Orbea Onix, the best Spanish bike made in Taiwan ever.

The major change in material in the decades since I stopped racing has been the rise of carbon fibre. Unusual at the beginning of the century it is now the default choice for the serious cyclist.

Carbon fibre at heart is sheets of light, woven, material that you make into shapes and set with resin. And carbon sheet is really light. You know nori, that seaweed that wraps around sushi? It’s that light and looks similar in a raw form but is floppy like silk. If you think of a couple of hundred of sheets of that, from stamp size up to several feet long, that’s what a carbon bike is made of.

You alter the feel of the bike by changing the amount of carbon and the direction of the ‘weft’ of the sheet. Bike design in carbon fibre has a lot in more common with the drapery of haute couture and the design of sails than it does with metallurgy and the welding torch.

Many carbon pieces for one frame.

Which just reminds me of mum's old Burda sewing pattern magazines...

Carbon frames are lighter, so much lighter, than a steel frame. I remember picking up a carbon frame at a bike shop and being astonished at the weight - it seemed a bit like voodoo. And even at half the weight of a steel frame they are stiffer. There doesn’t seem to be a down side.

In 2010 I yet to ride a carbon bike. I had often looked over one in a bike shop and read plenty of reviews but still didn’t have any experience of it and no idea what the fuss was about. So when a reasonably priced second-hand carbon race frame came up in one of those forums sometime around 2011 I bought it. An Orbea Onix; a middle of the range nominally Spanish frame that was no doubt made in the best place in the world to build a good carbon frame - Taiwan. And it was white, always the wrong colour for a bike.

It took me a long time to pull the parts together for this one, a good four months, so by the time I got on it I was dying to know; how fast was it?

And by extension, how fast am I? I hadn’t thought about objective speed for decades. I always liked riding fast but only for the way it made me feel. Objective performance (e.g. racing) I had left behind. I guess this bike was my very moderate indeed midlife crisis high point.

The short answer was that the bike was very fast. With some relatively deep and light aluminum wheels on it it reached the magic 20mph markedly easier than the Salsa. I found I could reel off shorter rides a good 1-2mph faster overall with about the same effort. In racing terms that’s a country mile.

I took it out one day early on, around a ten mile loop. I used to be able to do 10 miles in around 24 minutes as a fifteen year old on a soggy old steel bike. So now?

Well I got around in under 30 minutes and I had to kill myself to do it. To put that in context the record for 10 miles on a penny farthing from the 1870s was 34 minutes, and there are plenty of riders my age who could knock out 10 miles in around 22 minutes.

And it hurt, properly hurt - in that wonderful cleansing way that only exercise can. I loved the speed. I even contemplated whether I should train properly again and maybe do a race or, less humiliatingly, a time trial. And then I got real and got on with being a parent and fulltime worker and got back to riding Audax and mostly rode the Salsa because it was comfortable and quick. I rode the Onix on a few commutes and day rides every now and then, maybe 12 times in the first year I had it. I even tried a couple of Audaxes on it - I did my first 300 on it and even a 600. But even a ‘comfortable’ race bike is not something you want to sit on for the 28 or so hours 600km takes.

Come Autumn I stripped it down and put it in the attic. No mudguard capability, so not a winter bike.

Next spring, feeling frisky, I wondered if I should start training properly (again). I went for a couple of quick rides on the Onix (again), but mainly used the Salsa (again) until Autumn when I put the Onix back in the attic (again).

I did that for four years running. Sometime in 2015 I realised what I was doing and, the next spring (with other rides on my mind, we’ll get to that) I left it in the attic where it has remained ever since. I suspect I rode it less than 50 times in the 4 years I bothered to put it together.

The reality is that I am about as likely to take up racing again as I am to sit in a hide with a camera covered in camo and take photos of birds.

So now what I have in the attic is a fine piece of the carbon bike builders art. Which is to say a bike-shaped piece of rubbish. Worse than that it’s a piece of rubbish that I can’t throw away - a bike-shaped piece of climate-change guilt.

Stretching utility value by adding too many accessories to it; not it's best look.

About ten years ago I faced up properly to the fact that we have fucked the earth beyond redemption. It is, of course, a depressing thing to fully comprehend. There are no ‘sustainable options’, we are blindly careening into a future of chaotic weather and human misery. It’s the kind of realisation that makes you want to go back to the complacent 80s and start again, or to make you start hoarding guns in a remote mountain destination. The very least you can so is make the change as slow as possible by bringing less pollutants into the world - pollutants in the shape of plastic bags and cars and large houses. And carbon-fibre bike frames.

But there are subtleties around thinking about climate change. One of those is that, taken at an individual level, deciding to recycle properly or eat less meat has zero effect on the global outcome of climate change. And yet all those zeros have stacked up to a mountain. Climate change is a huge concept but it’s made of an astronomically large number of very small acts. It’s hard to get your head around and because it’s not human scale we struggle to think about it in the right way - it’s both too big and too small.

But there is one thing you can rely on and that is you are not throwing anything ‘away’ anymore. There is no away left. We know that ‘away’ means into the stratosphere or into the ocean or into the ground and that a year or two of use of something is not balanced by sticking it in the ground for a few millennia to leech whatever pollutants were used to create it back into the earth.

So what I think I have in my attic is small piece of frozen climate damage. Intuitively this feels bad. I have stewardship of a 1.5kg of stuff that must be bad for the environment. Carbon sheet is basically oily stuff. Resin is glue. So you can’t burn it and when you hit it with a hammer it shatters into a mess of small razor-sharp blades. And then surely all that glue and fumes and pre-processing of stange pellets to make carbon is about as toxic as it gets right? In short when you know what climate change is then carbon fibre seems to be an insult to logic.

But then I realised I wasn’t being logical about it at all. I automatically thought of steel as a more ‘climate friendly’ material for a bike frame. But really, is this right?

So I spent many hours (ok, six) trying to pull together figures for the manufacturing costs in energy and emissions of the materials used to make bike frames. I even went past the first ten pages of google results. It is hard to find figures and they tend to use different measures, so what I ended up with is probably a bit crap. I invite my more engineering-minded readers (hi Roger!) to pick me up on some of this - references at bottom of the page. But here we go…

Material Energy - kwh per kg Emissions - kg CO2 per kg Water used - l per kg
Steel 700 1.8 ?
Aluminum 1600 2.2 1200
Titanium 3000+ 3-5 ?
Carbon 420 0.6 2300
Bamboo Sunlight 0 ?

Bamboo? Yep, for real

Counter intuitive moment one: Making a bike frame out of carbon is significantly more energy efficient and has one third of the emissions of steel. That did surprise me, carbon is way better than all the steel and alloy frames for that. And you can make 10 frames out of carbon for the climate cost of one titanium frame. Carbon frame manufacture uses an awful lot of water though and I guess the key question there is how polluted that water gets and what happens to it after manufacture? That I couldn’t find.

Further reading provides counter-intuitive moment two: A carbon frame will last longer than an steel frame. Steels, aluminum and titanium all flex a little and as such have a failure point. Steel’s failure point may be decades hence, but nevertheless the inert nature of carbon means it will last many times longer than that - theoretically you could ride a carbon bike for centuries rather than decades. Some proof of that.

So is there anything wrong with carbon as a frame material?

What carbon doesn’t have is resilience. It’s brittle. When you hit it hard it tends to shatter. Steel bends, which makes it a little safer in an accident - it will fold beneath you rather than snap in two.

Carbon shatters rather than deforms, not great in an accident.

The final factor that people like about steel is that it is easy to repair. It’s no bother for a skilled frame builder to change a damaged steel tube. It must be said the number of times I have had a bike repaired in 43 years of bike ownership is exactly one - I had the rear dropout on one of my old steel bikes welded back together. It also must be said that carbon is eminently repairable too, but probably not in the back blocks of South America. Such things apparently matter to the .001% of riders who do such things.

I was right about the recycling and cardon. Not a chance. Not that it’s impossible it’s just not a thing yet. Research reveals there are precisely two places in the whole of Europe who do carbon recycling and neither of them will take a bike frame off the street. This will change when the first generation of airplanes made with a lot of carbon in them come offline - 95% of the carbon in the world is used in the aerospace industry. A couple of the big carbon manufacturers offer return and recycle services - I suspect they just have arrangements with these two businesses. That’s not really good enough.

So this carbon frame in my attic will last forever in its current form. Unlike tyres left in the attic for a decade it will not rot. It won’t oxidise in the rain. You can’t re-weld it into a lampstand. However if I did put it in the ground next to a steel frame and wait to see what happens the steel frame would start leeching toxic chemicals into the earth a lot sooner than the carbon.

The same thing has happened in the sailing world - there are thousands of early fibre-glass yachts that have been left to rot - but they will not rot, they will just settle deeper and deeper into the mud, waiting to be found in perfect condition tens of thousands of years hence. Wooden boats have the good grace to rot. A steel frame will at least rust and, centuries hence, become an oxidised pile of flakes.

So what we end up with is something like this:

Frame material Energy cost Emission cost of manufacture Longevity Resilience
Steel Medium Medium Medium Good
Aluminium High High Low Poor
Titanium Very high Very high Medium Good
Carbon Low Low High Terrible
Bamboo Very low Nil Medium Good

My conclusions on frame material is this:

  • If you are really concerned about emissions and energy at point of manufacture don’t buy Aluminim or Titanium frames.
  • Steel is a reasonable balance between climate damage and resilience, at least for the clumsy.
  • If you buy a carbon bike don’t crash it
  • Whatever bike you buy keep using it as long as possible

And it’s the last of those points that really makes the difference. What ever you have, keep it until it breaks.

Chasing trains of thought and accountability like this leads you down many corridors. You start thinking about supply chains and manufacturing efficiency, material resilience, embedded costs, lifecycle costs. It all leads to misdirected absurdities like me worrying about recyclable takeaway coffee cups and carrying around a recycled bamboo cup while outside the cafe I am writing this in there is a new building going up containing many tons of poured and reinforced concrete.

Concrete makes anything bike-shaped look like a rose bush when it comes to emissions and poison and decomposition but we simply don’t see it. All buildings really should be made of wood or brick or even steel but still we pour billions of cubic metres of concrete a year; a gamble of profit versus time that developers are only to happy to take because they will be well dead by the time that building needs to come down.

And once you start thinking like this you realise you have to look at all of it, the big picture. You need to look at the coffee cup and the concrete building, the material and the format and the supply chain and your own misguided assumptions about all of it.

So let’s go there. What about bikes and cycling in general then? How green is tit all as a thing really? We know that cyclists like to think of themselves as green, but what’s the reality of that?

Lets start with energy use per kilometre.

In terms of energy use and base lining on a ten mile commute a car is obviously the worst offender. A bicycle as an object uses zero energy and has zero emissions at point of use - but we have to factor in the energy use of the rider. Cars have a single source of energy (petrol/diesel) but the 300-500 calories an hour a cyclist burns is created from multiple food sources. Energy from a meat-heavy diet is more ‘expensive’ than from a plant-based diet.

I looked in that cupboard called the internet and found this interesting table:

Mode of transport Energy (MJ/km) Climate impact (gCO2e/km)
Prius, double occupancy .85 75
Cycling, vegan diet .2 80
Cycling, avg US diet .2 130
Prius, single occupancy 1.7 150
Cycling Paleo diet .2 190
Avg US car, single occupancy 3.3 300


Counter intuitive moment three: Two vegans in a Prius is ‘better’ than two paleo cyclists riding along together.

But then again two cyclists on Paleo don’t often do this…

What happens when multiple Uber divers lease one car and run it 24/7

This study doesn’t factor in other things like the energy footprint of production and disposal or the long-term saving to the state purse that fitter people bring to the equation and it doesn’t include the climate impact of the diet of the two sedentary occupants in the car, so I can’t say it makes me feel too bad at the transport level. It also doesn’t factor in the environmental cost of those batteries in the Prius. But it does give you food for thought - there is no automatic get out of jail free card for cyclists.

Amusingly the Guardian did its own analysis, which makes the point rather well: Cycling emissions per km travelled factoring in food production and transport costs:

  • 65g CO2e: powered by bananas
  • 90g CO2e: powered by cereals with milk
  • 200g CO2e: powered by bacon
  • 260g CO2e: powered by cheeseburgers
  • 2800g CO2e: powered by air-freighted asparagus

More recent figures on emissions considering the source of energy used to propel the vechicle per km are:

  • Bicycle: 21 g CO2/passenger/km traveled
  • Electric-assist bicycle: 22 g CO2/passenger/km traveled
  • Passenger car: 271 g CO2/passenger/km traveled
  • Bus: 101 CO2/passenger/km traveled (if the bus is full)

Counter intuitive moment four: Even factoring in the environmental cost of a massive lithium-ion battery it’s cheaper in environmental terms to ride an ebike than a ‘real’ bike because the source cost of all the extra calories you eat to power a real bike will vastly outweigh the climate impact of that battery and the electricity used to charge it.

Further to that the cost of running an ebike is about 1p per mile. Given my 20 mile commute I would have a budget of 20p to buy the extra 500 calories that the commute would burn. A decent 500 calorie lunch costs me around £5-£8.

So if the emissions are the same and the cost per km is so much cheaper we should all be buzzing about on ebikes. But then I would feel pretty bad about having to throw away that battery every five years. Because, remember, there is no ‘away’ anymore.

Young, affluent, yet relatable couple enjoying a perfect Ebike lifestyle

We could play this game forever and pursue detail until we burst but what this all amounts to is that if I really cared about climate change I would sell the car and forgo the bike for an ebike, or tube. And change my already rather restricted gluten-free diet to avoid meat altogether.

I could change my diet and lose the car but I could not give up riding the bike. That would be too big a loss for me of emjoyment and health. And the evidence backs that up; a cyclist has a longer life with better immunity, mental health and is generally a ton healthier than the average sedentary person. As for the supposed damage of dirty air and riding in the city the health benefits substantially outweight the risks.

So perhaps the long term benefit of riding a bike is an macro economic good - I might be more efficient riding an ebike but if I am so much less likely to be a strain on the NHS with my high level of exercise then bikes should probably be free. Maybe a bike every ten years would be a good investment by the government. But of course many people look down on cycling - a class thing we will come back to - so that wouldn’t work. And requiring people to ride a bike for health benefits can look a lot like opportunism and blaming.

Yeah... except when it's one more bike AND a car...

Cycling = green is a lovely thought and some cyclists genuinely are more green than the general population, but many of us are anything but. Even looking at the simple ‘One less car’ mantra - it’s only true if you really do have one less car. Like many cyclists I use my car more because I ride a bike - to drive to events. We don’t drive a lot but I reckon a third of the mileage of our car is driving to the start of Audaxs.

As for the carbon footprint of your cycling the following matter much a whole heap more than what your bike is made of:

  • How long you keep your bike
  • How far you drive (or fly) to begin your rides
  • What your diet is
  • Whether you buy new or not (second hand is obviously better)
  • Whether or not your bike commute genuinely replaces a car

Based on all that I am not a very green cyclist. I drive to the start of rides and eat meat and my commute doesn’t replace a petrol or diesel journey as I can take the brutally efficient but deeply unpleasant London tube to work.

But the main lesson of all this thought for me is - make everything last longer. Buy less. Stay with a bike for ten or twenty years not two to five. Buy second hand where you can. Of course you can and should apply exactly the same logic to all commodity purchases from cars to laptops and phones. And then you should learn how to fix what you buy, but then that rules out all those lovely Apple products…

So having put my climate-guilt into perspective I now have a couple of clear choices on what to do with that carbon frame in the attic: Build it back into a bike and use the hell out of it. Give it someone who needs it. Wait until carbon recycling becomes a thing. The very last thing I should do is buy a new carbon bicycle while that one sits in the attic. That. is. the. very. last. thing. I. should. do.

And finally astute readers who know their bikes will have realised that I have skilfully avoided the one question that really drives the carbon versus steel versus aluminum versus titanium debate among cyclists. It is not the relative merits of frame materials as climate damage objects that make us want one thing over another, it is what they feel like to ride. And this is a topic we will address next.

Next chapter: Interlude - Steel up


A life-cycle climate study that Specialized did on their own bikes (carbon and aluminum only) in 2014

Climate impact of biking vs driving, Harvard 2016

ECF - Quantifying Co2 savings of cycling (2011)