses components from well-known brands such as SRAM and RockShox. The hydraulic disc brakes and the shifting components come from the US supplier. The rear derailleur, crank, sprocket set and chainring (32 teeth) are part of the ambitious GX Eagle entry-level MTB group. The cassette with sprockets from 10 to 52 teeth offers a transmission range of 500 percent, spread over twelve gears.

The 100 mm suspension fork comes from Rockshox (model Judy Gold RL 29′′). The 29-inch wheels are mounted on quick-release axles. Michelin studded tires, model Wild Racer (29′′x2.1′′), were mounted on the test bike. However, you can choose your own setup; two higher levels with better components can be clicked on in the web configurator, which means that the price can almost be doubled. Eker also accepts special requests for individual requests.

The riding impression

“Our bamboo frame is lightweight, durable and gives the rider a positive level of flexibility without being too soft,” says Krisch. And indeed: when in the saddle I never have the feeling that the strength I bring in is lost in the frame. At the same time, the frame is pleasant to ride: In conjunction with the wide tires, it absorbs a lot of slight bumps and offers a level of comfort that you are not used to from a commonly rigid aluminum hardtail.

In short: the mix of the damping properties, the flexibility and efficient stiffness feels successful. And the bamboo look adds an extra effect: wide-eyed passers-by and people who enquire about your bike, is engrained in the vintage-look of the bicycle.

The price

The Stark costs from 3900 euros in the basic configuration. Things like pedals (from 63 euros) and bottle holders come extra (from 15 euros). If you don’t want the rustic bamboo look, you can order the frame in black – for a surcharge of 110 euros.

The conclusion

The perfect bike for eco off-road racers with the necessary change – that’s how you could characterize the Stark: It’s expensive, but good for your personal CO2 balance. You would get an e-mountain bike for the same price, albeit an entry-level one. The Stark, on the other hand, rides a league higher and is an eye-catcher with an individual look, which combines the special riding characteristics of a bamboo frame with the ecological bonus.