I assume those calculations are based on the USA being flat and there being no wind. Struggling up and over the Rockies in a Force 9 might add a bit of fuel consumption, I guess.
Going back down after the wind has turned will make up for it. 
Yes, but…
Make sure your bike fits you and is adjusted properly, and that your joints track properly as you ride. Watch for uneven or side-to-side wear patterns on your shoes or cleats. Double-check everything and consider seeing a sports doctor if you start feeling joint pain or roughness, especially in the knee.
Not that I’m a doctor or anything, but I’ve had chondromalacia patella. I didn’t like it.
Somebody please correct me if I’m wrong but I thought the “calories” reported in nutritional info are actually kilocalories. That means a bushel takes 55,164 BTU or 13910 Kcalories, and yields 21773 Kcalories.
That said, I think your conclusion of 1000 Kcalories = 1/3 of a mile is still correct.
I think you are right, but the “calories” in the above cites are consistent, so the calculations are correct…
Regardless of all the calculations, it should be pretty obvious that cycling to work on a 30lb bike is going to be a lot more energy efficient than moving a half-ton chunk of metal all that way.
This topic has been up before. And I still fail to see why this is “obvious”. What if we assume that you eat a steak to get the calories back. Then there will be energy use to grow the cow food, transport it, house the cows, process the cow meat, transport it, etc. In the case of the oil, there is also energy used to transport it, and an implicit use in finding new sites etc. But Im quite sure the first number is much higher. Whether the difference between these two numbers is large enough to offset the primary difference between cycling and driving is a different matter, but I don’t see how it is obvious.
The “obvious” part comes from the fact that a bike weights and order of magnitude* less that a car. So unless producing a steak is an order of magnitude less efficient than producing the equivalent energy content of oil, simple ‘F = Ma’ means that end result will be a win for cycling, irregardless of whatever other considerations come into play.
-
- EDIT: Actual two orders of magnitude, my bike weight tens of pounds, my car thousands.
Again there are so many factors against the car that it is pretty obvious. Some of the more glaring ones:
A - As mentioned above, the difference in weight between a car and a bike.
B - As I pointed out earlier in the thread the basic environmental math is different. For cycling the “carbon cost” is JUST the cost of producing food (tractors, trucks, combine havesters, etc), NOT the carbon produced by my respiration. For oil both things are “Carbon cost” (i.e. a net long term GAIN of carbon in the atmosphere) the cost of producing the oil, AND the cardon produced by the engine.
C - The fact its only the EXTRA food I consume that is a “carbon cost”. As times goes on this will get LESS as I get fitter (as opposed for a car which of course gets less efficient as time goes on due to wear and tear). And in some cases (e.g. if I’m going to the gym when I drive, but not when I cycle) may be ZERO.
Yes, I agree this is obvious. My point is about the efficiency of making the steak.
B. That’s true. But to me, that list for food production carbon cost sounds like it’s a lot higher than the oil production cost. As to whether it’s still higher when you add the carbon produced by the engine, I don’t know.
C1. If not combined with weight loss, will the energy needed to perform some work decrease when you increase fitness, to a capital letter degree? Actually, it doesn’t really matter whether the value decreases or not, but just what the overall average value is.
C2.Also you might like cycling, and get a desire to do even more sports, which will further increase your energy intake. I know this is silly. I’m just trying to point out that this line of thinking doesn’t work.
Its not inconceivable it could be less that the oil, if you’re talking about meat (as opposed to plants, which don’t have the intermediate animal raising to factor in), and simply take into account the raw number of Joules of energy, but by so many orders of magnitude as overcome all the other factors (each of which alone would make cycling far more “green” than driving) that beggars belief IMO.
How about a motor scooter.? Less green but sure easier to get to work.
Mr. Jp is conflating eating steak, and biking. Not a logical pairing, and certainly not a statistically verified fact to present.
The energy budget to be examined is, does the increase in metabolic fuel needed to move a human being and a bike distance x, minus the metabolic fuel needed to maintain the same human in a car, less than the carbon fuel needed to move the human, and the car that same distance, plus warm up, and traffic variable, and parking.
I don’t have the numbers available to do the final analysis, but it seems silly to even consider that the ton of metal is a negligible environmental factor. The silliest part is the implicit assumption that the human will increase his carbon intake as fuel in direct proportion to the work of riding the bike, and that the driver would never dream of eating a steak.
People don’t eat steak because it has more energy in it. Grain has more energy, that’s why we feed it cows, to get the steak. And we don’t make them ride bikes, either.
What unmitigated claptrap!
Tris
Hmm, I’m not sure you understand. The point is that if the human uses more energy by cycling, he will also increase his energy uptake. That energy has to come from somewhere. And when preparing that energy for human consumption, a lot of oil will be used.
If the driver also eats a steak, the guy on the bike might eat a slightly larger one.
I’m not sure what your point is here. The steak was just an example, to illustrate how much goes into producing food. If we are going to do the actual calculations, of course the cyclist would eat an extra part that is equivalent in composition to his normal overall diet.
Unfortunately for you, the fact is that I do understand.
You ignore the cost of creating, maintaining, not to mention moving moving the 2000 lb automobile in one case, to the forty pound bike in the other. If you want a real comparison, you don’t look for ways of making one side account for only the trip, and the other for maintenance of the equipment. You also ignore the maintenance of the human equipment of the driver except your assumption without evidence that his intake will be more. It’s made up claptrap. And not even particularly well done made up claptrap.
Tris
I assume that the bike and car are already there, and then you have the choice.
This is not without evidence, it is in fact very basic biology. If you exert yourself more, you use more energy, and thus you increase your energy uptake.
I feel a little silly for giving a cite for this, but here you go:
http://www.urbanext.uiuc.edu/hsnut/hsath1a.html
It’s already been covered!
Sure, you could pick the most energy-intensive food to get your extra calories from (Chocolate, Kobe beef, Fois gras?), but unless those sources are 10x less efficient than corn (which is probably not the most efficient source to begin with (Soybean or rice might be better), than biking is still a win.
An assumption that ignores the energy cost of owning both the 2000 lb car, and the 28 lb bike.
Yet your cite is not a basic biology source.
And if we were discussing two machines, the comparison would be mathematically valid, and even somewhat applicable.
And there I went. It isn’t even a basic nutrition source. A human is not a mechanically isolated system that responds reliably to a food intake work output analysis. People eat for lots of reasons, energy needs being only the most basic. In a nation where choices between cars and bicycles are daily alternatives, that simple demand/response argument is simply absurd.
The actual analysis of the problem is either every complex system, in each of the two cases, or simplification of both cases in the same way.
Work equals the total weight 2200 lbs vs 228 lb for a standard distance traveled, or it is an in depth analysis of the entire energy budget. Choosing to complicate one side of the argument is not reasonable. It is transparently biased, by deliberate choice. It is made up claptrap.
No wonder you feel silly. Perhaps shame would be more appropriate.
Tris
Yes, you are right. And that were some excellent calculations you did there!
I actually think that any sort of meat is easily more than 10x less efficient than corn. In fact, a cow or pig will eat rather more then than 10x the weight of it’s meat in corn during it’s life. And that’s not even considering the cost to house the animals, or process the meat etc.
Of course, the cyclist will not eat pure meat to regain the energy. But he will eat maybe 30% meat, and if the cost of that is, say, 200 BTU/calorie, then the matter doesn’t look certain anymore.
Some sources quote 5lbs corn/lb of meat.
This says a meat-fueled cyclist is equal to 31MPG, so still better than most SUVs.
However, assuming worst-case conditions isn’t really fair. What about free-range cattle, or eating a normal diet?
Ok, I am convinced. Cycling is much more green.