Arts said:

in case anyone wants to try for a fast cash…

Dear Reader,
Nobody has all the answers to the world’s energy questions, so New Scientist has teamed up with Statoil to create a special section of The Last Word to search for solutions.

We’re posing one energy question a month and the best answers will be published on The Last Word on Energy page in the magazine, with the authors winning £100 (or US$160). Try our latest question:

Does it take more energy to cycle up a hill or push your bicycle up?

Submit your answers online at newscientist.com/topic/energy by 9 December.

Please do not reply to this email – answers will only be considered if submitted as explained on newscientist.com/topic/energy, where you can also read more about The Last Word on Energy.

Good luck!

The New Scientist team

but it might make for some interesting conversation right here too.. what say you forum, push or ride? ?

i say the same energy. you are moving the same mass the same distance.

ChrispenEvan said:

i say the same energy. you are moving the same mass the same distance.

For the vertical component, yes. But it depends on the gradient of the hill. All things considered, a bicycle should be more efficient for most hills except the steepest.

Practical experience shows it’s a lot easier to push up the hill..

ChrispenEvan said:

i say the same energy. you are moving the same mass the same distance.

Not sure it’s that easy.

There is gearing to consider in the equation. I think this one is a bit beyond me.

Dropbear said:

Practical experience shows it’s a lot easier to push up the hill..

And probably almost as quick.

Saw a whole pelaton of fundamentalist cyclists go through a red light this morning, they were like a mob of sheep with about the same combined iq.

Peak Warming Man said:

Dropbear said:

Practical experience shows it’s a lot easier to push up the hill..

And probably almost as quick.

Saw a whole pelaton of fundamentalist cyclists go through a red light this morning, they were like a mob of sheep with about the same combined iq.

Did you consider mowing them down with the Triton?

Peak Warming Man said:

Dropbear said:

Practical experience shows it’s a lot easier to push up the hill..

And probably almost as quick.

Saw a whole pelaton of fundamentalist cyclists go through a red light this morning, they were like a mob of sheep with about the same combined iq.

Peak Warming Man said:

Saw a whole pelaton of fundamentalist cyclists go through a red light this morning, they were like a mob of sheep with about the same combined iq.

I hope you rolled down your window and remonstrated with them.

Witty Rejoinder said:

Peak Warming Man said:

Saw a whole pelaton of fundamentalist cyclists go through a red light this morning, they were like a mob of sheep with about the same combined iq.

I hope you rolled down your window and remonstrated with them.

You don’t roll down windows anymore you old coot.

Less energy to walk, when walk is optimized for that, which tends to be (and too few of us would optimize the bike proposition), but the joy of the bike is the trip down the hills, like tailgating an ambulance, for example :)

Skeptic Pete said:

Witty Rejoinder said:

Peak Warming Man said:

Saw a whole pelaton of fundamentalist cyclists go through a red light this morning, they were like a mob of sheep with about the same combined iq.

I hope you rolled down your window and remonstrated with them.

You don’t roll down windows anymore you old coot.

Lol :)

Skeptic Pete said:

You don’t roll down windows anymore you old coot.

My word. That’s a paddlin’.

Witty Rejoinder said:

Skeptic Pete said:

You don’t roll down windows anymore you old coot.

My word. That’s a paddlin’.

Yeah we don’t use paddles anymore either.

ChrispenEvan said:

i say the same energy. you are moving the same mass the same distance.

It would depend on the efficiency though.

My guess would be that for a flat slope cycling would be more efficient, but at some slope pushing would be better.

The Rev Dodgson said:

ChrispenEvan said:

i say the same energy. you are moving the same mass the same distance.

It would depend on the efficiency though.

My guess would be that for a flat slope cycling would be more efficient, but at some slope pushing would be better.

I’m going to take a SWAG and suggest that in going down hill that cycling will be more efficient.

sibeen said:

The Rev Dodgson said:

ChrispenEvan said:

i say the same energy. you are moving the same mass the same distance.

It would depend on the efficiency though.

My guess would be that for a flat slope cycling would be more efficient, but at some slope pushing would be better.

I’m going to take a SWAG and suggest that in going down hill that cycling will be more efficient.

Engineers don’t take SWAGs, they use BOTE calculations.

Over some incline people tend to raise from the seat and stand on the pedals and lean forward, more resembling a walk, still the feet are locked into a rotating action of X radius, which couldn’t be more optimal than a fit, well-adapted walker.

Was thinking the other day, that since the advent of motorised transport and the pressures of time, that what were once considered moderate walking distances today are more seen as long distances.

Same energy but more work to ride up the hill.

and the question is about energy not work.

ChrispenEvan said:

and the question is about energy not work.

I thought I’d just throw it in anyway.

It might come down to conversion efficiency and what is conserved, maybe in tendons even.

anything that backs up my answer is welcome.

http://en.wikipedia.org/wiki/Tendon

“…Energy storing tendons can store and recover energy at high efficiency. For example, during a human stride, the Achilles tendon stretches as the ankle joint dorsiflexes. During the last portion of the stride, as the foot plantar-flexes (pointing the toes down), the stored elastic energy is released. Furthermore, because the tendon stretches, the muscle is able to function with less or even no change in length, allowing the muscle to generate greater force…”

Assuming that your bike has low enough gears, it would take less energy to ride. Simply because you are sitting down and not spending energy holding your body weight against gravity. Wheels are more efficient than legs. It requires no energy to sit still on a chair on wheels, but it takes energy to stand still.

Kingy said:

Assuming that your bike has low enough gears, it would take less energy to ride. Simply because you are sitting down and not spending energy holding your body weight against gravity. Wheels are more efficient than legs. It requires no energy to sit still on a chair on wheels, but it takes energy to stand still.

But a thing on wheels will roll down the hill if left unattended, it requires energy from the rider to keep pressure on the pedals to stop the thing rolling backwards.

ChrispenEvan said:

and the question is about energy not work.

Same thing.

Increase in potential energy is just one of the energy changes going on.

party_pants said:

Kingy said:

Assuming that your bike has low enough gears, it would take less energy to ride. Simply because you are sitting down and not spending energy holding your body weight against gravity. Wheels are more efficient than legs. It requires no energy to sit still on a chair on wheels, but it takes energy to stand still.

But a thing on wheels will roll down the hill if left unattended, it requires energy from the rider to keep pressure on the pedals to stop the thing rolling backwards.

Apply the handbrake.

Perhaps if the chain were replaced with something that has energy storing capacity like a tendon, a high Q factor, things may be better.

On the subject of another Q factor this below is probably related to the subject of the title.

http://en.wikipedia.org/wiki/Q_Factor_(Bicycles)

“…The Q Factor of a bicycle is the distance between the pedal attachment points on the crank arms, when measured parallel to the bottom bracket axle. It may also be referred to as the “tread” of the crankset. The term was coined by Grant Petersen during his time at Bridgestone Bicycles.

Q Factor is a function of both the bottom bracket width (axle length) and the crank arms. Bottom brackets axles vary in length from 102mm to 127mm. Mountain bike cranks are typically about 20mm wider than road cranks.

A larger Q Factor (wider tread) will mean less cornering clearance (while pedaling) for the same bottom bracket height and crank arm length. A smaller Q Factor (narrower tread) is desirable on faired recumbent bicycles because then the fairing can also be narrower, hence smaller and lighter. Sheldon Brown claims that a narrower tread is ergonomically superior because it more closely matches the nearly-inline track of human footsteps.

Though it seems intuitive that a narrower tread is superior, a walking person must put their foot more to the centerline of the body to balance. This is not the case when pedaling a bicycle, where the “steps” are so very close together and balance a non-issue.

Recent scientific research has emerged from The University of Birmingham in the United Kingdom that shows narrower Q Factors are more efficient, likely due to improved application of force during the pedal stroke “

Why do we ride bikes? Because it’s much more energy efficient than walking. This is why when people who normally walk everywhere take up riding, they gain weight :)

>Why do we ride bikes?

Because rolling along at much over the maximum speed of human running, say 25-44.72KM/H (typical fit adults for example) tends to cause damage, not to mention takes a special type of effort, but you know if you can conserve your momentum and free-wheel it along, and then those downhill slopes you know have benefits like water pumped up to a water tank on top a hill.

Me, I tend only to ride a bike for the sexual experience.

transition said:

>Why do we ride bikes?

Because rolling along at much over the maximum speed of human running, say 25-44.72KM/H (typical fit adults for example) tends to cause damage, not to mention takes a special type of effort, but you know if you can conserve your momentum and free-wheel it along, and then those downhill slopes you know have benefits like water pumped up to a water tank on top a hill.

Me, I tend only to ride a bike for the sexual experience.

Those of us without cars ride bikes because it’s a faster and more efficient form of transport than walking. But we use more energy walking and thus tend to gain weight when we switch to bicycles.

>Those of us without cars ride bikes because it’s a faster and more efficient form of transport than walking. But we use more energy walking and thus tend to gain weight when we switch to bicycles.

Well, I suppose the bike proposition could be more efficient if doing it more quickly is in that, but otherwise the jury is out.

No, the energy efficiency of different forms of transport have been studied and are well known. Riding a bicycle is much more efficient than walking (uses much less energy for the same distance travelled).

>No, the energy efficiency = efficiencies

>No, the energy efficiency of different forms of transport have been studied and are well known. Riding a bicycle is much more efficient than walking (uses much less energy for the same distance travelled).

Dunno, chuck in a big hill etc things may look different.

It depends, typical speed parameters for comparison would have to be used, travelling at slow meandering speeds on a bike takes a bit of work. Depends if slowing and stopping to smell the roses factored into that.

Well yes, you’d think there probably is a certain gradient above which walking is more efficient than trying to ride a normally geared bike.

Probably the effort required going from a comfortable walk (suited to the incline) to higher speeds is more non-linear perhaps on foot than a bike, with the bike (optimally geared) it may be more linear (over a greater speed range).

Bubblecar said:

Well yes, you’d think there probably is a certain gradient above which walking is more efficient than trying to ride a normally geared bike.

Someone said that before.

The Rev Dodgson said:

Bubblecar said:

Well yes, you’d think there probably is a certain gradient above which walking is more efficient than trying to ride a normally geared bike.

Someone said that before.

In an infinite universe, someone’s probably already said everything I’ll ever say.

Of course, a lot of times when people are walking or biking these days, efficiency is exactly the opposite of what they want. They are doing it for exercise rather than transport, so want to waste energy.

Bubblecar said:

The Rev Dodgson said:

Bubblecar said:

Well yes, you’d think there probably is a certain gradient above which walking is more efficient than trying to ride a normally geared bike.

Someone said that before.

In an infinite universe, someone’s probably already said everything I’ll ever say.

But in a finite universe, even one hugely bigger than the little bit we can see, it is most likely that any other planet even has creatures that speak English.

dv said:

Of course, a lot of times when people are walking or biking these days, efficiency is exactly the opposite of what they want. They are doing it for exercise rather than transport, so want to waste energy.

Yes, people decide to ride bikes instead of driving in order to lose weight. And some of those people then find it hard to understand why I’ve gained weight by cycling instead of walking.

The Rev Dodgson said:

Bubblecar said:

The Rev Dodgson said:

Someone said that before.

In an infinite universe, someone’s probably already said everything I’ll ever say.

But in a finite universe, even one hugely bigger than the little bit we can see, it is most likely that any other planet even has creatures that speak English.

un

Where “likely” = “unlikely”.

And some of those people then find it hard to understand why I’ve gained weight by cycling instead of walking.

—-

plus it makes it easier for you to buy food …

he was warned by several posters that the bike was going to cut down on time spent being active. increase energy efficieny of activity and increase access to cheap piss and fatty victuals.

+c

che was warned

>>But we use more energy walking and thus tend to gain weight when we switch to bicycles.<<

You gotta push harder, ride faster…..and find some hills! I’ve got back my bike legs and it’s getting too easy, so I’ll have to start riding faster very soon. My usual ride (around 7km) has some coasting involved. And no really hard hills. But I can now use the hardest of my 3 gears whereas when I started again after Winter (a couple of months ago), I found that a bit hard except when coasting…

he was warned not to go to Bolivia

Peak Warming Man said:

Saw a whole pelaton of fundamentalist cyclists go through a red light this morning, they were like a mob of sheep with about the same combined iq.

I see every car that approaches a Stop sign, but is not forced to stop by traffic, fail to stop – Which is exactly the same offence and carries the same fine as failing to stop at a red light. How come you don’t make any fuss about them?

this question is solely about going up a hill. the gradient isn’t mentioned but could be assumed to be one where you have to decide which would be easier, to push or ride, so one that has a fair gradient to make you question. so lets skip all the going on easy rides or downhill or on the flat.

The relative efficiencies will be strongly affected by gearing, slope, speed, and fitness of the walker / rider.

it is a physics question so we’ll assume a spherical rider and the only friction will be between the soles of his feet and ground. his hands and the bike and the bike tyres and the ground. and he’s in a vacuum.

;-)

ChrispenEvan said:

it is a physics question so we’ll assume a spherical rider and the only friction will be between the soles of his feet and ground. his hands and the bike and the bike tyres and the ground. and he’s in a vacuum.

;-)

So the main resistive force he needs to overcome is… The price of electricity?

At the same speed it is easier to walk than ride even on the flat, too much nergy is spent balancing at slow speeds on a bike.

Does it take more energy to cycle up a hill or push your bicycle up?
———————————————

Well of course the answer is push.

Next question…

Mr Ironic said:

Does it take more energy to cycle up a hill or push your bicycle up?
———————————————

Well of course the answer is push.

Next question…

Please show your working.

I passed a bloke on a bike climbing a big hill on the Hume. Dunno what gear ratio he was at but his legs were a blur and he was hardly moving.

On a tall hill just up the road from me, a consistent climb for 3km, good running athletes (not pushing bikes) take four times longer than good riding athletes (who are carrying the extra weight of a bike).

If one considers them capable of producing the same total power output, this would suggest the cyclists might be five times more efficient.

Hope that helps.

Skunkworks said:

I passed a bloke on a bike climbing a big hill on the Hume. Dunno what gear ratio he was at but his legs were a blur and he was hardly moving.

Peak power output in cycling is around 110rpm (at the crank).

Please show your working.
————————————————-

Well as normal the answer is in the question.

Bikes are not designed to be pushed…

They wobble and over correct to the point of failure.

All this extra telemetry is working against the pusher.

But when one takes into consideration the energy it takes to *make * the bicycle, then, well, um…

(The energy to make the person is similar in both cases.)

We had that question on SSSF in the olden days. FIIK what we decided though.

All good scientific theory show symmetry. So if it take a shedload less energy to ride a bike downhill, rather than walk it, then it stands to reason that it must take a shedload more energy to ride it uphill.

All good scientific theory show symmetry. So if it take a shedload less energy to ride a bike downhill, rather than walk it, then it stands to reason that it must take a shedload more energy to ride it uphill.
————————————————————-

Ummm, arhhh, yes but,

So it requires no energy to drop a rock off a roof but a nearly infinite amount to get it up there…

Anyhoot it is the slowing of the descent where the energy is used.

bump.

http://www.newscientist.com/topic/lastword/pedal-or-push/

Pedal or push?
20 November 2013

Magazine issue 2948

Does it take more energy to cycle up a hill or to push your bicycle up?

This question shows how an everyday decision can be tricky to analyse scientifically. It also seems to show that our intuition is poor on matters of energy and power. Of our 500 respondents, 33 per cent thought cycling would use more energy, 26 per cent chose pushing as the biggest drain, while 17 per cent said both activities would consume the same energy. A further 15 per cent thought the answer would depend on issues not mentioned in the question.

The only way to answer this question with certainty will be through experiment. – Ed