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There are so many questions that come to mind for the whole cycling and thermodynamics conundrum. No idea what the answers are - hopefully someone will....
The cycling me probably had a lower bmi than the non-cycling me. Does the lower bmi me consume less energy for the 23 hours a day I'm not cycling to work?
How does metabolic rate differ fit vs unfit?
Does a higher resting heart rate mean you are consuming more energy just sat around?
A good chunk of energy is used just existing and heating / cooling to keep the core around 36 deg. How much does body mass change that?
Poop. How much energy is excreted? How does that change with fitness? Metabolic rate? Amount you eat? If you over-eat, does the ratio of energy stored:excreted change or is it constant?
If I get fitter, and less fat, what does that then do to my carbon emissions?
I might live longer, increasing them. I might use less health care, decreasing them (health care is quite a big emitter). I might stay active for a greater proportion of my life, so driving fewer car miles. I might become sexier and so have more children, sending my emissions off the scale, or the opposite because I'm that guy who spends all his spare time stroking bikes in his garage...
Assuming a lifetime travel of 19,200km
I would have thought that only a tiny percentage of bicycles every make it to 19,200km...
I have a nice bike (not particularly fancy) which gets driven many miles to ride every time, and a borderline scrap bike for the occasional commute and evening fresh-ish air ride from my door. Reality of living in an urban conurbation, I can't adapt my likings from MTB to cycle lanes/tracks. I'd love to live somewhere where I could ride stuff I like from the door, but like most people where I live is very curtailed by job availability and house affordability.
This summer by my rough calculations, I drove my bike 5 times longer distance than I rode it.
What's the calcs on a motorbike? They're pretty much a luxury in most cases.
Spending time in hospital has a HUGE carbon footprint.
How many days in hospital are saved by excercising by cycling and not sitting in a car.
Coulds also apply to ebikes keeping people moving who could not otherwise get out.
Very hard to factor in this aspect to the calculation.
munrobiker
Free Member
It’s sad that this has already dropped off the front page of the forum. And it’s not appeared in the news feeds here or on Pinkbike. It’s like nobody cares, which is probably true and a terrifying indication of what’s going to happen to the world in the next fifty years.Posted 9 hours ago
I fundamentally disagree with making this problem about the individual. if it comes down to individual choice it'll never happen and that is essentially absolving governments of their responsibility.
The scale of the problem is too big to be left to a choice, it needs decisive governmental action, on a world wide scale.
individuals aren't going to solve it. It's systemic change that's required.
I agree, although I agreed with Luke as well tbh!. This needs more than relying on people to do the right thing, and the odd feisty speech from Doris.
I agree the vast bulk of the impacts have to come from governments and we employ a government to manage externalities like environmental impact.
However, individuals vote for governments. Individuals making changes scale up to lots of individuals, to demand for products (and we see here a company responding to presumably its customers and employees demonstrating they care enough) and to changing opinion in others, which then changes some votes, and eventually changes governments. That can be either by kicking one out for a different one, or by the incumbent recognising some voter pressure. Debatable, but I think we are at least starting to see a bit of that.
For me, buying a bicycle and using it til it's pretty much worn out is generally going to be a pretty decent thing for a person in the developed world to do with themselves by comparison with what a lot of their peers are doing.
Not sure how to define worn out, but if it's gone through a few sets of bearings/cogs it's probably done more than most. Frankly, I suspect 1,900 is as likely an average lifetime km-age as 19,000. I reckon I get decent lifetime out of my bikes but my mountain bikes haven't done that, and only the frames remain. I've bought so many replacement bits along the way that really I need to add in the CO2 associated with manufacturing those too, if I'm then going to divide total emissions by 19,000km.
Adding food emissions is a bit academic isn't it? If I was an athlete I'd eat more to ride more, but as a moderately fit 45 year old I think the impact on my food consumption is minimal. Plus it's not the bike's fault I choose to eat beef over tofu.
Even wonder whether sometimes cycling might reduce my food carbon. Do I eat more veg and pulses as part of an overall move to better fitness? Personally, I'll have a grainy salad over a burger in the middle of a big day on the bike.
+1
In fact that calculator may be under estimating compared to this table but it’s pretty conclusive that any exercise will necessitate increased calorie burn.
So it absolutely does make a difference
Only a small difference to your calorie burn. Unless you actually eat more, it won't make any difference to your CO2 production. If you eat the same amount of food but completely stop exercising, you will gain weight. Being fatter will cause your body to burn more calories at rest, so it will find a new balance between calorie input and calorie burn. If you exercise more without increasing your food intake, you will lose weight and your body will react as if there is a famine and burn fewer calories.
A lot of your food isn't digested and exhaled as CO2, it pops out your bum every day as shit. That decomposes and will ultimately turn into CO2, so the amount of food you eat is what determines your CO2 production, not the amount of exercise. If you commute to work on a bike and eat the same amount of food as when you drive, your CO2 production will be the same overall. If you switch from running to cycling and eat the same amount, your CO2 production will stay the same. If you increase your exercise and eat more, your CO2 production will increase, but you really have to do a lot of exercise to make a huge difference to your calorie burn.
People like bikes and boots and luket may well not keep their bikes for long and drive to ride a lot - but then I see people riding 70s bikes still that have not been upgraded at all and they ride them every day to work! That bike will have done many tens of thousands of KM
Both are outliers
ONe of my bikes is 60+ years old and I ride it perhaps 100okm a year
another of my bikes the frame is 30 years old and most of the parts on it 20 yrs old and I am its 3rd owner
Then there is the huge second hand market..............
They are not saying everv bike has that lifespan and mileage but that that is the average. Most folk on here are not representative of the average bike user
Agreed. But while there are those old high milers at one end of the scale there are many bikes that sit in garages hardly used for 10+ years.
Plus I just think the average is much lower for mountain biking. My last mountain bike did me for 12 years, and while 19,000km is in the order of magnitude of what it probably did (I'd still estimate lower though), it was the oldest bike on pretty much any group ride by the end, and was a right old triggers broom. On the road, though, fair enough. I too have a 80odd year old bike, which I think is on mostly original parts, and I adore it. It was my gran's. But I only ride it to the very nearby pub for fear of my personal safety on rod brakes, and because even as a regular singlespeeder it has me in awe of the legs she must've had in the war with that ratio.
Anyway, I still think good on trek for doing and publishing their analysis. And as with any analysis, there is plenty of room for debate about it.
The scale of the problem is too big to be left to a choice, it needs decisive governmental action, on a world wide scale.
Oh god, yes. But until a government falls on that sword by telling businesses they can't pollute and people that they can't do what they want all the time it's up to the individual to do what they can.
In cities there are a lot of old bikes doing the rounds that I suspect reach that 19,000km figure. My wife's commuter is twelve years old, fine and she expects to keep it til she's dead or it gets stolen. Her modest 3.5 mile commute each way adds up over the years.
Cycling as a sport is obviously going to be part of the problem not the solution. Tiny upgrades to technology that really only professionals will notice, annual product cycles and ever changing standards (all of which Trek are particularly bad at) are not great. They convince average punters they're getting left behind, missing out or have cause to blame their equipment. When in reality, most riders could keep a bike going for a decade and enjoy their ride just as much. All bike rides are good.
Plus I just think the average is much lower for mountain biking
Which is a small subset of cycling. thus irrelevant to the averages. also your experience does not stand for all
I have a MTB that is only 4 years old and has done perhaps 3000 KM. I have another that is 30 years old - 20 in my possession and has done perhaps 25000 km with me and who knows how many with a previous person and has not been upgraded since I got it. My mtb tandem is 25 years old 17 years with me and has done 30 000+ km and again heavily upgraded in the first few years and not touched since then ( bar fitting a rohloff) all upgrades were second hand parts as well bar the rohloff
Now I am almost certainly an outlier but my bikes have done far more than the average figure - and thats not including my road bike which will have done more by a huge amount.