A great read+great magazine.
TL;DR: Old bikes last way longer than new bikes. From a production standpoint, steel bikes have a smaller carbon footprint than aluminum or carbon frame bikes. Conventional bikes use fewer consumables over their usable life than electric bikes. Among electric bikes, cargo bikes use the most resources to run and maintain.
I can’t help but feel like this is thinking way too far ahead. It feels to me that society has to get people into riding bicycles as an option before even thinking about refining the processes around building bicycles. A big factor of lifecycle (heh) assessment is the amount of usage you get out of a given produced object before it becomes necessary to replace. Making the option to ride the bike easier, more accessible, more inviting is how you make bicycles more sustainable.
re: carbon fiber cargo bike emissions
Clearly there needs to be more studies because this feels like very narrow view of cargo bikes especially when the market for consumer cargo bikes is largely occupied by Urban Arrow (aluminum), Riese & Muller (aluminum), Larry vs Harry (Aluminum), and many more that construct cargo bikes out of aluminum or steel. Just looking at some commercial models of cargo bike it seems like for the most part those are made from aluminum as well. I believe that Urban Arrow offers models for businesses.
edit:formatting
I’m not really convinced that lifecycle carbon emissions are the right measurement for most people in the US (and maybe other developed countries, idk). A car is already a given for most people and is a possible option for every trip you take so the best bike is the bike that replaces the most car trips.
A steel frame bike might release less lifetime ghg than an aluminum frame cargo ebike but it doesn’t take that long for the ebike to catch up if the limitations of the steel frame means choosing the car more often.
napkin math:
(ebike_mfg_ghg - steel_mfg_ghg)/(car_ghg_per_mi - ebike_ghg_per_mi) https://www.wolframalpha.com/input?i=(320kg-35kg)%2F(400g%2Fmi-(41kg%2F15000km))
An aluminum ebike only has to replace 720 miles of car trips that the steel frame wouldn’t to cancel out it’s additional manufacturing emissions. In my experience that really not a crazy number when ebikes:
- expand your radius of effective trips
- reduce the time it takes to make trips
- expands the number of destinations (don’t want to be too sweaty or tired)
- can safely carry much more (grocery or shopping trips)
In the long term with changes to infrastructure or density (or if you already live in NYC or similar) then I think lifetime emissions of bikes starts to become a more effective measure to watch.
i found the AI generated tldr that you originally posted to be a bit confusing, but the article itself was very interesting. Here is my summary of the major points:
- from a production standpoint, steel bikes have a smaller carbon footprint than aluminum or carbon frame bikes.
- conventional bikes use fewer consumables over their usable life than electric bikes.
- among electric bikes, cargo bikes use the most resources to run and maintain.
to simplify this from a long-time bicycle commuters perspective: steel is real 😁
So the least efficient bicycle is about half that of the average car. I’ll take that. Since the lifetime miles traveled on any bike is going to be at least an order of magnitude less than the average car miles traveled, infrastructure and lifestyle changes to replace car reliance with bike reliance are hugely beneficial from the perspective of reducing carbon emissions.
Feels like it’s less cut and dry than this article suggests…
It’s weird to me to assume the lifespan of a steel frame vs aluminum when only looking at a perfectly maintained bike. A poorly maintained steel frame rusts out way faster than a poorly maintained aluminum one (does the oxide ever get past the very outer layer?), and I’m not sure anyone bothers recycling the steel bike frame but they do recycle the aluminum one. Also, we’re just looking at manufacturing, but wouldn’t a lighter aluminum bike require fewer calories to move and therefore cause less carbon emissions from the rider over the lifespan as well? Never mind they mention transportation emissions of old vs new but what about new vs new? Would a local aluminum frame be better than a Chinese steel one, especially if considering the other points I’ve raised above?
I guess the point I’m trying to make is maybe now isn’t the time to really be looking at this. Maybe get more people biking, any bike, and if it becomes a major enough form of transportation then we can worry about transitioning people from better to best.
I cannot imagine that marginal calorie burn from the 1-2 lbs difference in frame material is going to outweigh the impact of manufacturing costs and longevity of steel vs aluminum, though I do agree that these should be likey addressed after bikes have the infra and adoption sorted out. E-bikes still represent the best solution towards replacing car trips for the average person imo
From a purely anecdotal standpoint, I do have a thirty year old steel bike that I still use to cruise around, but I do have a much newer bike for exercise and long distance. I’ve had my steel bike tuned up a couple of times over the years and all the bike shop people say it’ll basically last forever since there’s no plastic on it, which is great.
But I do agree with another poster here in saying we have to get people to know that cycles even exist first. And beyond just regular people city planners and those with the means for change. I’d love to cycle and get groceries where I live, for example, but the infrastructure is poor and dangerous, so I just drive.
