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.
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
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.
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. A recent study calculated the lifecycle emissions per kilometer to be 80 gCO2 – 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 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
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. Cargo cycles also have less carbon-intensive alternatives, such as hand carts. In terms of emissions, a Chinese wheelbarrow beats any delivery van by a large margin, even when measured in ton-kilometers.
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. 101
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. 1924 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. 27 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. 25
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.
Kris De Decker
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Johnson, Rebecca, Alice Kodama, and Regina Willensky. "The complete impact of bicycle use: analyzing the environmental impact and initiative of the bicycle industry." (2014). https://dukespace.lib.duke.edu/dspace/bitstream/handle/10161/8483/Duke_MP_Published.pdf ↩↩
Norcliffe, Glen, et al., eds. Routledge Companion to Cycling. Taylor & Francis, 2022. https://www.routledge.com/Routledge-Companion-to-Cycling/Norcliffe-Brogan-Cox-Gao-Hadland-Hanlon-Jones-Oddy-Vivanco/p/book/9781003142041 ↩↩↩↩↩↩↩
Cole, Emma. “What’s the environmental impact of a steel bicycle frame?” Cyclist, November 7, 2022. https://www.cyclist.co.uk/in-depth/11003/steel-bike-frame-environmental-impact ↩
Mercer, Liam. “Starling Cycles publishes environmental footprint assessment and policy.” Off-road.cc, July 2022. https://off.road.cc/content/news/starling-cycles-publishes-environmental-footprint-assessment-and-policy-10513 ↩
Chang, Ya-Ju, Erwin M. Schau, and Matthias Finkbeiner. "Application of life cycle sustainability assessment to the bamboo and aluminum bicycle in surveying social risks of developing countries." 2nd World Sustainability Forum, Web Conference. 2012. https://sciforum.net/manuscripts/953/original.pdf ↩↩
Chen, Jingrui, et al. "Life cycle carbon dioxide emissions of bike sharing in China: Production, operation, and recycling." Resources, Conservation and Recycling 162 (2020): 105011. https://www.sciencedirect.com/science/article/abs/pii/S0921344920303281 ↩
De Bortoli, Anne. "Environmental performance of shared micromobility and personal alternatives using integrated modal LCA." Transportation Research Part D: Transport and Environment 93 (2021): 102743. https://www.sciencedirect.com/science/article/abs/pii/S136192092100047X ↩↩↩↩↩↩↩↩↩↩
Roy, Papon, Md Danesh Miah, and Md Tasneem Zafar. "Environmental impacts of bicycle production in Bangladesh: a cradle-to-grave life cycle assessment approach." SN Applied Sciences 1 (2019): 1-16. https://link.springer.com/article/10.1007/s42452-019-0721-z ↩
Mao, Guozhu, et al. "How can bicycle-sharing have a sustainable future? A research based on life cycle assessment." Journal of Cleaner Production 282 (2021): 125081. https://www.sciencedirect.com/science/article/abs/pii/S0959652620351258 ↩↩↩↩↩
Leuenberger, Marianne, and Rolf Frischknecht. "Life cycle assessment of two wheel vehicles." ESU-Services Ltd.: Uster, Switzerland (2010). https://treeze.ch/fileadmin/user_upload/downloads/Publications/Case_Studies/Mobility/leuenberger-2010-TwoWheelVehicles.pdf ↩↩
Erik Bronsvoort & Matthijs Gerrits. “From marginal gains to a circular revolution”. Paperback (full-colour): 160 pages, ISBN: 978-94-92004-93-2, Warden Press, Amsterdam. https://circularcycling.nl/product/from-marginal-gains-to-a-circular-revolution/ ↩↩↩↩↩↩↩
US petition that calls for end o built to fail bikes gaining support in BC. https://vancouversun.com/news/local-news/u-s-petition-that-calls-for-end-of-built-to-fail-bikes-gaining-support-in-b-c ↩
Aaron Gordon. “Mechanics Ask Walmart, Major Bike Manufacturers to Stop Making and Selling ‘Built-to-Fail’ Bikes”, Vice, January 13, 2022. https://www.vice.com/en/article/wxdgq9/mechanics-ask-walmart-major-bike-manufacturers-to-stop-making-and-selling-built-to-fail-bikes ↩↩
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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. ↩
This a purely theoretical calculation, because cars encourage much longer trips than bicycles. ↩
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& ↩
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 ↩
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 ↩
Calão, Júlio, et al. "Life Cycle Thinking Approach Applied to a Novel Micromobility Vehicle." Transportation Research Record 2676.8 (2022): 514-529. https://journals.sagepub.com/doi/pdf/10.1177/03611981221084692 ↩
A comparison of the life cycle emissions of a bamboo versus an aluminium bicycle showed little difference (233 vs. 238 kg CO2).  ↩
You haven't even mentioned two other issues: legal red tape and DRM.
Legislation. Have a look into the EU-level L1e-b directive 168/2013. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A32013R0168 . Most speed pedelec parts cannot legally be replaced except with the blessing of the speed pedelec manufacturer. See https://d1wa5qhtul915h.cloudfront.net/app/uploads/2018/01/Guidelines-for-the-parts-replacement-of-speed-e-bikes-pedelecs-up-to-a-pedal-assist-of-45-km.pdf . An extra battery for example, to extend your reach? Not allowed. https://leva-eu.com/ is a small trade association organisation that seems to try and tackle this mess.
DRM. Look at the electric drive ecosystem for speed pedelecs. Almost all bicycle and drive system manufacturers are very much into DRM. Forget about recelling most recent battery packs. Try to get a battery replaced with another one, or an engine with another one, or a sensor with another one, except with manufacturer blessing. Bosch is the worst in this regard.
I've invested serious time looking for a maintainable speed pedelec. There are some limited loopholes and grey zones. Some manufacturers used to produce speed pedelecs according to the less strict 2002/24 legislation, with less DRM. Ignore some of the most draconic legal overreach, one incurs only very minor risk.
The main issue is legal really. For FSM's sake, even the Swiss speed pedelec regulation is so much more relaxed than the EU one! Switzerland is hardly known for being a laissez-fair jungle capitalist deregulator, right?
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.
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
kris de decker
Thank you for that information. Speed pedelecs were in none of the studies I cited but what you write is concerning.
Depends how you look at it. For me, this article is not really about bicycles, it is about capitalism managing to destroy everything, even a sustainable icon like the bicycle. That is the important matter to attend instead of focusing on technological solutions for whatever you find more relevant than a bicycle.
The studies that I rely on do not all have the same system boundaries. The widest boundaries are taken by the Bortoli paper 8, which also includes the infrastructure (like cycle paths, parking, bike sharing stations). The electricity mix in the studies is almost always the electricity mix in a certain country, and almost never on an "ideal" 100% renewable energy supply. These national data usually do not take into account the energy it takes to build the infrastructure. The emissions required to mine the materials for the bikes and the batteries are accounted for in all studies.
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 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.
Thank you for the detailed article. My 2 cents:
1) 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.
2) 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.
@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.
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.
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:
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.
Step one: Use local labor so you don't have to plow a big dirty boat across an ocean everytime.
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.
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!
Thanks for all this great information, and your personal comments about biking brought a smile to my face, several times. Carol
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.
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.
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.
kris de decker
"More people on bikes is what we want. Your thesis is unlikely to assist in this."
Why? Does my article discourage cycling? I make clear that even the most unsustainable bike beats the most sustainable car.
I find your reasoning problematic. Because what you say is that it is forbidden to be critical of anything that is meant to replace the default carbon-intensive technology. I would need to delete at least half of the articles on my website, because if I would follow your advice I can't be critical of electric cars, wind turbines, or solar panels.
"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."
My Gazelle has aluminum wheels but my three other bikes all have steel wheels. I don't know if the Gazelle originally had aluminum wheels (could be) because the wheels are not the originals.
"There are also a lot of half-truths in your assertions about the current state of the bicycle industry and the availability of parts."
I am not a bike mechanic. Like any other topic I write about, I do research and rely on references written by experts to write my articles. You can question those references (they can all be found below the article) but I have not invented anything or built any conclusions based on guesses.
kris de decker
Biking has obvious health benefits and could lead to significant reductions in health care energy use. But that doesn't change the conclusions of this article. The equation is not between bikes and cars, but between different types of bicycles. Furthermore, you don't need to take into account effects on healthcare to demonstrate that the bike is more sustainable than the car. It is already by simply comparing energy use during the manufacturing and use phase.
"If you want a cheap, versatile and reliable machine, look for early 90s mountain bikes"
Agreed, and I was riding one of those until 2013. It still gets use when a friend needs a bike. But it took me 1.5 hours to get to the city, with the road bike it's 1 hour...
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.
kris de decker
"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?
Have a look at Roetz bikes in Amsterdam. They currently do rebuilt bikes from old frames. They're also launching the Roetz Life  ebike. Stainless steel instead of aluminium. Their stated goal is to build a bicycle for life. Not affiliated with them in any way.  https://www.roetz.life/discover/
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.
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!