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Can We Make Bicycles Sustainable Again?

Cycling is the most sustainable form of transportation, but the bicycle is becoming increasingly damaging to the environment. The energy and material used for its production go up while its life expectancy decreases.

Illustration: Diego Marmolejo.
Illustration: Diego Marmolejo.
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Cycling is sustainable, but how sustainable is the bicycle?

Cycling is one of the most sustainable modes of transportation. Increased ridership reduces fossil fuel consumption and pollution, saves space, and improves public health and safety. However, the bicycle itself has managed to elude environmental critique. 12 Studies that calculate the environmental impact of cycling almost always compare it to driving, with predictable results: the bicycle is more sustainable than the car. Such research may encourage people to cycle more often but doesn’t encourage manufacturers to make their bicycles as sustainable as possible.

For this article, I have consulted academic studies that compare different types of bicycles against each other or focus on the manufacturing stage of a particular two-wheeler. That kind of research was virtually non-existent until three or four years ago. Using the available material, I compare different generations of bicycles. Set in a historical context, it becomes clear that the resource use of a bike’s production increases while its lifetime is becoming shorter. The result is a growing environmental footprint. That trend has a clear beginning. The bicycle evolved very slowly until the early 1980s and then suddenly underwent a fast succession of changes that continues up to this day.

There are no studies about bicycles built before the 1980s. Life cycle analyses, which investigate the resource use of a product from “cradle” to “grave,” only appeared in the 1990s. However, the benchmark for a sustainable bicycle stands in the room where I write this. It’s my 1980 Gazelle Champion road bike – now 43 years old. I bought it ten years ago in Barcelona from a tall German guy who was leaving the city. He had tears in his eyes when I walked away with it. I have a second road bike, a Mercier from 1978. That is my spare vehicle in case the other one breaks and I don’t have the time for immediate repairs. I have two more road bikes parked in Belgium, where I grew up and where I still travel a few times a year (by train, not by bike). These are a Plume Vainqueur from the late 1960s and a Ventura from the 1970s.

The main reason why I have opted for old bicycles is that they are much better than new bicycles. Most people don’t realize that, so they are also much cheaper. My four bikes cost me just 500 euros in total. That would buy me only one low-cost new road bike, and such a vehicle surely won’t last 40 to 50 years – as we shall see. Of course, it’s not just old road bikes which are better. The same goes for other types of bicycles built before the 1980s. I ride road bicycles because I cover relatively long distances, usually between 35 and 50 km round trip.

Image: The bicycle I use most often, a Gazelle Champion from 1980. It has covered at least 30,000 km since I bought it in 2013.
Image: The bicycle I use most often, a Gazelle Champion from 1980. It has covered at least 30,000 km since I bought it in 2013.
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What bicycles are made of

The first significant change in the bicycle manufacturing industry was the switch from steel to aluminium bicycles. Before the 1980s, virtually all bikes were made from steel. They had a steel frame, wheels, components and parts. Nowadays, most bicycle frames and wheels are built from aluminum. The same goes for many other bike parts. More recently, an increasing number of cycles have frames and wheels made from carbon fibre composites. Some bike frames are built from titanium or stainless steel. All of these materials are more energy intensive to produce than steel. Furthermore, while steel and aluminum can be recycled and repaired, composite fibres can only be downcycled and have poor repairability. 3

Several studies have compared the energy and carbon costs of bicycle frames and other components made from these different materials – which all have different strength-to-weight ratios. That research has some limitations. Scientists use crude methods because they lack detailed energy data from bike manufacturing processes, and some studies come from manufacturers who pay researchers to review the sustainability of their products. Nevertheless, all put together, the results are pretty consistent. For the sake of brevity, I focus on emissions (CO2 = CO2-equivalents) and ignore other environmental impacts.

Before the 1980s, virtually all bicycles were made from steel.

Reynolds, a British manufacturer known for its bicycle tubing, found that making a steel frame costs 17.5 kg CO2, while a titanium or stainless steel frame costs around 55 kg CO2 per frame – three times as much. 4 Starling Cycles, a rare producer of steel mountain bikes, concluded that a typical carbon frame uses 16 times more energy than a steel frame. 5 (That would be 280 kg CO2). An independent 2014 study – the first of its kind – calculated the footprint of an aluminum road bike frame with carbon fork from the “Specialized” brand and found the cost to be 2,380 kilowatt-hours of primary energy and over 250 kg of carbon – roughly 14 times that of a steel frame (without fork) as calculated by Reynolds. 2

A bicycle is more than a frame alone. Life cycle analyses of entire bikes show that the carbon footprint of all the other components is at least as large as that of a steel frame. 6 Scientists have calculated the lifetime carbon emissions of a steel bike at 35 kg CO2, compared to 212 kg CO2 for an aluminum bicycle. 78 The most detailed life cycle analysis sets the carbon footprint for an 18.4 kg aluminum bicycle at 200 kg CO2, including its spare parts, for a lifetime of 15,000 km. The main impact phase is the preparation of materials (74%; aluminum, stainless steel, rubber), followed by the maintenance phase (15.5% for 3.5 new sets of tires, six brake pads, one chain, and one cassette) and the assembly phase (5%). 9

Where & how bicycles are made

My steel bicycles date from a time when most industrialized countries had long-established domestic bicycle industries serving their national market. 3 These industries collapsed in Europe and North America following neoliberal globalization in the late 1970s. China opened to foreign investment and quickly became the largest bicycle manufacturer in the world. During the last two decades, China has made two-thirds of the world’s bicycles (60-70 million of 110 million annually). Most of the rest come from other Asian countries. Europe is back to producing ten million bikes annually, but the US only manufactures 60,000 bicycles per year. 3

Throughout the twentieth century, manufacturing bicycles required substantial inputs of human labor. 3 According to the Routledge Companion to Cycling, “wheels were spoked and trued manually; frames were built by hand; saddle making was laborious; headsets, gear clusters (blocks), brake cables and gears were physically bolted on.” Since the 2000s, automation has considerably reduced the need for human labor. The largest Chinese bike manufacturer, which builds one-fifth of the world’s bicycles, has 42 bicycle assembly lines making 55,000 bicycles a day – almost as much as the US in a year. 3

Domestic bicycles industries in Europe and North America collapsed following neoliberal globalization in the late 1970s.

The globalization and automation of the bicycle industry make bikes less sustainable. First, they introduce extra emissions for transportation (from raw materials, components, and bicycles) and for producing and operating robots and other machinery. Second, producing steel, aluminum, carbon fiber composites, and electricity is more energy and carbon-intensive in China and other bike-producing countries than in Europe and North America. 10 Most importantly, however, is that large-scale automated production represents sunk capital that needs to be working most of the time to spread overhead costs, driving overproduction. 3

How long bicycles last

How much energy and other resources it takes to build a bicycle and to deliver it to a cyclist is just half the story. At least as importantly is how long the bike lasts. The shorter its lifetime, the more vehicles need to be produced over the lifetime of a cyclist, and the higher the resource use becomes.

For a long life expectancy, some parts of a bicycle need replacement. These are typically smaller parts such as shifters, chains, and brakes. 11 Until a few decades ago, component compatibility was a hallmark of bicycle manufacturing. 12 My bicycles are a perfect example of this. Most components – such as wheels, gear set, and brakes – are interchangeable between the different frames, even though every vehicle is from another brand and year of construction. Component compatibility allows for easy maintenance and repairability, thereby increasing the lifetime of a bicycle. Bike shops in even the smallest villages can repair all types of bicycles using a limited set of tools and spare parts. 12 Cyclists can do minor repairs at home.

Unfortunately, compatibility is hardly a feature of bicycle manufacturing anymore. Manufacturers have introduced an increasing number of proprietary parts and keep changing standards, resulting in compatibility issues even for older bicycles of the same brand. 13 For example, if the shifter of a modern bike breaks after some years of use, a replacement part will probably no longer be available. You need to order a new set from a new generation, which will be incompatible with your front and rear derailleur – which you also need to replace. 12 For road bikes, the change from cassette bodies with ten sprockets (around 2010) to cassette bodies with eleven, twelve, and most recently thirteen sprockets have made many wheelsets obsolete, and the same goes for the rest of the drivetrain including shifters and chains. 121

Before the 1980s, most bicycle components were interchangeable between frames of different brands and generations.

Disc brakes, which are now on almost every new bicycle, all have different axle designs, meaning that every vehicle now requires proprietary spare parts. 1 Disc brakes also required new shifters, forks, framesets, cables, and wheels, making such bicycles incompatible with earlier designs. 12 The rise of proprietary parts makes it increasingly hard to keep a bike on the road through maintenance, reuse, and refurbishment. As the number of incompatible components grows, it becomes impossible for bike shops to have a complete stock of spare parts. 12

Component incompatibility is accompanied by decreasing component quality. An example is the saddle, which hardly ever outlasts a frameset because it cracks at the bottom of the shell. 12 A little extra material would make it last forever – as proven by all saddles of my 40 to 50-year-old road bikes. Low quality affects some parts of expensive bicycles but is especially problematic for cheap bicycles made entirely of low-quality components. Cheap bicycles – bike mechanics refer to them as “built-to-fail bikes” or “bike-shaped objects” – often have plastic parts that break easily and cannot be replaced or upgraded. These vehicles typically last only a few months. 1314

Illustration: Diego Marmolejo.
Illustration: Diego Marmolejo.
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How bicycles are powered

So far, we have only dealt with entirely human-powered bicycles, but bikes with electric motors are becoming increasingly popular. The number of e-bikes sold worldwide grew from 3.7 million in 2019 to 9.7 million in 2021 (10% of total bike sales and up to 40% in some countries like Germany). Electric bikes reinforce both trends that make bicycles less sustainable. On the one hand, electric motors and batteries require additional resources such as lithium, copper, and magnets, increasing the energy use and emissions of bike manufacturing. Researchers have calculated the greenhouse gas emissions caused by manufacturing an aluminum e-bike at 320 kg. 8 This compares to 212 kg for the production of an unassisted aluminum bicycle and 35 kg for an unassisted steel bicycle.

On the other hand, the life expectancy of an electric bicycle is shorter than that of an unassisted two-wheeler because it has more points of failure. The breakdown of the extra components – motor, battery, electronics – leads to a shorter lifecycle due to component incompatibility. An academic study on circularity in the bike manufacturing industry observes a significant increase in defective components compared to unassisted bicycles and concludes that “the great dynamics of the market due to regular innovations, product renewals, and the lack of spare parts for older models make the long-term use by customers much more difficult than for conventional bicycles.” 15

Electric bikes reinforce both trends that make bicycles less sustainable.

On top of this, electric bicycles require electricity for their operation, further increasing resource use and emissions. This impact is relatively small when compared to the manufacturing phase. After all, humans provide part of the power, and the electricity use of an electric bike (25 km/h) is only around 1 kilowatt-hour per 100 km. The average greenhouse gas emission intensity of electricity generation in Europe in 2019 was 275 gCO2/kWh. 16 If an e-bike lasts 15,000 km, charging the battery only adds 41 kg of CO2, compared to 320 kg for producing the (aluminum) bicycle. Even in the US and China, where the carbon intensity of the power grid is 50-100% higher than the European value, electric bicycle production dominates total emissions and energy use.

Cargo cycles

Combining energy-intensive materials, short lifetimes, and electric motor assistance can increase lifecycle emissions to surprising levels, especially for cargo cycles. These vehicles are larger and heavier than passenger bicycles and need more powerful motors and batteries. There are very few life cycle analyses of cargo cycles. However, a recent study calculated the lifecycle emissions of a carbon fiber electric cargo cycle to be 80 gCO2 per kilometer – only half those of an electric van (158 gCO2/km). 17 The researchers explain this by the difference in lifetime mileage – 34,000 km compared to 240,000 km for the van – and the carbon fiber composites in many components, including the chassis of the vehicle. The lifecycle emissions of the cargo cycle, including the electricity used to charge its battery, amount to 2,689 kg. That is almost 40 times the lifecycle emissions of two steel bicycles (each with a 15,000 km lifecycle mileage).

Extending the useful life of electric bicycles has less impact on lifecycle emissions when compared to unassisted bikes. That’s because the battery needs to be replaced every 3 to 4 years and the motor every ten years, which adds to the resource use of spare parts. 11 This is demonstrated by a life cycle analysis of an electric steel cargo cycle with an assumed life expectancy of 20 years. 18 During its lifetime, the vehicle uses five batteries (each weighing 8,5 kg), two motors, and 3.5 sets of tires. Most lifecycle emissions are caused by these spare parts, with the batteries alone accounting for 40% of the total emissions. In comparison, the emissions for the steel frame are almost insignificant. 18 This particular cargo cycle was built for African roads and is not entirely representative of the average cargo cycle, mainly because of its heavy tires.

Cargo cycles have another disadvantage. Passenger bicycles and cars usually carry only one person, meaning that one passenger kilometer on a bike roughly equals one passenger kilometer in an automobile. However, for cargo, the comparison of ton-kilometers is more complicated. If the load is relatively light – usually up to 150 kg – the electric cargo cycle will be less carbon-intensive than a van. However, heavier loads require several cargo cycles to replace one van, which multiplies the embodied emissions. 18 Switching to cargo cycles without significantly reducing the cargo volume is unlikely to save emissions. Obviously, cargo cycles with steel frames and without electric motors and batteries – for now still the majority – will have much lower carbon emissions over their lifetimes.

How bicycles are used

In recent years, many cities have introduced shared bicycle services. In theory, shared bicycles could lower the number of bikes produced and thus decrease the environmental impact of bicycle production. However, building and operating bike-sharing services adds significant energy use and emissions. Furthermore, shared bicycles don’t last as long as privately owned bicycles. Consequently, shared bike services further reinforce the trends that make bicycles less sustainable.

A 2021 study compares the environmental impact of shared and private bicycles while including the infrastructure that each option requires. It concludes that personal bikes are more sustainable than shared bicycles. 8 The research is based on the Vélib system in Paris, France, which has 19,000 vehicles, roughly half with an electric motor. Vehicle manufacturing and bike-sharing infrastructure cause more than 90% of emissions and energy use. The remaining emissions are due to the construction of cycle lanes (3.5%), the rebalancing of the bicycles to keep all stations optimally supplied (2%), and the electricity used for charging the batteries of the electric bikes (0.3%). Altogether, a shared bicycle from the Vélib system has an emissions rate of 32g CO2/km, which is three to ten times higher than the rate of a personal bike (between 3.5 gCO2/km for a steel bicycle and 10.5 g CO2/km for an aluminum bicycle. 8

Building and operating bike-sharing services adds significant energy use and emissions

The scientists found that the bike-sharing service led to a 15% drop in bike ownership. However, they also calculated that the average lifespan of a shared bicycle is only 14.7 months, with an average lifetime mileage of 12,250 km. In comparison, the average lifetime of a personal bike in France, based on a 2020 survey, is around 20,000 km – almost 50% higher than for shared bicycles. The Vélib system includes 14,000 bike-sharing stations with a total surface of 92,000 m2 and an estimated lifetime of ten years. Each of the 46,500 docks consists of 23 kg steel and 0.5 kg plastic. The power consumption of each bike-sharing station is around 6,000 kWh per year. Due to the high impact of the infrastructure, the lifecycle emissions of shared electric bikes are only 24% higher than those of shared non-electric vehicles. 8

The environmental footprint of bike-sharing systems can vary significantly between cities. A life cycle analysis of bike-sharing services in the US found carbon emissions of 65g CO2/km – twice as high as in Paris. 19 This is largely because the US systems rebalance the bicycles using diesel vans, while the French service employs electric tractors. The US study also looks at the newer generation of “dockless” bike-sharing services, which score even worse. Dockless shared bikes can be parked anywhere and located through a smartphone application. Although this removes the need for stations, each bicycle requires energy-intensive electronic components, and the system also generates emissions through communication networks. 1910 Furthermore, dockless systems require more bicycles and involve more rebalancing.

A life cycle analysis of Chinese bike-sharing services, many dockless systems, shows high damage rates and low maintenance rates for bicycles. The annual damage rate is 10-20% for reinforced bicycles and 20-40% for lighter vehicles which have become more common. In practice, a shared bicycle becomes scrap when the bike part with the worst durability breaks down. Repair is virtually not happening. 10 Finally, when the companies go bankrupt, bike sharing creates mountains of waste – including bicycles in good condition. 10 1

Image: Lifecycle carbon emissions per kilometre of riding a bicycle. Graph: Marie Verdeil. Data sources: [^8][^17][^19][^26].
Image: Lifecycle carbon emissions per kilometre of riding a bicycle. Graph: Marie Verdeil. Data sources: [^8][^17][^19][^26].
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Not every bicycle replaces a car

None of this should discourage cycling. Even the most unsustainable bicycles are significantly less unsustainable than cars. The carbon footprint for manufacturing a gasoline or diesel-powered car is between 6 tonnes (Citroen C1) and 35 tonnes (Land Rover Discovery). 20 Consequently, building one small automobile such as the C1 produces as many emissions as making 171 steel bicycles or 28 aluminum bicycles. Furthermore, cars also have a high carbon footprint for fuel use, while bikes are entirely or partly human-powered. 21 Electric cars have higher emissions for production but lower emissions for operation (although that depends entirely on the carbon intensity of the power grid).

The bicycle even holds its advantage when its much shorter lifetime mileage is taken into account. 22 Gasoline and diesel-powered cars now reach more than 300,000 km, double their lifetime in the 1960s and 1970s. 23 If a bicycle lasts 20,000 km, it would take 15 bikes to cover 300,000 km. If those are steel bicycles without an electric motor, the total carbon footprint for manufacturing is still six times lower than for a small car: 1,050 kg of CO2. If the bikes are made from aluminum and have electric motors, then emissions grow to 4,800 kg CO2, still below the manufacturing carbon footprint of the small car.

However, not every bicycle replaces a car. That is especially relevant for shared and electric bikes: studies show that they mainly substitute for more sustainable transport alternatives such as walking, using an unassisted or private bicycle, or traveling on the subway. 19 24 In Paris, shared bikes have three times higher emissions than electric public transportation. 8 In addition, many carbon-intensive bicycles are bought for recreation and are not meant to replace cars at all – they may even involve more car use as cyclists drive out of town for a trip in nature. In all those cases, emissions go up, not down.

How to make bicycles sustainable again?

In conclusion, there are several reasons why bicycles have become less sustainable: the switch from steel to aluminum and other more energy-intensive materials, the scaling up of the bicycle manufacturing industry, increasing incompatibility and decreasing quality of components, the growing success of electric bicycles, and the use of shared bike services. Most of these are not problematic in themselves. Rather, it’s the combination of trends that leads to significant differences with bicycles from earlier generations.

For example, based on data mentioned earlier, manufacturing an electric bicycle made from steel would have a carbon footprint of 143 kg. Although that is four times the emissions from an unassisted steel bicycle, it is below the carbon footprint of an aluminum bicycle without an electric motor (212 kg). Especially if the battery is charged with renewable energy, riding an electric bike can thus be more sustainable than riding one without a motor. Likewise, an aluminum bicycle with a long life expectancy – for example, through component compatibility – could have a lower carbon footprint than a steel bicycle with a more limited lifespan.

Many researchers advocate switching back to producing bicycles from steel instead of aluminium and other energy-intensive materials. That would bring significant gains in sustainability for a relatively low cost – slightly heavier bicycles. Steel frames would also make electric and shared bikes less carbon intensive. Some researchers promote bamboo bike frames, but the benefit compared to old-fashioned steel or even aluminium frames is unclear. 25 A “bamboo bicycle” still requires wheels and many other parts made out of metal or carbon fibre composites, and the frame tubes are usually held together by carbon fibre or metal parts. 6 Furthermore, the bamboo is chemically treated against decay and becomes non-biodegradable. 1

Reverting to local and less automated bike manufacturing is a requirement for sustainable bicycles.

Better component compatibility would increase the life expectancy of bicycles – also electric ones – through repair and refurbishment. It would bring no disadvantages for consumers, even on the contrary. However, unlike a switch to steel frames, better component compatibility would hurt the sales of new bicycles. A study concludes that “the abandonment of standardization is a profitable business model because it ensures that bicycles can only be ridden for so long.” 1 The decreasing sustainability of bikes is not a technological problem, and it’s not unique to bicycles. We also see it in manufacturing other products, such as computers. One bike mechanic observes: “The problem here is capitalism; it’s not the bikes.” 14

Reverting to local and less automated bike manufacturing is a requirement for sustainable bicycles. The main reason is not the extra energy use generated by transportation and machinery, which is relatively small. For example, shipping from China adds around 0.7 to 1.2 gCO2/km for shared bicycles. 8 More importantly, domestic and manual bike manufacturing is essential to make repair and refurbishment the more economically attractive option. By definition, repairing is local and manual, so it quickly becomes more expensive than producing a new vehicle in a large-scale, automated factory. 10 Locally made bicycles would increase the purchase price for consumers. However, better repairability would allow for a longer life expectancy and a lower cost in the long term. Addressing bike theft and parking problems is also essential because they are often a reason for buying cheap, short-lasting bicycles. 26

Finally, shared bicycle services can have their place, and we will probably see further improvements in their resource efficiency – the newest bike-sharing stations in Paris have reduced their power consumption by a factor of six. 8 However, shared bicycles are unlikely to become more sustainable than private bicycles because they always require rebalancing and a high-tech infrastructure to make the service work. Furthermore, getting attached to your bike can be a strong incentive to take care of it well and thus increase its life expectancy, as I can testify.

Reactions

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Reactions
Mark

Have a look at Roetz bikes in Amsterdam. They currently do rebuilt bikes from old frames. They’re also launching the Roetz Life [0] ebike. Stainless steel instead of aluminium. Their stated goal is to build a bicycle for life. Not affiliated with them in any way. [0] https://www.roetz.life/discover/

Christopher Rowe

Thank you for the lengthy, relatively well-sourced, and in-depth article on the carbon footprint of modern bicycles and bicycle culture. The author at least reveals his bias right up front with the completely unsupported claim: “The main reason why I have opted for old bicycles is that they are much better than new bicycles.” So at least we know what we’re in for.

But of most significance is that this piece is an example of a concept coincidentally known as bikeshedding. “Bikeshedding, also known as Parkinson’s law of triviality, describes our tendency to devote a disproportionate amount of our time to menial and trivial matters while leaving important matters unattended.”

Surely we have much more important matters to attend to before we start targeting bicycles.

Elisabeth

Hi Kris,

Fantastic article about bicycles - thank you! I really appreciate all the research you did.

I’m curious if you included the full lifecycle of emissions and the impacts of mining when measuring for instance eBikes relying on an electric grid that is fossil fuel powered vs. one that is “renewable” powered? E.g. the emissions and pollution lifecycle of solar panels, wind turbines, dams, etc.? I’m assuming you did not (since that adds huge complexity to the analysis) and stopped just at the “renewables” vs. fossil fuel type of grid. I’m also assuming you didn’t include the emissions required to mine the materials for the bikes and the batteries (for the electric ones). Anyway just curious how far back up the supply chain you went for all the pieces.

Thanks so much!!

Great work

Elisabeth

kris de decker

@ James

“First, the carbon emissions cited for frame manufacturer represent 0.1%-0.4% of the average Americans carbon footprint. This is such a negligibly small value. Why would you present these numbers and imply that the 3x multiplier is relevant without that critical context?”

–> Of course the 3x multiplier is important. It shows that bikes are becoming less sustainable. This is the only point the article makes. There are many things that represent 0.1%-0.4% of the average Americans footprint. Altogether they make a difference. A sustainable society will not arrive by categories. It can only happen by a more fundamental switch, one that solves the problem in all categories at the same time. And it’s not going to be a technological solution.

“Second, the section on cargo bikes. The author implies that cargo bikes are made in large part from carbon fiber. This is erroneous. Again, i build these things and not a single manufacturer uses carbon in any meaningful way.”

–> Sorry but carbon cargo bikes are for sale, for example: https://newatlas.com/bicycles/maniac-and-sane-carbon-fiber-cargo-bikes/

“Next is the issue of comparing to van emissions. I have no idea where this number comes from but it’s trivially disprovable.”

–> This number comes from this study [reference 17] Temporelli, Andrea, et al. “Last mile logistics life cycle assessment: a comparative analysis from diesel van to e-cargo bike.” Energies 15.20 (2022): 7817.. https://www.mdpi.com/1996-1073/15/20/7817

“Electric cargo bikes weigh in the neighborhood of 100kg, while trucks they replace weigh several multiples of that. Combining manufacturing and operations the overhead for combustion engines is obviously much larger.”

–> No it isn’t so obvious because the lifetime mileage of the cargo bike is much shorter (according to the authors of this scientific paper). But you misread the article: the comparison I cite is with an electric van, not a diesel van.

“My overwhelming emotion on reading this piece is sadness.”

–> Sorry to hear, but I don’t understand. Scientists are researching the sustainability of bike manufacturing. I report about the progress in the field. What is wrong with that? isn’t it worthwhile to know how we could produce sustainable bicycles?

JP

Great article.

The proprietary approach to part replacement for conventional bikes is a total nightmare…

Building on the comment from Mark about DRM – there is also a growing issue about barriers to replacing or repairing batteries on e-bikes.

We looked into this topic in the context of the EU Batteries Regulation which was finalised last year.

https://eeb.org/wp-content/uploads/2021/11/Battery-Report-2021.pdf see page 11-16

After interviewing independent bike battery refurbishment shops, they explained that even major bike battery brands like bosch and specialized were deliberately making battery maintenance challenging. With a few main issues: making the design of the battery pack impossible to service so that even small issues like water ingress (resulting in unnecessarily replacing the whole pack rather than replacing a small part); not selling replacement battery packs and changing designs (resulting in needing to replace the entire bike unnecessarily); and using software locks to prevent battery reset/cell replacement (resulting in the user replacing the whole pack unnecessarily).

Batteries packs probably shouldn’t be repaired by everybody, but they can be fixed by professionals, with the potential to save resources. The new EU law on batteries should make some of these practices illegal but we have millions of bikes on the market now with short lived batteries, and what about the rest of the world…

I agree with Christopher, that we should focus our efforts on other issues than the bike industry, but its clear that in many areas they are pursuing profit through consumerism and obsolescence, which sits terribly with the spirit of cycling or low tech… now cycling is gaining ground in our cities its important it remains the most credible and efficient way of getting around.

Thanks,

JP

Fabian

Thanks for this interesting read once again! As a former bike mechanic and someone, who helps in a self-help workshop on a voluntary basis these days, I can only confirm for observation that older bicycles are often more „rugged“. When I was working in a bike shop until about 15 years ago, older bikes often had repairs like flats, worn-out tires, rusted cables or brake pads needing replacement.

That being said, we also need to consider that these older bikes where mostly used for commuting or occasional recreation, whereas newer bikes like e.g. mountain bikes and trekking bikes where often also used under much worse conditions, so it should not come as a surprise, that broken rear derailleurs, cranks and pedals where often the results of accidents and severe bike abuse from people shredding down the mountains. But talking about the sustainability of the mountain-biking-industrial-complex is probably a topic for another article. ;-)

My personal sweet spot for bicycle components are the mid-90s till the early 2000s – not for frames, since these where already mostly made of aluminum. Thanks to the influence of mountainbikes, city and trekking bikes adopted much lower gears, which makes them way more usable for commuting in hilly terrain than older bikes. Braking technology also has improved quite a lot, which is – again – much more important when you life in the mountains. And let’s not forget about lighting, which has finally become really reliable and efficient thanks to the mass-adoption of dynamo hubs, which also work in wet conditions. Most bikes used pretty standardised components during that era (e.g. 100/135 mm hub spacing with quick release axles, 68 mm English threaded bottom braked, JIS square taper cranks, v-brakes) and where quite versatile. For example, many entry-level MTBs also came with rack mounts, so they could be re-purposed as commuter bikes.

Having a steel frame with equipped with a SON dynamo hub paired with a Rohloff Speedhub (internal gear hub with 14 speeds) gives you a very versatile bicycle that can survive similar distances to a modern car but requires very little maintenance. That combination has been the go-to setup for many world travellers for many years. Only downside is, that these are very high-end-components which are expensive and hard to protect against thievery when you need to lockup your bike in town. On the other hand, the price of these components does not come out of nowhere and they probably use-up more recourses than cheaper parts e.g. from Shimano. If we consider that, we probably should not equip all bicycles in the world with the very-best components in existence to make them more sustainable (wich is also unrealistic because both hubs are made by relatively small companies).

If you want a cheap, versatile and reliable machine, look for early 90s mountain bikes – they often come with rack and fender mounts and feature very sturdy steel frames. Be sure to grab one that does not already have a suspension fork, because these will need maintenance at some point and spare parts might be hard to get for these old models. Old MTBs can often be found on classifieds very little money and are also pretty easy to maintain and customise to fit your own needs. And the latter point might be the most important. Once you put some effort into any artefact, you’ll become more emotionally attached to it and won’t let that thing go or throw it away without thinking twice.

Igor

Thank you for the detailed article. My 2 cents:

Aluminium has a large carbon footprint mostly because smelting uses enormous amounts of electricity. So enormous that smelters are often placed next to a powerplant producing cheap power - which these days usually means coal (or even worse, lignite/brown coal). But at least in theory it could be a renewable plant. Another, much smaller source of CO2 emissions are carbon anodes used in smelting which slowly burn in the process, but other materials are being tested. Aluminium is also recycled quite effectively, so overall effect might be smaller than calculated here.

I think the main issue isn’t the life expectancy of a bicycle frame, but rather of components such as chains, gears, tyres, cables etc. Of course they are replaceable, but if you neglected the maintenance for a few years or returned from a long journey, you will find out that just buying all the parts will cost you more than a new bicycle (even disregarding the labor cost or possible compatibility problems). It should be trivial to manufacture more reliable components, there’s no reason why a bicycle gear wears out after five thousand kilometers despite transmitting barely 100W of power if a similar gear in the car, connected to a 100kW engine, never needs replacement during 500 000 km lifespan.

Igor

Mario Stoltz

@Kris, thank you so much for the great article. I love the diversity of topics on your website. In this particular case, I would suspect you picked up the topic because it really matters to you personally :-)

Not that I would have numerical evidence, but I suspect part of the effects you describe can also be attributed to scale effects, meaning the total number of bikes produced, and the boundary conditions under which the players in the value chain are operating.

In a globalized capitalist economic system, manufacturers are not incentivized to produce long-lived, sustainable, repairable products unless they see a need to do so, i.e. either if there is a tangible market for such products, or if there is external regulation (with either subventions or penalties) that forces them to go that way.

In the absence of such incentives, they will produce what optimizes their economic result. Still, that includes the automatic regulation towards the bottom end: if the product becomes so bad that nobody buys it, the manufacturer will increase quality.

However, there is also a social dimension: less wealthy people may not be able to afford buying a good, let alone a sustainable bike. They certainly lack the money to buy them new, and they may lack the time and resources to buy them used and repair them for use.

I guess this calls for a strengthening of local repair and self-help initiatives, as well as for local used-bike markets, to help give all parts of society access to decent-quality individual mobility.

D. Wick

Bicycle mechanic Mac Liman has started a petition asking bicycle manufacturers to stop producing low-quality, unrepairable bicycles. Here are a couple of articles about it:

https://pirg.org/articles/the-bikes-that-last-4-months/

https://cyclingmagazine.ca/sections/news/mechanics-start-petition-calling-for-end-of-built-to-fail-bikes/

And the petition itself: https://docs.google.com/forms/d/e/1FAIpQLSf6dcfFQFqE6CmLxm02taF7SpTBEPG2Jq8cJBTOVebbX5L1EA/viewform

It isn’t just a sustainability problem, it is also an equity problem. These are the bikes that people buy when they need something “affordable”, not realizing that the bike will end up broken and useless in a matter of months.

Mnt_dude

Step one: Use local labor so you don’t have to plow a big dirty boat across an ocean everytime.

Lawrence

Reducing bicylcle weight has always been a goal of enthusiasts. But saving 2 kilos on a 16 kilo bicycle is not a 12.5% savings. That is because the weight of the rider must be included. If a rider weighs 60 kilos, the 2 kilos only represents 2.6% weight savings – hardly worth the cost of the lighter bike. Also going on a diet to save those two kilos would acheive the same effect at much less cost in money as well as to the environment.

Donna Berry

I use vintage sewing machines (both electric and hand/for powered) because they are more durable and reliable than modern ones. I wonder if anyone has analyzed the energy cost of manufacturing sewing machines from—before 1970 till now?

Keep up the good work!

Donna Berry

Carol

Thanks for all this great information, and your personal comments about biking brought a smile to my face, several times.

Carol

Dr. Coyote

Thanks for the in-depth article. And you’re correct, planned parts

obsolescence is the bane of bicycle longevity. I’m suffering through

the end-of-life cycle for several decade-old bikes, where simply

finding (say) chainrings and replacement wheels has become more

time-consuming than actually installing the new parts.

Dr. Coyote

Andrew D

Some interesting ideas expressed here, but no means of acting on them. By what mechanism would a shift away from manufacturing most bikes in Asia towards manufacturing in local economies occur?

Also, in your rush towards ‘steel is better than aluminium’, you either don’t know or don’t understand that many of the components on your Gazelle bike are aluminium: the wheels, the cranks, the handlebars. Before 1980 most bicycle FRAMES were made from steel, but components and higher-quality wheels had been aluminium for many decades. There are also a lot of half-truths in your assertions about the current state of the bicycle industry and the availability of parts (which is actually excellent from all major manufacturers). I’m no fan of the bike industry’s proliferation of new standards, but it might also be true that a wider range of types of bicycles being available might lead to a wider uptake of cycling.

Anyway, I think your commenter earlier who said we have much bigger concerns in the sustainability field than this is 100% correct. Yes, if more bikes had steel frames we would be more sustainable. But the net benefit of people cycling instead of driving outweighs the dubious sustainability of carbon framed bikes every day of the week.

More people on bikes is what we want. Your thesis is unlikely to assist in this.

Nico

I would be interested in looking at how the carbon emissions from medical system plays into the equation considering your previous article. The health benefits from biking could substantially reduce carbon emissions produced by the medical industry by avoiding many complications associated with inactivity.

James

Backing up @Andrew here. I’m a bike manufacturer and this piece seriously disappoints me. I build steel frame ebikes with upcycled batteries which directly replace two stroke motors in emerging markets. This article, while it contains citations lacks context. I’m very disappointed that the author, a cyclist, would make the perfect the enemy of the good.

First, the carbon emissions cited for frame manufacturer represent 0.1%-0.4% of the average Americans carbon footprint. This is such a negligibly small value. Why would you present these numbers and imply that the 3x multiplier is relevant without that critical context?

Second, the section on cargo bikes. The author implies that cargo bikes are made in large part from carbon fiber. This is erroneous. Again, i build these things and not a single manufacturer uses carbon in any meaningful way. Next is the issue of comparing to van emissions. I have no idea where this number comes from but it’s trivially disprovable. Electric cargo bikes weigh in the neighborhood of 100kg, while trucks they replace weigh several multiples of that. Combining manufacturing and operations the overhead for combustion engines is obviously much larger.

This section closes with an offhand comparison to Chinese wheelbarrows and traditional steel bikes. Cargo bikes disproportionately replace cars and trucks and this comparison is so wildly ungrounded in reality. To change the world you must think seriously about the current one.

There are other issues, but I’m closing on this one. I love steel. I ride steel bikes every day and have never owned a bike of a different material. My overwhelming emotion on reading this piece is sadness. There are many of us out here fighting to make pragmatic shifts in society and making forward progress. The next time the author pens a piece like this, I hope they take the time to put numbers in context honestly and aren’t afraid of the conclusion that we’re going in the right direction and that it will take all of us to get there.

Pau Luque

Thank you for your article! I believe any discussion about the subject is positive, making us rethink our individual and collective practices. I would like to add something regarding shared bike services: a different approach to their concept may improve their footprint, and we can tackle it considering the disadvantages presented in your article: rebalancing and high-tech infrastructure. For example, in my city there is a shared bike service for people that come from neighboring towns by bus. They address to a specific counter and write their name in a logbook, receiving the lock key for a bike. They can use it all day and return it to the bus station before it closes at night.

Paul

Great article. 3 comments:

First, I agree completely regarding intercompatibility. As an example, I recently built-up a new mountain bike on a donated frame, and the number of choices/options is bewildering. Here are some of the choice problems I ran into: (i) 29" vs. 26" vs. 27.5" wheels. Tires regular or tubeless. (ii) Hydraulic vs. cable disc brakes, different rotor sizes, different attachment methods of rotor to the hub. (iii) Shimano Hyperglide cassette hubs come in two sizes, and you need correct hub for the cassette size you choose. Derailleur cage (long vs. short) also needs to be sized appropriately for the largest sprocket. (iv) Headsets on many new MTBs are now tapered (wider at bottom). It is becoming increasingly hard to find decent suspension forks compatible with straight 1-1/8" steer-tube frames. (v) There are several different dropout dimensions for front and rear. This impacts choice of hubs, forks, quick-release levers, etc. (vi) Several bottom-bracket standards, each of which only fits certain types of cranks. (vii) Handlebar clamps and stems are now available in several diameters. Buying a new bar can require replacing the stem. (ix) Seatpost diameters are all over the place. Often need shims or spacers to make it fit. Also seatpost clamp designs not compatible with all saddles - many have a bolt in the top, only accessible if the saddle has a hole in the middle.

This is just for mountain bikes, so imagine the same all over again for road bikes and e-bikes, not to mention the many single-use tools needed for these proprietary things to actually be fitted on the bike. Often-times, individual components will not play nice together (e.g., Shimano shifters and Tektro brake levers), requiring liberal use of the Dremel to make things fit properly.

Second, your estimates of lifetimes for common components are very conservative. If you live anywhere with cold weather and cycle in the winter, the use of road salt is very bad for bike parts! I’ve resigned myself to having to replace the chain at least once a year (usually in the spring), and have already gone through 3 cassettes in 10 years on one of my bikes. Cables are another example - despite keeping them well lubricated, they usually need replacing every couple of years.

Third, a theoretical advantage of e-bikes is they allow the use of slightly heavier and more"beefy" components that would otherwise be too heavy for use on a regular analog bike. I don’t see the components on current e-bikes as being built any better than regular bikes, but it would be nice to imagine a future where e-bike components (cables, chains, etc.) were built to a similar degree as seen in motorcycles, designed to last several years before needing replacement. The extra weight is less of an issue if the work of hauling it around is offloaded to the electric motor!

tensaimon

I ride Surly bikes (Pack Rat, bought new, for pavement/commuting, and a Pugsley, bought used, for off road exploring (including beaches)) because they are steel with good “parts bin” compatibility (standard parts). I’m a novice mechanic tho so I’m still learning how to make it all fit together.

In particular, I’m developing the Pugsley as my “apocalypse bike” that, with a switch of tires/wheels and handlebars, will be able to handle anything from long road miles to the beach. Hopefully that’ll be my “one bike to rule them all” though I’ll keep the Pack Rat for commuting - as Kris says it’s great to have a backup bike in case of mechanical issues (especially when I need a bike to commute).

You might find pathlesspedalled on youtube interesting - he’s recently been switching over to friction shifters on his bikes because then he can pretty much freely mix and match derailleurs, chainsets and shifters. https://www.youtube.com/watch?v=y8CwNO-2RIg

(I’m slowly working my way thru his recommendations - waxed chains, genevalle shifters, hot-swappable handlebars….)

Finally, whilst I understand the commenters who are concerned that we have bigger fish to fry than bicycle manufacture (any bicycle is better than a car), I agree with Kris that everything should be examined from a sustainability standpoint, and in particular it’s very important to understand how profit-pursuing capitalism is making a very sustainable transport option less so (whilst frustrating the hell out of consumers, shop-owners and mechanics…including me…)

tensaimon

PS I’ve tried electric, and might add an aftermarket kit to my pugsley for maximum versatility (bafang or tongshen), though I have also decided that building my leg muscles (both thru cycling and barbell weights) is a viable (tho admittedly not equal: a motor is always going to be stronger than my legs) alternative approach: low maintenance, no replacement parts (I’m only 48, decades from knee replacements….I hope!), no batteries required….

Benoît

I might have a bought a Hagen cargo instead of a Bullitt if I had read this article before…even in my Hilly town

Bartlomiej

Great article (as always).

The regulation issues touched on in some of the comments are a major issue in taking control of transportation production. I wonder if you ever pondered the subject of DIY motorvehicles in this context.

In many countries’ traffic code there’s a category of a slow moving vehicle which imposes much less restrictions concerning homologation etc. (I imagine a DIY solar-powered AI-driven slow-moving microcamper, but that’s not very lowtech.)

And as to steel frames, I wonder what you think about N55’s spaceframe vehicles made of aluminium, which I always found a bit absurd, although fascinating.

alex

I second with several comments here. The part on cargo bikes is mainly based on a single study, that is based on one single example of bike, based on questionnable hypothesis. Your article implies that there is carbon in cargo bikes, in general. That is a false statement. Andrew said it, and he is right. According to this link, the manufacturer of the cargo bike in the study you cite, made less than 100.000€ of sales last year…(https://www.startuplus.it/startup/one-less-van-srl/). I’m not sure it’s a good example to draw a picture of an entire industry.

You could have looked at HarryVSLarry’s Bullitt, which have partnerships with DHL for packet delivery in Germany: No carbon on their bikes. The battery weighs 2.5 to 3.5kg (Shimano), not 8.5kg. You could have looked at Douze, that partnered with Toyota for manufacturing (Aluminum injection process) and sales. Well, no carbon in these frames either. Here as well, the battery is not anywhere near 8.5kg. You could have cited Riese&Muller, well known for their bikes in Germany. No Carbon on any of their cargo models. Even the double battery option does not reach 8.5kg of embedded battery…

Interestingly enough, that same study you cite suggests a battery life longer than 10 years (in paragraph 4.1) when you write that the battery needs to be replaced every 3 to 4 years… Why use this specific study for many numbers, but not for estimated battery life ?

It looks to me that you cheery picked. What was your intent ? I don’t know. But I fully agree with those who commented here. Your paragraph about cargo bikes seems stuffed with outdated or erroneous information. It’s disappointing. I was just arriving on Low-Tech Magazine. Now I know I should take articles and analysis with a grain of salt.

kris de decker

@ alex

I was not cherry picking. I have simply cited the very few LCA’s of cargo cycles that exist, and none of these is representative of the typical cargo cycle. If you know of any life cycle analysis of the cargo cycles you mention, please let me know. If there is no study, I cannot cite it.

My article is clearly supporting the use of steel for bicycles, and of course this includes cargo cycles. Obviously, the bikes you mention are therefore much more sustainable. Read the first sentence of that paragraph: “Combining energy-intensive materials, short lifetimes, and electric motor assistance can increase lifecycle emissions to surprising levels, especially for cargo cycles.”

I have no intention of discouraging the use of cargo cycles, or bicycles in general. The problem that this article addresses is that a lot of unsustainable trends are combined, and this logically leads to the highest carbon footprints in cargo cycles, because they are heavier.

By the way, carbon cargo cycles may be not typical now, but let’s talk in another 10 years. Carbon road cycles are relatively new, too, and they have become the norm. The carbon cycle I cite is not the only one on the market.

I made a few edits to the paragraphs to address your and others’ concerns. Hope this makes things more clear.

kris de decker

@ alex

Forgot your other point: “Interestingly enough, that same study you cite suggests a battery life longer than 10 years (in paragraph 4.1) when you write that the battery needs to be replaced every 3 to 4 years…” Why use this specific study for many numbers, but not for estimated battery life ?

Most of all because 10 years is not a realistic life expectancy for a battery, and most other studies put it at 3 to 4 years (see the other references). Also note that if those scientists had used a more realistic number the carbon emissions of the cargo cycle would further increase.

Greg B

Bikes are clearly a greener alternative to ICE or even EVs. But the comparison table should include the metabolic greenhouse contribution per km, assuming the ICE comparison includes fuel. The average diet incurs a footprint of around 5 Kg of CO2 for every 1000 KCals consumed to produce and distribute the food. Assume biking demands an extra 100 kCals to go 50 km, that adds 10 gms per km to the footprint.

Heidi

Here in Canada (Montreal, with hills) and getting older, I bought an ebike the other year in order to continue commuting to work. It’s saddening to read that planned obsolescence is likely to require that I purchase another ebike before I retire in a few years. I’m hoping to get away with only buying a second battery.

You are comparing (in most cases) bikes to bikes, and finding that older bikes are better. I am not so sure about that. My 2000 Norco Bushpilot was a workhorse, but the mid 90’s Norco road bike crashed and burned under me when I tried to cross a highway from a standstill. OK, that was components rather than frame, but a frame that lasts forever without components will still not go very far. What we need is an extension of right to repair legislation from electronics and appliances to bikes. We also need to be able to upgrade things like batteries, and someone needs to invent a battery that is happy in cold weather like our winters. The chap that argued batteries can last for 10 years hasn’t tried to use one in the winter in Montreal. I have lost range in just the year and half that I have been riding.

Sustainable bikes are going to have to come with an affordable price of admission, and many of the alternative mentioned in both your article and the comments here do not. Somehow we need both economies of scale and shorter logistics chains in order to address the lifespan of bikes in the real world.

Just my $0.02

Andrew

This is an ambitious article!

I understand you’d broadly like to see a return to domestic and manual manufacturing for bicycle components and bicycles.

In particular, you first suggest that local and small manufacture of parts and bicycles would improve repairability. I don’t know that this is true. I can only speak for the US, but here there certainly are small companies building bikes and components in the way you desire– for example Paul’s Components– but they generally don’t seriously offer parts for repair any more than shimano or SRAM. Furthermore, bicycle shops generally don’t struggle to repair even 30 year old bikes, almost all of which use foreign made mass-manufactured components.

You also suggest that better repairability from local manufacture would extend bicycle longevity and reduce amortized costs over bicycle lifespan. I also don’t know that this is true, bicycle parts suffer from heavy wear due to lots of exposed parts, and components like bearings simply need replacement once dirt abrades their races. Furthermore, while locally built frames are available today, (with just a few with vaguely internationally-competitive prices), locally built boutique components are dramatically more expensive than the offerings by shimano or SRAM. By almost anybody’s calculation, the most affordable way to own and operate a bicycle per kilometer remains to purchase a Taiwanese factory-built bicycle with low-to-mid tier factory-built shimano components.

Lastly, there’s also your seemingly unsubstantiated claim that local and manual manufacture would be more sustainable. I couldn’t find any academic literature suggesting that this is true, there’s just too much variation by industry to make such a statement. Furthermore, large manufacturers such as Trek and Shimano do publish sustainability reports, but smaller companies do not.

To summarize my observations on the above points, the typical cottage-industry locally-manufactured bicycle you evangelize does already exist, but is incredibly, unaffordably expensive and doesn’t generally offer longevity benefits over conventionally built bicycles.

As an aside, I suspect bicycle sustainability has more to do with technology choice and market. The exposed nature of derailleur and chain based bicycle drivetrains means that they’re consumed extremely rapidly, offering advantages only in weight and efficiency. There are some companies offering sealed gearboxes that can be used with belt drives which offer much greater longevity (some getting 30,000km of use), with some products such as the Rohloff hub suspected to have human lifespan. Bearings, tires, and braking surfaces will always need replacement but these are available technologies available right now that offer longevity advantages. These products are almost exclusively enjoyed by cyclists who ride a ton of miles, but they remain unaffordable to more casual riders because the production volumes remain low.

Foldi-One

Seems like you are willing to take some very worst case scenarios and assumption in your references and paint them as more universal - for instance the cargo bike section where the paper is guessing about lifespan with remote and rugged use in Africa not somewhere with real roads. You really should get way way more than 3-4 years out of a battery, even with heavy use. At least assuming the battery cut off and charge/discharge rates are kept sensible I’d suggest at least 5-6 years would be more reasonable and anything putting less cycles on the battery than a really heavy user should be limited by the shelf-life more than likely, so 10-15 years is more reasonable expectation. The brushless style motors aught to last as long as the frame with minimal care if they are not being abused by the conditions - bearing replacements are likely but not the whole motor.

You also never compare the expected lifespan for a frame really, regular steel is fine and cheaper but it rusts… Aluminium, the composites and Stainless shouldn’t just degrade badly, so assuming you can replace the consumable wear parts it doesn’t matter if they cost more to produce upfront - you won’t need another unless it is in a pretty serious accident.

Regular steel is also going to tend to a much heavier frame - there isn’t even a mention on how that increases the energy required to use that bike, which matters. It will even matter alot over the bikes lifetime if the users are putting in the miles - food ain’t CO2 free. There is a reason bikes have gotten lighter as it became affordable to make them so - it makes the bike easier to ride. And that is far more important than a relatively small differential in upfront CO2 costs, as people won’t use them at all especially in hilly areas if they are so heavy it kills you trying to get them moving.

Andrew

@Greg:

Thank you for bringing up the environmental cost of food when considering life cycle sustainability. Obviously, such calculations aren’t well defined, with some studies ignoring food and some including it. However, from what I can see, the ECF’s sustainability report0 is often considered as the academic consensus in this field, and they do include food. Because of this, they find that e-bikes and conventional bikes have nearly identical costs/km, 22 and 21 g CO2/km, respectively. The ECF also has a useful page1 on other facts and figures on bicycling, which you and others may find useful.

@ Foldi-One I like your holistic thinking on aluminum frames, but aluminum does have material properties which could limit the long-term longevity of bicycle frames. In particular, because bicycle frames experience cyclic loading, fatigue becomes important to consider. I’ll defer to this Quora post which discusses the phenomenon2: “Steel will fatigue just like aluminum, to a point, then you hit the endurance limit. At that loading or less, steel is essentially free of fatigue effects no matter how many cycles are applied. Aluminum has no similar “endurance limit” and continues to fatigue even at much lower loading driven by the number of load cycles.”

Ultimately, I’m just being pedantic and I share your belief that it’s important that bikes are built so people enjoy riding them, rather than policing their sustainability to an absurd standard. When riding a bicycle is 10x more sustainable per km than driving a car, it’s obviously much more important that bicycles are built for enjoyment than sustainability. By way of example, a policy banning Aluminum as a frame material could diminish (optimistically) 10% of bicycle ridership but (optimistically) double the lifespan of a bike frame. Holistically, the population level energy use becomes .110 + .9.5 = 1.45 times the original– so what sounds like a nice, environmentally conscious policy is actually quite disastrous.

dik

dear kris x no car. steel frame + shimano i maintain a beautiful late ’90s road bike. lately mostly ride it to a supermarket. hilly demanding 15 miles round trip. in the spirit of bastiat … “Despite the intuitive sense that electric bikes would require more resources than regular bikes, life-cycle analysis shows that they actually consume 2-4 times less primary energy than human riders eating a conventional diet. This conclusion is largely due to the considerable amount of transportation and processing energy that is associated with our western food system.”

HERE: http://www.electric-bikes.com/betterbikes/Ebike_Energy.pdf

am luddite 4 sure don’t want an e-bike. perhaps should spend more time gardening? love the work of u! dik

madf

The best material for a bicycle is …. not the steel: THE TITANIUM. a titanium frame can last a life or even more because it doesn´t have rust problems and except in case of accident, the material will matain fresh for all his life. Secon aluminium, specially in wet areas like UK, but the fatigue of the material after 40 years or more is noticeable an d can crack. Steel … rust. But can be repairable (Paul brodie does with 80´s and 90s frames, why not more shops do that? )

Carbon fibre … a waste of energy. Not reciclable yet and not the best for daily use. Lot of scarfs and chips etc I don´t like it.

The bes choice for daily use and 20-30 year of minimun life: Aluminium mid range bicycle. For a entusiast: Titanium, it will last for ever. But only if you know what you whant, if you chage a lot it is useless this article, but has resale value and people still like titanium frames, specially good ones so it will be in other hands for many decades.

Gregory

@ Mark

Hello Mark, With regard to the European text, I read on an obligation for manufacturers not to block the way to other manufacturers of spare parts (article 57). Did I miss something? Could you point out which part of the text is causing the problem? Thank you so much, Gregory

Nikolaj Mosch

We presented our circular bike concept at Eurobike in Frankfurt. We combine your assumption and a modern ecological interpretation of some other ideas. We had an upcycling project for four years. Most modern parts failed, some won. Please have a look if you have any idea of a cooperation: www.moschbikes.de .


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  19. Luo, Hao, et al. “Comparative life cycle assessment of station-based and dock-less bike sharing systems.” Resources, Conservation and Recycling 146 (2019): 180-189. https://www.sciencedirect.com/science/article/abs/pii/S0921344919301090 ↩︎ ↩︎ ↩︎

  20. https://www.theguardian.com/environment/green-living-blog/2010/sep/23/carbon-footprint-new-car ↩︎

  21. Bicycles are entirely or partly powered by food calories. Some people argue that the life cycle energy requirements of bicycles are higher than other modes, when one considers the impact of food require to provide additional calories that are burned during the bicycle use. However, the majority of people in car-centered societies take in more calories than their sedentary lifestyle requires. Increased cycling would lead to lower obesity rates, not to higher calorie intakes. ↩︎

  22. This a purely theoretical calculation, because cars encourage much longer trips than bicycles. ↩︎

  23. Ford, Dexter. “As Cars Are Kept Longer, 200,000 Is New 100,000.” New York Times, March 16, 2012. https://www.nytimes.com/2012/03/18/automobiles/as-cars-are-kept-longer-200000-is-new-100000.html?_r=2&ref=business&pagewanted=all& ↩︎

  24. Zheng, Fanying, et al. “Is bicycle sharing an environmental practice? Evidence from a life cycle assessment based on behavioral surveys.” Sustainability 11.6 (2019): 1550. https://www.mdpi.com/2071-1050/11/6/1550 ↩︎

  25. A comparison of the life cycle emissions of a bamboo versus an aluminium bicycle showed little difference (233 vs. 238 kg CO2). [6] ↩︎

  26. Larsen, Jonas, and Mathilde Dissing Christensen. “The unstable lives of bicycles: the ‘unbecoming’of design objects.” Environment and Planning A: Economy and Space 47.4 (2015): 922-938. https://orca.cardiff.ac.uk/id/eprint/131212/1/M%20Christensen%202015%20the%20unstable%20lives%20of%20bicycles%20ver2%20postprint.pdf ↩︎