1 banana = 3.4 miles

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Mick F
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Re: 1 banana = 3.4 miles

Post by Mick F »

Ayesha wrote:The mpg number on a new car's sticker is gained from a specific laboratory emissions test. The test is strictly controlled so every manufacturer performs the same test. Then mpgs can be directly compared.
Yes, I understand that. It's the best system, doesn't make it right though.

Pick two cars with identical mpg figures. One could have a bigger engine or one could weigh more than the other but constant speed mpg lab tests are the same. In the real world with hills and traffic and loads of short distances could make the two cars very very different indeed. Overall economy can vary from car to car even though they may have the same publicly advertised figures.

I don't know how it could be done, but some figure for fuel consumption per mile per hour per load weight per acceleration per cold starting could be better. There are too many variables to make the publicised mpg figures any use at all.

There was something on the radio a few weeks ago about the way that the manufacturers test their cars, and one lady went into an argument with her car's manufacturer because she wasn't getting the mpg figure they specified. She lost the case because they said it was "her driving style". She disagreed, but the big boys won anyway.

It didn't make them right though.
Mick F. Cornwall
snibgo
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Re: 1 banana = 3.4 miles

Post by snibgo »

Ayesha wrote:If your entire mass is 400 N, ...

Newtons measure force (or weight), not mass. 400N would be a very small person.

I'm a skinny bloke at 67 kg. Plus bike etc 17 kg makes 84 kg, or about 840 N.
DaveGos
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Re: 1 banana = 3.4 miles

Post by DaveGos »

kinel , I thought this thread was supposed to be a bit of fun, its got a touch an**** retentive

I have done 7000 miles this year , can someone please calculate how many bacon sandwiches I can consume for that . PS I do not have butter on them :D or sauce. I am ready to put my order in now :D
Edwards
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Re: 1 banana = 3.4 miles

Post by Edwards »

DaveGos wrote:I have done 7000 miles this year , can someone please calculate how many bacon sandwiches I can consume for that . PS I do not have butter on them or sauce. I am ready to put my order in now


Forget about MPG more important to most cyclists want to know how much cake per mile CPM? :lol:
Keith Edwards
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snibgo
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Re: 1 banana = 3.4 miles

Post by snibgo »

DaveGos wrote:... its got a touch an**** retentive

Not me. If I was, I would have also pointed out that 400N times 80m was 32kJ, not 160kJ.
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Re: 1 banana = 3.4 miles

Post by dougie »

Ayesha wrote:
Gearoidmuar wrote:
Ayesha wrote:PS Dougie and I are svelte race whippets with hardly any width.

That's made my day!
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Re: 1 banana = 3.4 miles

Post by dougie »

Edwards wrote:
dougie wrote:Just for a bit of fun having clocked up 2000 miles since January (I wish it was more but that's another story....) I thought I would play with some numbers...


I bet you wish you had not started this bit now. :?

dougie wrote:The cost of de-stressing, good worthwhile exercise, quite reflections, seeing so much more in the countryside than driving my car = priceless!


I do not believe you could be challenged on this by any sane person. :wink: :roll:

Edwards - spot on - and a voice of reason - I had no idea the thread would grow like that. Hey isn't that the nice thing about this forum?!
Edwards
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Re: 1 banana = 3.4 miles

Post by Edwards »

dougie wrote:and a voice of reason -


I just told MrsE this and her reply would break forum rules if repeated.

I am still waiting to find out how much cake I can eat, my favorite is Victoria Sponge.
Keith Edwards
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dougie
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Re: 1 banana = 3.4 miles

Post by dougie »

Edwards wrote:
dougie wrote:and a voice of reason -


I just told MrsE this and her reply would break forum rules if repeated.

I am still waiting to find out how much cake I can eat, my favorite is Victoria Sponge.

Cakes per mile, good question....
hungrydave
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1 banana = 3.4 miles

Post by hungrydave »

Mick F wrote:MPG is a stupid method of calculating fuel consumption. It takes no account whatsoever of driving style or terrain. I suppose it's the best method we have, but it doesn't mean it's a good system.

This is the same with cycling. Riding a bike takes TIME not miles. Miles can be easy or difficult, fast or slow, boring or entertaining or any other variable. Hilly terrain takes longer to ride than flatlands for the same distance.

TIME is the thing that matters. How long will it take to cycle to work? How long have I got until tea time when I can ride home again? What time will I get home?

Cals per hour is a better figure and more worthwhile than cals per mile. I'm not an athlete, far from it and I tend to put the same effort into each and every pedal stroke - using gears to vary speed as much as I can. I come to a hill and change down so the power in my legs remains the same, this then makes me slower, making the distance per time smaller. Therefore it's time that matters, not distance.


This isn't correct - energy required is a product of moving a mass over a given distance. Eg. Box weigh's X, it takes Y energy to move it Z distance. In a perfect system, the energy required will always be the same irrespective of the speed of work. So moving it quicker requires a shorter higher intensity burst of energy.

Clearly systems aren't perfect and other factors come into play with cycling - resistance, efficiency, energy loss through heat etc - but the primary relationship is always between mass and distance.

The energy per hour is a product of this, which explains why it goes up when you are going faster.

Ran Fiennes and Mike Stroud (his fellow adventure, doctor and performance physiology researcher) suggest as a loose rule that it takes 100 kCal to cover 1 mile in foot, whether running or walking. Eg. It takes 1000 kCal to walk at 2.5mph for four hours or to run for 1.25 hrs at 8mph. kCal per hour will be greater in the latter example but the constants needed to calculate it are mass and distance.
hungrydave
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1 banana = 3.4 miles

Post by hungrydave »

DaveGos wrote:kinel , I thought this thread was supposed to be a bit of fun, its got a touch an**** retentive

I have done 7000 miles this year , can someone please calculate how many bacon sandwiches I can consume for that . PS I do not have butter on them :D or sauce. I am ready to put my order in now :D



About 933.3, assuming you don't have butter or ketchup.
snibgo
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Re: 1 banana = 3.4 miles

Post by snibgo »

hungrydave wrote:... a loose rule that it takes 100 kCal to cover 1 mile in foot, whether running or walking.

Yes. That assumes foot-power doesn't reach speeds where air resistance becomes significant. Cycling does.

When cycling, the energy demand per unit distance from rolling resistance (in kJ/km or whatever units you want) are pretty much constant. But the demand from air resistance increases with the square of the speed.
hungrydave
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1 banana = 3.4 miles

Post by hungrydave »

Yep, I agree with you. That's what I meant about other factors and efficiency.

The starting point is still mass and distance but you would need to overlay other elements like wind resistance... Which would exceed my GCSE understanding of physics!
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Mick F
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Re: 1 banana = 3.4 miles

Post by Mick F »

I totally agree with you Dave, but we're not discussing physics - well I'm not! :wink:

I'm saying that any activity takes TIME, especially cycling. The vast amount of any journey by bike is uphill. The flat bits and the down bits are over in a flash and can be almost ignored. The energy expended is on the uphills, and they take TIME.

Total distance is immaterial.
Mick F. Cornwall
Edwards
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Re: 1 banana = 3.4 miles

Post by Edwards »

hungrydave wrote:About 933.3, assuming you don't have butter or ketchup.


So how many Bacon Butties per mile or MPBB?

If dem dat is gud wif maffs work deese fings out den de rest ill ave bin lessoned in dis stuff
Keith Edwards
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