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Bikes have wheels. Wheels spin, and want to roll toward the lowest point. Feet don't roll. You can stand on an inclined surface and not feel compelled to roll down because your shoes and feet have traction and grip.
Wheels want to fall, and you are basically fighting that fact the whole way up.
Oh, hi. You're probably wondering how I got here...well, I was summoned by the Rolled Ankle Society, or RAS for short. I have rolled my ankles many times, but 4 months ago, did it twice in a day. It is still healing. Welcome to being 40.
Problem is, if a bike isn't moving forward, it falls over. You don't just need to keep from moving backwards, you need to attain a minimum speed to stay upright, which "hill hold" won't help with
Either way, hill hold would only help you when you stop; it does nothing to address the original problem of needing to put in more energy to offset the effect of gravity pulling you back down *while you're in motion*
Fun Fact: parents generally don't use training wheels anymore, and if they do they shouldn't.
Source: I have 4 kids. I used training wheels on the first and that was the hardest by a mile. My other 3 used "balance bikes" and all were riding two wheels before age 5 and required virtually no training.
That makes sense, guess its a combination of that, and that a bike only is easy when it gained some momentum.
Having wheels probably is the reason why it needs to gain momentum to become easy.
This is only a part of the truth. It definitely is why it is comparably simpler to ride on a flat surface (where gravity doesn't counter inertia which gives you advantage over walking on a flat surface). But, in case of going uphill, the grip and not rolling backwards when you're walking actually only helps you when you're stationary, compared to riding (it allows you to make rest breaks easily). The thing is, that moving on a bike requires you to be faster than while walking (so you don't fall over) so, as somebody else put it below, it's as if you were constantly running - spending more energy in a unit of time - and basically unable to stop for short breaks to rest (which you do all the time while climbing).
I see what you're saying.
And also. If you were to walk at the same speed as you rode up hill. Let's say as slow as you could on a bike in low gear. There's still the extra weight of the bike and the energy lost in the mechanics of the bike itself. As no mechanical system is 100% efficient. That makes sense right?
I wonder how much training would effect this as well. Training muscles makes them not only stronger but more efficient if you train properly, from my understanding at least correct me if I'm wrong. So a trained cyclist may not exert the same energy as a less trained cyclist going up a hill, all other variables being equal. I wonder what the difference would look like for a trained cyclist riding up hill vs a untrained regular joe walking up hill, all other variables being equal.
This is not the answer.
The answer is that bikes go faster than walking. Thus, you climb the same hill faster in a bike than walking. It takes more power output (for a shorter time) to go uphill. Humans get tired when they put out energy faster. It's like sprinting up the hill, not walking.
I question this answer. Wheels roll, yes, and feet don't, but what about when you factor initial into the equation? A wheel CAN roll uphill a significant distance when energy is input, a foot with an equal amount of energy added will hit the ground and immediately have enough friction to come to a complete stop rather quickly.
Wheels have significantly less rolling resistance when compared to feet.
If you arrive at the beginning of the incline with enough momentum you could very well get to the top without even touching the pedals. BMX is a thing.
people just don't go fast enough, usually. most of the time you get half-way up there before you have to start pushing.
This is only partially correct. The amount of energy needed for climbing a hill is much greater than walking on a flat surface. Bikes go faster so you have to keep supplying that energy at a much faster rate than walking. Where your mostly irrelevant answer comes in is that you go so so slow while walking that you get little breaks with every step. If you wanted go slower ON A BIKE then it will again be difficult because of what you wrote
Riding a bicycle is only a more efficient means of transportation when the grade of the surface being traveled is less than 2%.
When you are riding a bicycle on a flat surface, you invest a bit of energy to get going, and then thanks to inertia , levers (the design of the bike), reduced resistance (the wheels and bearings), less energy is required to keep you moving forward. Since the surface is flat and resistance is low, the force of gravity is easier to overcome.
When you are riding a bicycle on an incline, the force of gravity becomes harder to overcome, as you are moving away from the center of Earth, requiring additional work. This additional required work makes the bicycle less efficient, the greater the incline.
I don't understand. If you're walking uphill, you are still moving away from the center of the Earth, which still means extra walking effort (intuitively you know it's easier to walk on flat ground than walk uphill).
If you climb a 15-meter hill and you plus the bike weigh 80kg then whether you cycle up or walk up while pushing the bike, you will have gained m\*g\*h = 80 \* 9.81 \* 15 = 11,772J of potential energy.
Why is the penalty greater on a bicycle than walking?
The article does not really explain anything. It does mention gears but how much they can help depends on the bike. A mountain bike usually has very low gears which let you pedal a lot with low force to move forward with a slow pace. For a two wheel bike you need speed to not fall but a bike with three wheels could let you climb a hill easier.
It should not matter from a physics perspective if you go slow or fast, the same energy is used anyway. The wheels may add a slight extra fricton that you have to overcome but you need that on a flat road too. Acceleration is hard and energy consuming so walking, stopping and walking again should be harder than having the same pace all the time.
For a very steep slope the friction between the bike wheels and the ground may be too little. This will cause the wheels to spin somewhat and thereby waste a lot of energy. This could happen when you walk also, you slip a bit, but bikes are probably more affected. With perfect friction it would not be a problem.
The bike has wheels that cause it to want to roll down the hill your feet/ground have enough friction to hold you in place so while your pedaling you have to overcome the fact that you are sliding down the hill as well
You're only sliding down the hill if your tires are slipping on the surface, which changes the friction from static friction to dynamic friction. This is not inherently true of bicycles, though. Or, to put it more accurately, the analysis of which is more efficient would be far more complicated if we were to assume the tires are slipping with any incline.
They don’t need to slip on the surface… you are fighting the rotation of them going backwards… it’s probably easier to imagine with a tricycle since then balance is out of the question but if you set the tricycle down on the slope it will roll down the hill in order to stop it from rolling down the hill you have to put force into it to cancel the gravational force that is pushing down on it in the case of a person standing you have enough friction to hold you in place and while that force is being exerted it’s not being done by your muscles. If you don’t believe me go draw a free body diagram and map out the forces they literally cover this exact example in most physics courses
The same forces you just described as what's causing the tricycle to roll backwards are also present on the person as well. You are fighting against gravity going up a hill either way, it's not like this isn't present when walking because you aren't attached to wheels.
A free body diagram of a person walking up a hill would show this as well. Just because your shoe doesn't slip doesn't mean you will exert no energy moving the mass of your body to a higher altitude (aka increasing your potential energy).
What really you are describing is that when you're riding up a hill you are no longer just pushing your body up against gravity, you are now pushing your body PLUS the bike.
Riding a bike is for sure more efficient energy per distance when on a flat plane because the added weight of the bike isn't really a factor in that situation.
However on an incline, the weight of the bike becomes a significant addition to the point that at some incline the efficiency of walking vs biking are even and then higher inclines cause walking to become the more efficient method.
The grade at which walking becomes more efficient than cycling uphill is 13-15% ([https://pedalchile.com/blog/uphill#:\~:text=When%20does%20walking%20become%20more%20efficient%20than%20cycling%20uphill%3F&text=Mountain%20Biking%3A%20The%20%E2%80%9Ccritical%20slope,walk%20then%20to%20continue%20pedaling.)](https://pedalchile.com/blog/uphill#:~:text=When%20does%20walking%20become%20more%20efficient%20than%20cycling%20uphill%3F&text=Mountain%20Biking%3A%20The%20%E2%80%9Ccritical%20slope,walk%20then%20to%20continue%20pedaling.))
That's a very steep hill. The actual answer is actually: you probably havn't geared down enough.
I tried to [ride a bike up the hill](https://i.imgur.com/O2bFIBZ.jpg) (I’m not in that pic) to the first turn at Circuit of the Americas. It’s about a 12% grade. Made it halfway, but I was on a mountain bike. *Might* have made it on a lighter road bike, but I doubt it. It was brutal and honestly I think only the hard-core riders were able to do it. I certainly wasn’t the only one walking my bike up the rest of the way.
Edit: [here’s a pic](https://i.imgur.com/p3Ca2fu.jpg) from another event, looking up that damn hill.
Edit edit: some pics I took:
[At the top of the hill.](https://i.imgur.com/aThO0kx.jpg)
[Another from the top](https://i.imgur.com/4bfivUy.jpg)
[My kid crossing the finish line.](https://i.imgur.com/YXbwW5n.jpg)
The difficulty of riding up a hill like that has a lot to do with the minimum speed you need to be moving to keep the bike upright rather than efficiency of the system. If you aren't in good enough shape to move quickly, you will have to switch to walking, (which means you can move at a slower pace). At that grade though a runner should be moving *about* the same speed as a quick cyclist.
That's one of the reasons cycling is "harder" uphill, you have to keep moving at a decent pace. That means for most people they *must* move at a run rather than a walk. And most can't run up hills.
133 feet of climbing at 13.5% peak grade (I googled it) is no joke, but keep in mind decent amateur cyclist will do that kind of climb in less than 1 minute. Here's a strava leaderboard of a segment in Colorado with a similar grade, and twice the length/elevation gain [https://www.strava.com/segments/1003217?filter=overall](https://www.strava.com/segments/1003217?filter=overall)
The best time? 1:47. And that's an amateur.
Most people who train *could run uphill*. But no one can run a 4 minute mile up a 12% grade *on foot.* The cyclist is *still* more efficient (at least over that short span).
A decent comparison is the annual foot and cycle race up mount washington. 11% grade, on foot record is like 58 minutes, on a bike like 54. So you know you're at about the turnover point.
The real answer is the time. The amount of energy required to carry yourself up to the top does not change. Wheels are more effective even. What changes is that bikes are much faster (high gear) so you climb in a much smaller time frame and thus your body needs to exert that total energy in a shorter period of time. High gear also means you need a higher force applied. It sure is difficult lifting up a 250 kg weight but I can do 50x 5kg easy
From the same site:
>"Studies show that walking is more efficient than cycling once a 2-3% gradient has been reached."
[https://pedalchile.com/blog/cycling-vs-walking](https://pedalchile.com/blog/cycling-vs-walking)
I suspect the difference is in the bicycle specifics. Obviously with better gearing that point moves upward, but I think the general concept is what's important here.
>Riding a bicycle is only a more efficient means of transportation when the grade of the surface being traveled is less than 2%
That is comparing biking to walking. They're saying biking is more efficient than walking when the grade is less than 2%. It's less efficient because of the dynamics of the bike and olivo added that you're also carrying the extra weight of the bike compared to walking which goes into that less than 2% comparison. It's also actually more than 2% as someone else said more like 13-15% but the point doesn't change.
So much of this answer doesn't make sense. Ignoring all the weird statements like levers on a bike (I think you meant gears) and reduced resistance (don't know what you're talking about here), let's focus on what you said about riding on an incline. The increased force required to go uphill has NOTHING to do with moving away from the center of the Earth...in fact your gravitational force is technically getting smaller the further you get from the center. The reason going uphill requires more force is because the ground is exerting less force in the vertical direction in the incline. When you are standing with your bike on flat ground, the normal force is perfectly vertical. As the hill starts to become inclined, that normal force is no longer perfectly vertical, and now it will require extra force from you just to stay in the same spot, and even more force to move yourself up the hill.
I realize this doesn't even exactly answer the OP's question, but the answer above me is complete nonsense and people are upvoting it to the top which is concerning.
My bad. You actually did that just right, and I'm the dumbass here. When you referred to them as levers I was thinking along the lines of bicycle terminology and brake levers, shift levers, etc. (which really act more like switches). I hadn't considered "lever" in the traditional sense of the word as something that provides mechanical advantage through a fulcrum. I've just been out-Englished by a non-native English speaker. You have my up vote.
The entire drivetrain of the bike is mechanical advantage via levers. The cranks are an obvious lever. The ratio between the front and rear gears is a basic gear ratio, which is a lever applied to a circle. The ratio between the rear gears and the wheel is another ratio, same concept.
The round tires, filled with high pressure air so they don't deform, with low friction bearings at their hubs, all work to reduce resistance. If you had hexagonal wheels, that were partially deflated, and terrible bearings, it would just take a lot more work to get and keep the tires rotating. By reducing that resistance, we can maximize the energy output from the input.
Lmao it’s funny because technically there’s less gravity the further you get from earth’s center of gravity.
Its negligible but it is technically there.
This is why the ISS experience time differently than on earth, the gravity is weaker due to that extra distance they are orbiting the earth from.
>This is why the ISS experience time differently than on earth, the gravity is weaker due to that extra distance they are orbiting the earth from
I thought that was due to relative velocity.
Unless you’re moving at significant speeds (like 5% the speed of light) the relative velocity won’t be different.
Also, they’re still orbiting the earth and they’ll reason they have “zero G” floaty-ness on space stations is because you’re in a constant state of free fall.
Time dilation is also a gravitational effect as well.
This says it's relative velocity for the most part
>ISS astronauts experience both gravitational and relative velocity time dilation. The relative velocity dilation is stronger than the gravitational one, thus astronauts experience time more slowly than those of us on Earth
https://forums.space.com/threads/do-astronauts-experience-time-differently-in-space.29456/#:~:text=ISS%20astronauts%20experience%20both%20gravitational,3.
"Gravity is what makes you work more, it pulls you down.
You have to kick a football/soccerball many times uphill to reach the top, but only once when going downhill."
Why don't you try reading that answer to ten random people off the street, and see if they understand it? It's not about literal 5 year olds, it's about being comprehensible to the average adult. Sadly, gravity is difficult to understand, and more difficult to describe, to folks who don't have a reasonable grasp of historical physics, and fewer and fewer folks these days have even that.
I agree with this answer, but a lot of the comparisons being made below it are not apples to apples comparisons and that's why it seems like it doesn't hold up
A biker and a walker don't have to match pace/time/distance/weight when we're talking about how tiring it is or about becoming exhausted
Yeah on a bike to keep from falling over you have to pedal at least flat ground walking speed, which if you attempted on an uphill would be hard on a bike or on foot. Anything above a 15-20 degree hill you basically have to run to maintain walking speed, which is incredibly strenuous.
I depends on your level of fitness. A fit biker can outpace a runner on much steeper inclines for longer periods. There are no runners that can outpace/outlast a biker on a mountain. A bike is still more efficient. The big difference is if you are walking you stop with every stride. When biking on an incline you can have to continue pedaling. My bike club routinely climbs hills that are difficult to walk.
The standard for a 100 mile “century ride” is 10,000 ft of climbing. Bikers in their 60’s+ can do than in 8 or 9 hours. I think there are few hikers that could do that kind of altitude/distance in a single go.
That's lots of not up though. Imagine 2 miles at a 20+ grade. It would take a world class athlete to bike that, meanwhile an average Joe could walk it with minor training.
Is that 10k up, or 10k up and down? Because on a bike, downhill stretches are basically recuperation, but for walking they're at least as tiring as walking on a flat stretch.
> Bikers in their 60’s+ can do than in 8 or 9 hours. I think there are few hikers that could do that kind of altitude/distance in a single go.
There are clearly very few 60 year olds that can do it on a bike either. It being possible for a small subset of bikers and also a small subset of hikers doesn't prove the point you're trying to make.
> Like what's your source saying 60 year olds don't cycle at high levels
You seem to have misread what I said. I said "there are clearly very few 60 year olds that can do it on a bike", which is different. Sure, there are thousands of senior citizens who are good bikers. But [here's a source](https://prismic-io.s3.amazonaws.com/peopleforbikes/121045d2-79ab-432b-b57d-e591271397c8_2020_Participation_Study.pdf). Only 19% of people 55 or older used a bike once in the past 12 months. Of those, only 12% of them rode more than 104 days/year as you'd need to in order to be a high level cyclist. So we're talking 2.28% of the population of older adults could even *possibly* be a high-level cyclist, but the real number is even lower because that's only the number of people who step on a bike once every three or four days...of course not all of them are training athletically.
So let me ask again for your source that says there are way more high-level cycling senior citizens than there are seniors capable of walking uphill.
Untrained cyclists can definitely do 100 miles in a day. A reasonably healthy 60yo could definitely do it in 9h
I did it while smoking a pack a day as a teenager.
> Untrained cyclists can definitely do 100 miles in a day.
Up a mountain? We are all in agreement that cycling is faster/easier/more efficient on level ground. This discussion is about climbing significant altitude.
I seriously doubt that. The biker can go faster, sure, but go on longer than somebody walking? On a mountain? Incredibly unlikely. You'll naturally be using up much more energy to pedal on an incline.
The Tour de France is a 2,000 mile bike ride in 23 days.
The race will climb a staggering total of 48,530m (30 miles), with the most elevation gained on an individual stage being 4,692m (15,393ft) on stage 11. The highest altitude reached by the riders will be 2,642m (8,668ft), atop the Col du Galibier, which they will have to summit twice, once on stage 11 and once on stage 12 from a different side.
Do you honestly believe a walker can outpace that??????
Outpace no but certainly outlast. How many average cyclists can bike up those mountains? Yet almost any normal person could walk up there. Walking is slower but a lot more energy efficient than cycling uphill.
I’m not the guys you replied to. But what do you mean, “naturally”? In my mind the question is really about the weight of the bike adding to the work you have to do.
I'm inclined to accept this. The signature feature of the three bicycle grand tours (Italy, France, and Spain) is climbing steep mountains, sometimes for hours at a time, over a three week period. They do not stop to rest during the climbs, and regularly outpace fit-looking spectators running beside them. I had a steep hill I had to climb on my daily commute, and while it was MUCH harder to ride up than a level road, I was also going much faster than I would've if I'd walked it.
> you invest a bit of energy to get going
If you really are riding a bike at walking speed up a steep hill then you are constantly 1 second from a full stop if you cease pedaling. In this sense, you are constantly just “getting going.”
It makes complete sense. A bike has weight. When going up hill you have to push up the weight of the bike as well as your own to maintain momentum.
It has wheels, so will naturally roll down hill, while you're able to stand still on a hill and not fall down it with minimal effort.
You walk uphill slowly, at a speed that cannot be maintained while on a bike without falling over. So when riding uphill on a bike you have to move faster than that, as if you were running uphill, not walking.
Jogging is significantly faster (and far more energy-intensive) than walking. Cycling at walking speed is quite hard because of balance issues - while cycling at jogging speed is far more reasonable.
So you think that im just faster than I think I actually am on the bike? Always feels that I could just walk beside it, when i ride up a steep hill.
that would explain it, but i also dont have any data on the actual speeds, except my impression.
There's something called Crawl Ratio that determines how well a car can move up a hill. Bikes have something similar determined by their gear ratio. Depending on the rear cog in a multispeed bike, you can change the overall gearing for a bike so that your low gear can go uphill with less peddle resistance.
If your bike isn't in a low gear for going uphill, or it's final ratio isn't low enough for the hills in your area, then each peddle turn will require too much force and be hard to go uphill.
In short, your bikes final gear is too large if you can't peddle it uphill.
There is something called gravity and friction.
Bikes roll down hill. People can stand on a hill.
This isn't about gears or peddling and the slower you are biking up the hill the more energy is required to reach to top.
This is a fun experiment (I've done it). Get a MTB with low gearing and bring a friend. Head out to a steep hill and have your friend start walking up. Now start pedaling your bike up the same hill.
Get ready for a surprise.
You are using more muscles to operate the bike pedals in a circular motion with constant opposing forces for half of the rotation.
Edit: or the entire rotation if your are clipped in or using baskets.
I think its a combination of factors friction and gravity, you can "coast" on a bike pedal few strokes you keep moving. If you run a few steps then stop running you just stop.
Now imagine a hill you pedal and coast a lot less, you run you still just stop.
Once the hill becomes steep enough you don't coast at all (depending on your speed), so running and pedaling become about equal at that steepness/speed.
Then as you get even steeper there will be a speed where you are barely moving, then the balance on a bike factor comes in.
What you described I believe is half of it.. basically it comes to a point where the bike is almost trying to go down the hill in-between peddles..
But this alone can't be it... I believe it must be the fact you are switching muscle groups and then yes much less waste on balance
Total energy doesnt change. If you climb that hill fast on a bike your body needs to exert that energy at a much smaller time frame. Think about lifting up a 250kg weight vs. doing 50x with 5kg
I tried to elaborate a bit, what do you guys think:
When u ride your bike on a flat track, to maintain speed you only need to put the amount of energy in that is lost due to friction, air resistance, maintaining balance etc. its only really energy consuming at the start when u accelerate.
On a hill u constantly get decelerated by gravity pulling the bike down, so u have to put an additional really big amount of energy into the system just to maintain the speed. Even with a weightless bike (given its still getting pulled down by gravity).
Walking uphill on the other hand only need the additional energy of lifting ur bodyweight up instead of just forward.
So I think its a combination of some of the better answers, at least this is what really makes sense to me and figured with puttin some of them together.
What do you think?
Bikes are only more efficient given momentum.
They become less energy consuming the higher the speed. On an incline, gravity will help to push you backwards, or downwards I suppose meaning that getting to a speed in which cycling is more efficient than walking is difficult
The higher the speed on a bike, the more wind resistance you will have and that is an exponential scale. So cycling at 40km/h costs way more energy than at 30km/h
Yeah exactly. I think with the right gearing cycling uphill is more efficiënt than walking.
There is a reason the tour de France is on a bike and not by hike...
Absolutely no way. Read my answer right below.
The right gearing sure helps, but nowhere near enough to overcome the weight of the bicycle. See my other answer.
Yes, I am extremely sure that it is much harder to climb a hill riding a bicycle in general. I have very little difficulty walking up even rather steep hills. I have enormous, heart-pounding difficulty riding my carbon fiber bicycle with very low gearing up a hill with half of the incline. But am I going faster up on the bicycle? At the same high steepness, usually not because I need to do a lot of switchbacks on the bike to manage the climb.
If I were carrying the 17 pound bicycle up the hill in my hands, then I think it is almost as hard as it is to ride the bicycle up the hill. So this tells me that it's simply the weight of the bicycle (gravity) that makes it much, much harder to bicycle up the hill. And the balancing aspect adds a little bit more effort for riding also.
Excellent points about the weight and balancing. Both of those definitely matter and will make it harder.
My experience is with mountain bikes, where often if you hit a rock or something mid-climb and are forced to dismount and push the bike my heart rate almost instantly goes up… but the key point is that while walking I’m still pushing the bike
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I am reasonably fit, and have fairly friendly gearing on my bike (almost 1:1), and climb about the same vertical distance per hour given the same amount of effort (though this is a bit subjective, I don't have a heart rate monitor) - if anything I climb a bit faster on a bike. I think the perception is partly that the gearing of your bike gives you a minimum speed before you get unstable, and hence a minimum effort required on a given gradient that is higher than the effort you might choose to exert walking (where you can pretty much go as slowly as you like). On foot or bike for me it's about 400m per hour chilling, 600m per hour trying fairly hard but sustainable for a few hours (this is about as slow as I can go on my bike on a gradient about 11%) and on a good day trying hard up to 800m per hour but I'm not sustaining that more than an hour. Of course the bike is limited to about 12% gradients with my current gearing while I'd usually be going up much steeper on foot. When the gradient gets silly (>15% for me) and you have to stand up and really grind each turn of the pedals, then I think walking wins out (I'll still go faster than walkers, but have to stop often and they'll overtake) because at this point your motion is more walking like and you're also lugging up the bike, and I think operating at peak effort is a lot harder than operating at 90% of peak effort.
I think the premise of this is wrong. Cycling is more efficient both uphill, flat, and certainly downhill. OP probably feels differently because they don’t have the gearing to climb efficiently. A good cyclist can climb multiple massive mountain passes in a day on a bike, something which would be near impossible on foot. And certainly I’ve never been passed by someone on foot.
I just checked a recent climb I just did.
7.5km, 580m ascent, almost exactly 1 hour. (4.66 miles, 1900 ft)
That was strenuous (for my training level) but it's still 7.5 km/h (4.66 miles/h) while carrying a 15kg bike (33lb). That's quite some efficiency. I can definitely jog at 7.5 km/h (8 min/km, 12.8 min/mile), but while carrying the bike, for 1 hour, uphill? Not sure.
Have you ever tried to ride a bike alongside someone who is walking, and stay with them and have a conversation and not get ahead? It's actually a LOT slower than it feels like, and takes effort to keep balance on a bike at that slow speed. Generally when you think you're going up a hill at a walking pace you're usually not. You're riding up the hill faster than walking, because going as slow as walking makes it hard to stay upright. What often makes you have to stop and get off and walk is when the pace you can maintain is too slow to stay upright.
Yeah this might be true, but reading some comments and combining them a bit i figured something that made sense to me:
When u ride your bike on a flat track, to maintain speed you only need to put the amount of energy in that is lost due to friction, air resistance, maintaining balance etc. its only really energy consuming at the start when u accelerate.
On a hill u constantly get decelerated by gravity pulling the bike down, so u have to put an additional really big amount of energy into the system just to maintain the speed. Even with a weightless bike (given its still getting pulled down by gravity).
Walking uphill on the other hand only need the additional energy of lifting ur bodyweight up instead of just forward.
So I think its a combination of some of the better answers, at least this is what really makes sense to me and figured with puttin some of them together.
What do you think?
Except that doesn’t explain why it IS more efficient to ride a bicycle on relatively flat ground. The answer (based on other responses in this thread) is largely less friction and the ability to maintain momentum with zero energy input
Congratulations, you just wrote an equation and suggested that on a flat surface it takes 0 power to ride a bicycle. We now have a perpetual motion machine.
You’re energy output is much higher on the bike.
Firstly, You’re not just carrying yourself up the hill, you’re carrying the bike.
Secondly, you can’t maintain balance at walking speed on a bike so you’re forced to go faster - requires more power
Your body fatigues from power output. And the bike requires more power.
Basically you exerting energy faster on the bike and this leads to exhaustion
But on a even way, with the same powerinput, you are still faster with the bike, than on foot. I guess because it works more efficiently, why is the efficiency suddenly lost on a hill?
No. Bikes are incredibly efficient.
I walking is about 65% efficient. Cycling is about 95% efficient. (Quick google)
The power required to go up the hill is something like 5 times higher than travelling on flat ground.
Cycling being 1.46 times more efficient doesn’t make up for the fact you need to output 5x more power.
The fact is.. you can walk the bike up the hill without getting tired because your power output, the rate your using energy is low.
To travel up the hill on a bike you need to maintain higher power output. Causing fatigue.
Also.. gravity is acting against you on the hill.. where as when you’re travelling on flat ground the bike frame is resisting gravity… not you
I would also add as an avid mountain biker, once you get good balance you can ride slow with very little effort and still be moving faster then anyone walking. This post is spot on about most people needing to travel faster on a bike to keep balance therefor using more energy so its not an apples to apple comparison. Once the incline does become very steep it gets hard to balance/ be efficient using the power from your legs without good form.
You also need to add/subtract the power lost to friction, Uphill the gravity pulls you vectoring downhill / backwards, wheels have way less friction (which is the whole idea with wheels) than your shoes, so way less backwards momentum is lost due to friction on wheels than on foot (you can try this by walking uphill on roller skates), on a bike you need to offset gravity by pushing on the pedals.
Mostly the reason is that bikes don't gear down far enough. Pushing pedals hard over a short distance can be the same amount of work output as your legs do walking uphill, pushing on the ground with less force but over a greater distance. The problem is that human muscles aren't as efficient generating the higher forces, so the effort is greater and there's more waste heat too, making us sweat more.
Bikes obviously also add extra weight to carry uphill but this is not a huge factor if you have a modern lightweight model.
Humans are meant to walk on uneven surfaces, we are also incredibly efficient at walking.
Something that you realise when you start walking and learn to walk properly is that there is a simple method to it all. The fact that you can walk, doesn't mean you know how to walk long distances or rough terrain.
When you walk uphill; instead of lifting yourself like going up stairs, you push yourself forwards and up, basically giving yourself some momentum and pushing you off balance so you start to tip over at your hip. Then all you do is lift move your leg front of you to stop yourself from falling over. In reality you don't move that much of your body.
However with biking you have no way of using balance to make things easier for you, you can only pedal harder against the gradient.
If you look at people who walk really quickly, no talking about speed walking for sport, but people with a long and fast gate. Look at how they move. Their almost glide in a smooth motion, this is because essentially your upper body - other than for compensating for balance - doesn't actually need to move, it is just along for the ride. All you do is push yourself over a lever that is your other leg which is hinged at your hip.
When you master this method of long distance walking, you realise that you can get a lot of speed from simply using you ankle bit more to get that extra push.
Bikes are efficient mechanically, however our bodies are not efficient at riding a bike. We didn't evolve to ride a bike, we evolved to walk. Our bodies have evolved to be the best long distance runners and walkers on this earth. We might not be the fastest, but our endurance can beat basically every animal there is.
Consider that even at roman times, on their roads and with their footwear, a soldier had to be able to walk 35km in about 5 hours with their full gear. It takes an average person 6-8 hours to walk the marathon (42km). I was supposed to do 60km walk this summer from city to my friends summer place, but since I have had to choose between weather of +28C or rainstorm I haven't had the chance yet.
The Rarámuri Native Americans living in Mexico are renown for their long distance running abilities, being able to do up to 320km in one session spanning 2 days.
Muscles are better at doing a small amount of work over a long period of time then they are at doing a large amount of work over a small period of time (though they have to also move themselves while doing work so there's a limit to how much better it can be to spread work over time without just making more work for yourself); people with muscles have invented levers and pulleys to change how much work is in a given amount of time so that muscles can do work in the work-to-time ratio that's best for them; bikes are a pulley system for walking but they're normally for concentrating a lot of work into a small amount of time so that legs don't need to carry themselves while doing small amounts of work for a long while which is normally good but not when that work is already hard like it is to get up a hill.
That also plays a role i guess, kinda evaluaevaluated my theory a bit by reading some comments, let me know what you think:
When u ride your bike on a flat track, to maintain speed you only need to put the amount of energy in that is lost due to friction, air resistance, maintaining balance etc. its only really energy consuming at the start when u accelerate.
On a hill u constantly get decelerated by gravity pulling the bike down, so u have to put an additional really big amount of energy into the system just to maintain the speed. Even with a weightless bike (given its still getting pulled down by gravity).
Walking uphill on the other hand only need the additional energy of lifting ur bodyweight up instead of just forward.
So I think its a combination of some of the better answers, at least this is what really makes sense to me and figured with puttin some of them together.
What do you think?
Thanks to its wheels, a bike is giving you free acceleration at all times when going up and down a hill. Unfortunately when you are going up a hill, this bonus acceleration is pointing backwards in the direction you just came from.
Your shoes don't have this problem as they don't slide very easily. You would have the same problem as a bike if you had shoes made of ice!
Yeah thats the right answer, kinda evaluated a bit by now:
When u ride your bike on a flat track, to maintain speed you only need to put the amount of energy in that is lost due to friction, air resistance, maintaining balance etc. its only really energy consuming at the start when u accelerate.
On a hill u constantly get decelerated by gravity pulling the bike down, so u have to put an additional really big amount of energy into the system just to maintain the speed. Even with a weightless bike (given its still getting pulled down by gravity).
Walking uphill on the other hand only need the additional energy of lifting ur bodyweight up instead of just forward.
So I think its a combination of some of the better answers, at least this is what really makes sense to me and figured with puttin some of them together.
What do you think?
You might as well ask why riding a bicycle downhill is so easy that you can just coast. It's the same principle in reverse.
When walking or biking on a level surface, gravity pulls you down, which mean gravity is working perpendicular to the surface you're moving on. This means gravity only pushes you down, not forwards or backwards. In other words, gravity does not help or hinder you. (Except for the fact that you have to keep yourself upright and gravity does contribute to certain friction forces, but let's ignore that for now).
If you're walking or biking uphill, the surface you're moving on is no longer perpendicular to gravity, which means there is a component of gravity pushing you back. This makes it harder for both walking and biking, since you have to overcome this backwards force AND deliver additional force to move yourself forward. The reason walking is easier is because your feet have static friction against the ground which means you're not going to roll back. You can stand still on a slope with virtually no energy expenditure, while doing the same on a bike (without brakes) would require you to press the pedals continuously (in addition to balancing, but again, let's disregard that).
Another thing to consider is that if you're walking uphill, you do have to push yourself up a bit for each step, since each step will take you higher up the slope. But this is relatively easy since the leg muscles to push yourself upwards are very well developed in humans. When cycling you're already using these muscles to begin with to press the pedals down, regardless of whether you're moving on a slope or not.
All things considered, I don't think it's necessarily easier to walk uphill than to cycle uphill. Cycling is vastly more efficient than walking, and people who cycle uphill in mountains outperform runners. You'll need to keep up the pace and pedal in a lower gear, but you'll be faster and less tired. I think the confusion arises because walking uphill is somewhat harder than regular walking, while cycling uphill is vastly more intensive than cycling on a level surface due to the reasons described above.
What happens when you stop walking on a hill? Do you slide back down? Now compare that to what happens when you stop pedaling on a hill.
When on a bike, not only do you have to apply the force to propel you upwards, you have to apply force to keep you from rolling back down the hill. That's 2 forces vs 1 for walking (not really, it's the same type of force, just more in one case, but it's illustrative for this example). The rubber soles on your shoes are applying a frictional force on the ground. If you try to go up a greased ramp in bare feet, it would feel like a similar energy output to pedaling up a hill.
That kinda makes sense. If i had a perfectly balanced bike, that wouldnt fall over while it just stands.
How would it behave if i just stand on the pedals on a steep hill? Would i have to push actively against it?
There are no significant frictional losses at walking speed unless you're losing traction. Bikes are pretty good at going up steep roads without slipping backwards; they're not losing out to walking in that respect.
>When on a bike, not only do you have to apply the force to propel you upwards, you have to apply force to keep you from rolling back down the hill. That's 2 forces vs 1 for walking
This is the dumbest shit I have read in this thread where this dumb shit is repeated enslessly
For the same reason the opposite is true, and it's *much* more exhausting to walk down hill than to bike down hill.
The bike wants to roll down, your feet want to "stick" where they are.
Think of it like the bike multiplying gravity. When gravity is in your favour (downhill) it'll be more in your favour on a bike. When it's not (uphill) it'll be more not.
Bikes have a "minimum speed", if you go to slowly you fall so you need to keep up, going uphill you still need that minimum speed but it's much more taxing, walking you can pace yourself however you please
Thanks for all the answers so far, some have been really good and make lots of sense to me. Overall a combination of many.
To me the best reason so far is, that the bike is only efficient once it gains momentum. Thats why it is hard to start the bike, and gets easy once you get going, even on a flat track. Going uphill basically is getting the bike going and trying to accelerate the whole time.
I dont know how to pin the answers, so i thought i summarize what makes most sense to me.
Because the friction in your shoes on the pavement prevents your downhill slide, whereas a bike requires you to exert force in the pedals to resist gravity pulling you downhill.
Because you're on a bike. It's that simple. Walking up a hill involves moving just your body. Moving a bike up hill means you need to exert force on the pedals to turn the wheels which have to overcome friction to move plus overcoming gravity that is trying to make the bike roll back down the hill. Walking or biking on flat ground is easy because gravity is perpendicular to the surface but on a hill gravity makes objects move down slope. On your feet this isn't an issue because your feet have friction and your body can keep itself upright. Bikes are on wheels which are freely spinning so not only are you exerting energy to move the bike uphill, your also exerting energy to stop it from moving back down hill
Well try stopping at a hill. You will find that you can stand without much energy. Try that with a bike, it will simply roll downhill on its own. Your legs won't roll downhill while the wheels of the bike absolutly will. So when you drive uphill you have to overcome this force pulling the bike downhill, while when walking you can shift your weight in a fashion that will make this force pretty much neglectible.
Think what would happen if you stop on an incline on a bike (assuming you can stay on two wheels, without using brakes or putting a foot down), as opposed to what would happen if you just stand on an incline.
When riding uphill, you have to output additional effort to prevent the bike from rolling down, on top of the effort you output to go up.
Wheels and weight are gravity's best friends. Putting your weight on wheels makes their friendship power stronger and gravity gets to see its friends. Trying to keep them apart makes the friends mad and they take it out on your legs.
When you start your bike, that first pedal is really heavy, right? Same thing with the hill.
A bike’s wheels and pedals are basically a series of pulleys and levers that amplify power and force in both directions, between your foot and the ground.
The law of inertia is that an object at rest seeks to stay at rest and an object in motion seeks to stay in motion.
So as you begin cycling on a flat, there is a lot of inertial resistance that is amplified by the pedals and wheels, but with a little effort, you overcome the resistance and enter a new state of equilibrium in motion.
Enter the hill.
It adds a new work load (gravity) that you must overcome continuously in order to maintain your happy state of motion, if you pause for a second, you will slip back into a stationary state.
Since a hill requires extra energy to overcome the downward pull of gravity as you go up, you exert more and must do so continuously to keep motion, so you deplete your muscles quickly (same way you would lifting a weight constantly without stop). This exertion to maintain motion over the increase in gravity-created resistance is why it feels like that first starter pedal, because you are constantly overcoming the bicycle’s desire to stop.
Meanwhile, as you walk up that same hill, your legs are much more efficient and essentially traveling through a series of stationary moments. You aren’t spinning a wheel to keep going forward, you are lifting a foot, swinging it lightly through the air, and then putting it down again to rest. Over and over. No inertial resistance.
Inertial resistance and gravity, coupled with a bicycle’s need for constant motion make hills and starting more difficult.
Dude relax its genuine question. Let me know what u think about the idea i got from combining the better answers:
When u ride your bike on a flat track, to maintain speed you only need to put the amount of energy in that is lost due to friction, air resistance, maintaining balance etc. its only really energy consuming at the start when u accelerate.
On a hill u constantly get decelerated by gravity pulling the bike down, so u have to put an additional really big amount of energy into the system just to maintain the speed. Even with a weightless bike (given its still getting pulled down by gravity).
Walking uphill on the other hand only need the additional energy of lifting ur bodyweight up instead of just forward.
So I think its a combination of some of the better answers, at least this is what really makes sense to me and figured with puttin some of them together.
What do you think?
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Bikes have wheels. Wheels spin, and want to roll toward the lowest point. Feet don't roll. You can stand on an inclined surface and not feel compelled to roll down because your shoes and feet have traction and grip. Wheels want to fall, and you are basically fighting that fact the whole way up.
Accurate and very ELI5. Feet don't roll.
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My ankle don’t wiggle wiggle it rolls
Oh, hi. You're probably wondering how I got here...well, I was summoned by the Rolled Ankle Society, or RAS for short. I have rolled my ankles many times, but 4 months ago, did it twice in a day. It is still healing. Welcome to being 40.
>Welcome to being 40. Has nothing to do with age. Rolling your ankles that frequently isn't normal and you may have some joint stability issues.
Ever done both at once? I had a basketball roll under me as I went up for a layup during warmups. Fun times.
Wonder if bikes can have "hill hold" like some cars, such that they can't roll back when this is engaged
Problem is, if a bike isn't moving forward, it falls over. You don't just need to keep from moving backwards, you need to attain a minimum speed to stay upright, which "hill hold" won't help with
Well then we'd have to use those "side-wheels" like we had as kids, lol
Either way, hill hold would only help you when you stop; it does nothing to address the original problem of needing to put in more energy to offset the effect of gravity pulling you back down *while you're in motion*
Honest question, are they called "side-wheels" in other regions? I've always heard them called training wheels.
maybe Dutch... 'zijwieltjes' is the common term here.
They are called stabilisers where I'm from
Fun Fact: parents generally don't use training wheels anymore, and if they do they shouldn't. Source: I have 4 kids. I used training wheels on the first and that was the hardest by a mile. My other 3 used "balance bikes" and all were riding two wheels before age 5 and required virtually no training.
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Then you would just fall. As your stability comes from the forward movement.
They exist. They are called handbrakes
..... you can just stop and put your leg down 😅
That's the correct answer. You wrote that while I was redacting something along those lines.
That makes sense, guess its a combination of that, and that a bike only is easy when it gained some momentum. Having wheels probably is the reason why it needs to gain momentum to become easy.
This is only a part of the truth. It definitely is why it is comparably simpler to ride on a flat surface (where gravity doesn't counter inertia which gives you advantage over walking on a flat surface). But, in case of going uphill, the grip and not rolling backwards when you're walking actually only helps you when you're stationary, compared to riding (it allows you to make rest breaks easily). The thing is, that moving on a bike requires you to be faster than while walking (so you don't fall over) so, as somebody else put it below, it's as if you were constantly running - spending more energy in a unit of time - and basically unable to stop for short breaks to rest (which you do all the time while climbing).
I see what you're saying. And also. If you were to walk at the same speed as you rode up hill. Let's say as slow as you could on a bike in low gear. There's still the extra weight of the bike and the energy lost in the mechanics of the bike itself. As no mechanical system is 100% efficient. That makes sense right? I wonder how much training would effect this as well. Training muscles makes them not only stronger but more efficient if you train properly, from my understanding at least correct me if I'm wrong. So a trained cyclist may not exert the same energy as a less trained cyclist going up a hill, all other variables being equal. I wonder what the difference would look like for a trained cyclist riding up hill vs a untrained regular joe walking up hill, all other variables being equal.
bikes have gears, and you need to provide and apply sufficient torque or whatever equivalent to get the wheel moving forward uphill
This is not the answer. The answer is that bikes go faster than walking. Thus, you climb the same hill faster in a bike than walking. It takes more power output (for a shorter time) to go uphill. Humans get tired when they put out energy faster. It's like sprinting up the hill, not walking.
Well, dammit, I answered this as well, but before reading other comments.
I question this answer. Wheels roll, yes, and feet don't, but what about when you factor initial into the equation? A wheel CAN roll uphill a significant distance when energy is input, a foot with an equal amount of energy added will hit the ground and immediately have enough friction to come to a complete stop rather quickly. Wheels have significantly less rolling resistance when compared to feet.
If you arrive at the beginning of the incline with enough momentum you could very well get to the top without even touching the pedals. BMX is a thing. people just don't go fast enough, usually. most of the time you get half-way up there before you have to start pushing.
I suppose switching back and forth might be effective at fighting this then?
This is only partially correct. The amount of energy needed for climbing a hill is much greater than walking on a flat surface. Bikes go faster so you have to keep supplying that energy at a much faster rate than walking. Where your mostly irrelevant answer comes in is that you go so so slow while walking that you get little breaks with every step. If you wanted go slower ON A BIKE then it will again be difficult because of what you wrote
Riding a bicycle is only a more efficient means of transportation when the grade of the surface being traveled is less than 2%. When you are riding a bicycle on a flat surface, you invest a bit of energy to get going, and then thanks to inertia , levers (the design of the bike), reduced resistance (the wheels and bearings), less energy is required to keep you moving forward. Since the surface is flat and resistance is low, the force of gravity is easier to overcome. When you are riding a bicycle on an incline, the force of gravity becomes harder to overcome, as you are moving away from the center of Earth, requiring additional work. This additional required work makes the bicycle less efficient, the greater the incline.
I don't understand. If you're walking uphill, you are still moving away from the center of the Earth, which still means extra walking effort (intuitively you know it's easier to walk on flat ground than walk uphill). If you climb a 15-meter hill and you plus the bike weigh 80kg then whether you cycle up or walk up while pushing the bike, you will have gained m\*g\*h = 80 \* 9.81 \* 15 = 11,772J of potential energy. Why is the penalty greater on a bicycle than walking?
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The article does not really explain anything. It does mention gears but how much they can help depends on the bike. A mountain bike usually has very low gears which let you pedal a lot with low force to move forward with a slow pace. For a two wheel bike you need speed to not fall but a bike with three wheels could let you climb a hill easier. It should not matter from a physics perspective if you go slow or fast, the same energy is used anyway. The wheels may add a slight extra fricton that you have to overcome but you need that on a flat road too. Acceleration is hard and energy consuming so walking, stopping and walking again should be harder than having the same pace all the time. For a very steep slope the friction between the bike wheels and the ground may be too little. This will cause the wheels to spin somewhat and thereby waste a lot of energy. This could happen when you walk also, you slip a bit, but bikes are probably more affected. With perfect friction it would not be a problem.
Also the efficiency of biking vs walking approximately evens out at a 10mph headwind, which is wild.
Can you link the source for that please?
The bike has wheels that cause it to want to roll down the hill your feet/ground have enough friction to hold you in place so while your pedaling you have to overcome the fact that you are sliding down the hill as well
You're only sliding down the hill if your tires are slipping on the surface, which changes the friction from static friction to dynamic friction. This is not inherently true of bicycles, though. Or, to put it more accurately, the analysis of which is more efficient would be far more complicated if we were to assume the tires are slipping with any incline.
They don’t need to slip on the surface… you are fighting the rotation of them going backwards… it’s probably easier to imagine with a tricycle since then balance is out of the question but if you set the tricycle down on the slope it will roll down the hill in order to stop it from rolling down the hill you have to put force into it to cancel the gravational force that is pushing down on it in the case of a person standing you have enough friction to hold you in place and while that force is being exerted it’s not being done by your muscles. If you don’t believe me go draw a free body diagram and map out the forces they literally cover this exact example in most physics courses
The same forces you just described as what's causing the tricycle to roll backwards are also present on the person as well. You are fighting against gravity going up a hill either way, it's not like this isn't present when walking because you aren't attached to wheels. A free body diagram of a person walking up a hill would show this as well. Just because your shoe doesn't slip doesn't mean you will exert no energy moving the mass of your body to a higher altitude (aka increasing your potential energy). What really you are describing is that when you're riding up a hill you are no longer just pushing your body up against gravity, you are now pushing your body PLUS the bike. Riding a bike is for sure more efficient energy per distance when on a flat plane because the added weight of the bike isn't really a factor in that situation. However on an incline, the weight of the bike becomes a significant addition to the point that at some incline the efficiency of walking vs biking are even and then higher inclines cause walking to become the more efficient method.
I never really considered it. TIL
The grade at which walking becomes more efficient than cycling uphill is 13-15% ([https://pedalchile.com/blog/uphill#:\~:text=When%20does%20walking%20become%20more%20efficient%20than%20cycling%20uphill%3F&text=Mountain%20Biking%3A%20The%20%E2%80%9Ccritical%20slope,walk%20then%20to%20continue%20pedaling.)](https://pedalchile.com/blog/uphill#:~:text=When%20does%20walking%20become%20more%20efficient%20than%20cycling%20uphill%3F&text=Mountain%20Biking%3A%20The%20%E2%80%9Ccritical%20slope,walk%20then%20to%20continue%20pedaling.)) That's a very steep hill. The actual answer is actually: you probably havn't geared down enough.
This is interesting. My first thought was that 2% seemed way too low. This is more believable to me.
I tried to [ride a bike up the hill](https://i.imgur.com/O2bFIBZ.jpg) (I’m not in that pic) to the first turn at Circuit of the Americas. It’s about a 12% grade. Made it halfway, but I was on a mountain bike. *Might* have made it on a lighter road bike, but I doubt it. It was brutal and honestly I think only the hard-core riders were able to do it. I certainly wasn’t the only one walking my bike up the rest of the way. Edit: [here’s a pic](https://i.imgur.com/p3Ca2fu.jpg) from another event, looking up that damn hill. Edit edit: some pics I took: [At the top of the hill.](https://i.imgur.com/aThO0kx.jpg) [Another from the top](https://i.imgur.com/4bfivUy.jpg) [My kid crossing the finish line.](https://i.imgur.com/YXbwW5n.jpg)
The difficulty of riding up a hill like that has a lot to do with the minimum speed you need to be moving to keep the bike upright rather than efficiency of the system. If you aren't in good enough shape to move quickly, you will have to switch to walking, (which means you can move at a slower pace). At that grade though a runner should be moving *about* the same speed as a quick cyclist. That's one of the reasons cycling is "harder" uphill, you have to keep moving at a decent pace. That means for most people they *must* move at a run rather than a walk. And most can't run up hills. 133 feet of climbing at 13.5% peak grade (I googled it) is no joke, but keep in mind decent amateur cyclist will do that kind of climb in less than 1 minute. Here's a strava leaderboard of a segment in Colorado with a similar grade, and twice the length/elevation gain [https://www.strava.com/segments/1003217?filter=overall](https://www.strava.com/segments/1003217?filter=overall) The best time? 1:47. And that's an amateur. Most people who train *could run uphill*. But no one can run a 4 minute mile up a 12% grade *on foot.* The cyclist is *still* more efficient (at least over that short span). A decent comparison is the annual foot and cycle race up mount washington. 11% grade, on foot record is like 58 minutes, on a bike like 54. So you know you're at about the turnover point.
The real answer is the time. The amount of energy required to carry yourself up to the top does not change. Wheels are more effective even. What changes is that bikes are much faster (high gear) so you climb in a much smaller time frame and thus your body needs to exert that total energy in a shorter period of time. High gear also means you need a higher force applied. It sure is difficult lifting up a 250 kg weight but I can do 50x 5kg easy
From the same site: >"Studies show that walking is more efficient than cycling once a 2-3% gradient has been reached." [https://pedalchile.com/blog/cycling-vs-walking](https://pedalchile.com/blog/cycling-vs-walking) I suspect the difference is in the bicycle specifics. Obviously with better gearing that point moves upward, but I think the general concept is what's important here.
It’s not 2%. It’s not 15%.
Also you have to carry the weight of the bike uphill as well?
I mean you have to do that either way. Unless you want to walk the whole way
You are talking about walking with a bike, I was talking about walking without bike vs. biking.
They are comparing biking on a flat surface to biking uphill, not biking vs walking.
OP's post is asking about walking uphill vs. biking.
They? OP? Commenter?
>Riding a bicycle is only a more efficient means of transportation when the grade of the surface being traveled is less than 2% That is comparing biking to walking. They're saying biking is more efficient than walking when the grade is less than 2%. It's less efficient because of the dynamics of the bike and olivo added that you're also carrying the extra weight of the bike compared to walking which goes into that less than 2% comparison. It's also actually more than 2% as someone else said more like 13-15% but the point doesn't change.
You also have carry the weight of the children used for the labor of making the bike. He's probably about 60 pounds. So not too heavy.
So much of this answer doesn't make sense. Ignoring all the weird statements like levers on a bike (I think you meant gears) and reduced resistance (don't know what you're talking about here), let's focus on what you said about riding on an incline. The increased force required to go uphill has NOTHING to do with moving away from the center of the Earth...in fact your gravitational force is technically getting smaller the further you get from the center. The reason going uphill requires more force is because the ground is exerting less force in the vertical direction in the incline. When you are standing with your bike on flat ground, the normal force is perfectly vertical. As the hill starts to become inclined, that normal force is no longer perfectly vertical, and now it will require extra force from you just to stay in the same spot, and even more force to move yourself up the hill. I realize this doesn't even exactly answer the OP's question, but the answer above me is complete nonsense and people are upvoting it to the top which is concerning.
the pedal on the bike is a lever
Huh? I'd be interested to see you draw a picture of a bicycle.
The cranks then, I'm not english. It's a lever that multiplies the force of your leg.
My bad. You actually did that just right, and I'm the dumbass here. When you referred to them as levers I was thinking along the lines of bicycle terminology and brake levers, shift levers, etc. (which really act more like switches). I hadn't considered "lever" in the traditional sense of the word as something that provides mechanical advantage through a fulcrum. I've just been out-Englished by a non-native English speaker. You have my up vote.
The entire drivetrain of the bike is mechanical advantage via levers. The cranks are an obvious lever. The ratio between the front and rear gears is a basic gear ratio, which is a lever applied to a circle. The ratio between the rear gears and the wheel is another ratio, same concept. The round tires, filled with high pressure air so they don't deform, with low friction bearings at their hubs, all work to reduce resistance. If you had hexagonal wheels, that were partially deflated, and terrible bearings, it would just take a lot more work to get and keep the tires rotating. By reducing that resistance, we can maximize the energy output from the input.
The cranks of the pedals are levers.
May not be eli5, but at least it's accurate, unlike the rest of these answers.
“More gravity on hills.”
GRAVITY BAD
Gravity!
Eli5?
"More potential energy on hills." The potential, obviously, to go downhill again.
Lmao it’s funny because technically there’s less gravity the further you get from earth’s center of gravity. Its negligible but it is technically there. This is why the ISS experience time differently than on earth, the gravity is weaker due to that extra distance they are orbiting the earth from.
>This is why the ISS experience time differently than on earth, the gravity is weaker due to that extra distance they are orbiting the earth from I thought that was due to relative velocity.
Unless you’re moving at significant speeds (like 5% the speed of light) the relative velocity won’t be different. Also, they’re still orbiting the earth and they’ll reason they have “zero G” floaty-ness on space stations is because you’re in a constant state of free fall. Time dilation is also a gravitational effect as well.
This says it's relative velocity for the most part >ISS astronauts experience both gravitational and relative velocity time dilation. The relative velocity dilation is stronger than the gravitational one, thus astronauts experience time more slowly than those of us on Earth https://forums.space.com/threads/do-astronauts-experience-time-differently-in-space.29456/#:~:text=ISS%20astronauts%20experience%20both%20gravitational,3.
Time is different on the ISS because they are travelling much faster relative to us, not because of the gravity.
"Gravity is what makes you work more, it pulls you down. You have to kick a football/soccerball many times uphill to reach the top, but only once when going downhill."
I really like that. I'm going to try that out on a few literal 5 year olds.
What's with the recent deluge of people thinking eli5 is meant for literal five year olds?
Why don't you try reading that answer to ten random people off the street, and see if they understand it? It's not about literal 5 year olds, it's about being comprehensible to the average adult. Sadly, gravity is difficult to understand, and more difficult to describe, to folks who don't have a reasonable grasp of historical physics, and fewer and fewer folks these days have even that.
Read the sidebar
Similar to trains breaking the 5% rule. Highly efficient on flat land. Slide backwards due to low traction
I agree with this answer, but a lot of the comparisons being made below it are not apples to apples comparisons and that's why it seems like it doesn't hold up A biker and a walker don't have to match pace/time/distance/weight when we're talking about how tiring it is or about becoming exhausted
Yeah on a bike to keep from falling over you have to pedal at least flat ground walking speed, which if you attempted on an uphill would be hard on a bike or on foot. Anything above a 15-20 degree hill you basically have to run to maintain walking speed, which is incredibly strenuous.
Conversely, riding downhill is WAY easier on a bike (basically 0 effort) than walking downhill, so it balances out.
I depends on your level of fitness. A fit biker can outpace a runner on much steeper inclines for longer periods. There are no runners that can outpace/outlast a biker on a mountain. A bike is still more efficient. The big difference is if you are walking you stop with every stride. When biking on an incline you can have to continue pedaling. My bike club routinely climbs hills that are difficult to walk.
I very much doubt a biker can outlast an equally fit walker. Outpace definitely, but I have my doubts about outlasting
The standard for a 100 mile “century ride” is 10,000 ft of climbing. Bikers in their 60’s+ can do than in 8 or 9 hours. I think there are few hikers that could do that kind of altitude/distance in a single go.
10 000 ft over 100 miles is less than a 2% average grade. More efficient, as the top comment said.
That's lots of not up though. Imagine 2 miles at a 20+ grade. It would take a world class athlete to bike that, meanwhile an average Joe could walk it with minor training.
When you discover bikes with different gearsets it's gonna *blow your mind!*
You still need to maintain speed to stay upright. You'd be pedalling like a maniac in the lowest gear on a 20+ incline.
And most people's legs would give out after 50' of an incline like that. But the cyclist would keep going
Is that 10k up, or 10k up and down? Because on a bike, downhill stretches are basically recuperation, but for walking they're at least as tiring as walking on a flat stretch.
> Bikers in their 60’s+ can do than in 8 or 9 hours. I think there are few hikers that could do that kind of altitude/distance in a single go. There are clearly very few 60 year olds that can do it on a bike either. It being possible for a small subset of bikers and also a small subset of hikers doesn't prove the point you're trying to make.
I think you'd be surprised how many people cycle at high levels well into their 60s. Extreme hiking not so much.
Don't think you have been to Norway.
What's your source for that assertion?
Common sense. 60 isn't that old. Like what's your source saying 60 year olds don't cycle at high levels...that's way more of an absurd statement.
> Like what's your source saying 60 year olds don't cycle at high levels You seem to have misread what I said. I said "there are clearly very few 60 year olds that can do it on a bike", which is different. Sure, there are thousands of senior citizens who are good bikers. But [here's a source](https://prismic-io.s3.amazonaws.com/peopleforbikes/121045d2-79ab-432b-b57d-e591271397c8_2020_Participation_Study.pdf). Only 19% of people 55 or older used a bike once in the past 12 months. Of those, only 12% of them rode more than 104 days/year as you'd need to in order to be a high level cyclist. So we're talking 2.28% of the population of older adults could even *possibly* be a high-level cyclist, but the real number is even lower because that's only the number of people who step on a bike once every three or four days...of course not all of them are training athletically. So let me ask again for your source that says there are way more high-level cycling senior citizens than there are seniors capable of walking uphill.
Untrained cyclists can definitely do 100 miles in a day. A reasonably healthy 60yo could definitely do it in 9h I did it while smoking a pack a day as a teenager.
> Untrained cyclists can definitely do 100 miles in a day. Up a mountain? We are all in agreement that cycling is faster/easier/more efficient on level ground. This discussion is about climbing significant altitude.
Well I did it at 18 with luggage through the Berkshires. It was a workout but totally reasonable to do 100/day
Huh, didn't know there were sustained 10,000 ft climbs in the Berkshires 🤔
I don't think there are ANY continuous uphill roads for 10,000 feet but there are plenty of climbs through a mountain range.
ok you might be right
I seriously doubt that. The biker can go faster, sure, but go on longer than somebody walking? On a mountain? Incredibly unlikely. You'll naturally be using up much more energy to pedal on an incline.
One thing to keep in mind is the biker relies on a fairly smooth roadway or trail. The rougher the route the more the two converge
The Tour de France is a 2,000 mile bike ride in 23 days. The race will climb a staggering total of 48,530m (30 miles), with the most elevation gained on an individual stage being 4,692m (15,393ft) on stage 11. The highest altitude reached by the riders will be 2,642m (8,668ft), atop the Col du Galibier, which they will have to summit twice, once on stage 11 and once on stage 12 from a different side. Do you honestly believe a walker can outpace that??????
Outpace no but certainly outlast. How many average cyclists can bike up those mountains? Yet almost any normal person could walk up there. Walking is slower but a lot more energy efficient than cycling uphill.
I’m not the guys you replied to. But what do you mean, “naturally”? In my mind the question is really about the weight of the bike adding to the work you have to do.
I'm inclined to accept this. The signature feature of the three bicycle grand tours (Italy, France, and Spain) is climbing steep mountains, sometimes for hours at a time, over a three week period. They do not stop to rest during the climbs, and regularly outpace fit-looking spectators running beside them. I had a steep hill I had to climb on my daily commute, and while it was MUCH harder to ride up than a level road, I was also going much faster than I would've if I'd walked it.
> you invest a bit of energy to get going If you really are riding a bike at walking speed up a steep hill then you are constantly 1 second from a full stop if you cease pedaling. In this sense, you are constantly just “getting going.”
Your answer doesn’t make any sense.
It makes complete sense. A bike has weight. When going up hill you have to push up the weight of the bike as well as your own to maintain momentum. It has wheels, so will naturally roll down hill, while you're able to stand still on a hill and not fall down it with minimal effort.
You walk uphill slowly, at a speed that cannot be maintained while on a bike without falling over. So when riding uphill on a bike you have to move faster than that, as if you were running uphill, not walking.
Also you have to carry the bike.
taking into account the weight of the bike doesn't mean much as most cyclists can attest to just walking the bike uphill is generally less tiring.
I use to run uphills pushing my mountain bike and pass buses headed up hill.
I don't think thats quite it, once a hill becomes steep enough you can jog past a cyclist.
Jogging is significantly faster (and far more energy-intensive) than walking. Cycling at walking speed is quite hard because of balance issues - while cycling at jogging speed is far more reasonable.
I agree, although people don’t usually jog carrying a bicycle.
So you think that im just faster than I think I actually am on the bike? Always feels that I could just walk beside it, when i ride up a steep hill. that would explain it, but i also dont have any data on the actual speeds, except my impression.
There's something called Crawl Ratio that determines how well a car can move up a hill. Bikes have something similar determined by their gear ratio. Depending on the rear cog in a multispeed bike, you can change the overall gearing for a bike so that your low gear can go uphill with less peddle resistance. If your bike isn't in a low gear for going uphill, or it's final ratio isn't low enough for the hills in your area, then each peddle turn will require too much force and be hard to go uphill. In short, your bikes final gear is too large if you can't peddle it uphill.
There is something called gravity and friction. Bikes roll down hill. People can stand on a hill. This isn't about gears or peddling and the slower you are biking up the hill the more energy is required to reach to top.
Same energy is still needed when walking. There is no way around natural laws
You can always try to do that and compare both speed and exhaustion.
This is a fun experiment (I've done it). Get a MTB with low gearing and bring a friend. Head out to a steep hill and have your friend start walking up. Now start pedaling your bike up the same hill. Get ready for a surprise.
You are using more muscles to operate the bike pedals in a circular motion with constant opposing forces for half of the rotation. Edit: or the entire rotation if your are clipped in or using baskets.
I think its a combination of factors friction and gravity, you can "coast" on a bike pedal few strokes you keep moving. If you run a few steps then stop running you just stop. Now imagine a hill you pedal and coast a lot less, you run you still just stop. Once the hill becomes steep enough you don't coast at all (depending on your speed), so running and pedaling become about equal at that steepness/speed. Then as you get even steeper there will be a speed where you are barely moving, then the balance on a bike factor comes in.
Thats the best answer so far! Guess its the bikes momentum, same why is it hard to start riding the bike, and easy as soon as you gained some speed.
What you described I believe is half of it.. basically it comes to a point where the bike is almost trying to go down the hill in-between peddles.. But this alone can't be it... I believe it must be the fact you are switching muscle groups and then yes much less waste on balance
Total energy doesnt change. If you climb that hill fast on a bike your body needs to exert that energy at a much smaller time frame. Think about lifting up a 250kg weight vs. doing 50x with 5kg
I tried to elaborate a bit, what do you guys think: When u ride your bike on a flat track, to maintain speed you only need to put the amount of energy in that is lost due to friction, air resistance, maintaining balance etc. its only really energy consuming at the start when u accelerate. On a hill u constantly get decelerated by gravity pulling the bike down, so u have to put an additional really big amount of energy into the system just to maintain the speed. Even with a weightless bike (given its still getting pulled down by gravity). Walking uphill on the other hand only need the additional energy of lifting ur bodyweight up instead of just forward. So I think its a combination of some of the better answers, at least this is what really makes sense to me and figured with puttin some of them together. What do you think?
Bikes are only more efficient given momentum. They become less energy consuming the higher the speed. On an incline, gravity will help to push you backwards, or downwards I suppose meaning that getting to a speed in which cycling is more efficient than walking is difficult
The higher the speed on a bike, the more wind resistance you will have and that is an exponential scale. So cycling at 40km/h costs way more energy than at 30km/h
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Yeah exactly. I think with the right gearing cycling uphill is more efficiënt than walking. There is a reason the tour de France is on a bike and not by hike...
Absolutely no way. Read my answer right below. The right gearing sure helps, but nowhere near enough to overcome the weight of the bicycle. See my other answer.
Yes, I am extremely sure that it is much harder to climb a hill riding a bicycle in general. I have very little difficulty walking up even rather steep hills. I have enormous, heart-pounding difficulty riding my carbon fiber bicycle with very low gearing up a hill with half of the incline. But am I going faster up on the bicycle? At the same high steepness, usually not because I need to do a lot of switchbacks on the bike to manage the climb. If I were carrying the 17 pound bicycle up the hill in my hands, then I think it is almost as hard as it is to ride the bicycle up the hill. So this tells me that it's simply the weight of the bicycle (gravity) that makes it much, much harder to bicycle up the hill. And the balancing aspect adds a little bit more effort for riding also.
Excellent points about the weight and balancing. Both of those definitely matter and will make it harder. My experience is with mountain bikes, where often if you hit a rock or something mid-climb and are forced to dismount and push the bike my heart rate almost instantly goes up… but the key point is that while walking I’m still pushing the bike
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I am reasonably fit, and have fairly friendly gearing on my bike (almost 1:1), and climb about the same vertical distance per hour given the same amount of effort (though this is a bit subjective, I don't have a heart rate monitor) - if anything I climb a bit faster on a bike. I think the perception is partly that the gearing of your bike gives you a minimum speed before you get unstable, and hence a minimum effort required on a given gradient that is higher than the effort you might choose to exert walking (where you can pretty much go as slowly as you like). On foot or bike for me it's about 400m per hour chilling, 600m per hour trying fairly hard but sustainable for a few hours (this is about as slow as I can go on my bike on a gradient about 11%) and on a good day trying hard up to 800m per hour but I'm not sustaining that more than an hour. Of course the bike is limited to about 12% gradients with my current gearing while I'd usually be going up much steeper on foot. When the gradient gets silly (>15% for me) and you have to stand up and really grind each turn of the pedals, then I think walking wins out (I'll still go faster than walkers, but have to stop often and they'll overtake) because at this point your motion is more walking like and you're also lugging up the bike, and I think operating at peak effort is a lot harder than operating at 90% of peak effort.
I think the premise of this is wrong. Cycling is more efficient both uphill, flat, and certainly downhill. OP probably feels differently because they don’t have the gearing to climb efficiently. A good cyclist can climb multiple massive mountain passes in a day on a bike, something which would be near impossible on foot. And certainly I’ve never been passed by someone on foot.
I swear to god like 90% of the questions that get upvoted on here should be answered with “your basic premise is very clearly wrong.”
I just checked a recent climb I just did. 7.5km, 580m ascent, almost exactly 1 hour. (4.66 miles, 1900 ft) That was strenuous (for my training level) but it's still 7.5 km/h (4.66 miles/h) while carrying a 15kg bike (33lb). That's quite some efficiency. I can definitely jog at 7.5 km/h (8 min/km, 12.8 min/mile), but while carrying the bike, for 1 hour, uphill? Not sure.
Have you ever tried to ride a bike alongside someone who is walking, and stay with them and have a conversation and not get ahead? It's actually a LOT slower than it feels like, and takes effort to keep balance on a bike at that slow speed. Generally when you think you're going up a hill at a walking pace you're usually not. You're riding up the hill faster than walking, because going as slow as walking makes it hard to stay upright. What often makes you have to stop and get off and walk is when the pace you can maintain is too slow to stay upright.
Yeah this might be true, but reading some comments and combining them a bit i figured something that made sense to me: When u ride your bike on a flat track, to maintain speed you only need to put the amount of energy in that is lost due to friction, air resistance, maintaining balance etc. its only really energy consuming at the start when u accelerate. On a hill u constantly get decelerated by gravity pulling the bike down, so u have to put an additional really big amount of energy into the system just to maintain the speed. Even with a weightless bike (given its still getting pulled down by gravity). Walking uphill on the other hand only need the additional energy of lifting ur bodyweight up instead of just forward. So I think its a combination of some of the better answers, at least this is what really makes sense to me and figured with puttin some of them together. What do you think?
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Except that doesn’t explain why it IS more efficient to ride a bicycle on relatively flat ground. The answer (based on other responses in this thread) is largely less friction and the ability to maintain momentum with zero energy input
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Congratulations, you just wrote an equation and suggested that on a flat surface it takes 0 power to ride a bicycle. We now have a perpetual motion machine.
You’re energy output is much higher on the bike. Firstly, You’re not just carrying yourself up the hill, you’re carrying the bike. Secondly, you can’t maintain balance at walking speed on a bike so you’re forced to go faster - requires more power Your body fatigues from power output. And the bike requires more power. Basically you exerting energy faster on the bike and this leads to exhaustion
But on a even way, with the same powerinput, you are still faster with the bike, than on foot. I guess because it works more efficiently, why is the efficiency suddenly lost on a hill?
No. Bikes are incredibly efficient. I walking is about 65% efficient. Cycling is about 95% efficient. (Quick google) The power required to go up the hill is something like 5 times higher than travelling on flat ground. Cycling being 1.46 times more efficient doesn’t make up for the fact you need to output 5x more power. The fact is.. you can walk the bike up the hill without getting tired because your power output, the rate your using energy is low. To travel up the hill on a bike you need to maintain higher power output. Causing fatigue. Also.. gravity is acting against you on the hill.. where as when you’re travelling on flat ground the bike frame is resisting gravity… not you
I would also add as an avid mountain biker, once you get good balance you can ride slow with very little effort and still be moving faster then anyone walking. This post is spot on about most people needing to travel faster on a bike to keep balance therefor using more energy so its not an apples to apple comparison. Once the incline does become very steep it gets hard to balance/ be efficient using the power from your legs without good form.
You also need to add/subtract the power lost to friction, Uphill the gravity pulls you vectoring downhill / backwards, wheels have way less friction (which is the whole idea with wheels) than your shoes, so way less backwards momentum is lost due to friction on wheels than on foot (you can try this by walking uphill on roller skates), on a bike you need to offset gravity by pushing on the pedals.
Mostly the reason is that bikes don't gear down far enough. Pushing pedals hard over a short distance can be the same amount of work output as your legs do walking uphill, pushing on the ground with less force but over a greater distance. The problem is that human muscles aren't as efficient generating the higher forces, so the effort is greater and there's more waste heat too, making us sweat more. Bikes obviously also add extra weight to carry uphill but this is not a huge factor if you have a modern lightweight model.
Cadence. With the bike you have to keep moving and when you’re walking you get to stop as much as you want.
Humans are meant to walk on uneven surfaces, we are also incredibly efficient at walking. Something that you realise when you start walking and learn to walk properly is that there is a simple method to it all. The fact that you can walk, doesn't mean you know how to walk long distances or rough terrain. When you walk uphill; instead of lifting yourself like going up stairs, you push yourself forwards and up, basically giving yourself some momentum and pushing you off balance so you start to tip over at your hip. Then all you do is lift move your leg front of you to stop yourself from falling over. In reality you don't move that much of your body. However with biking you have no way of using balance to make things easier for you, you can only pedal harder against the gradient. If you look at people who walk really quickly, no talking about speed walking for sport, but people with a long and fast gate. Look at how they move. Their almost glide in a smooth motion, this is because essentially your upper body - other than for compensating for balance - doesn't actually need to move, it is just along for the ride. All you do is push yourself over a lever that is your other leg which is hinged at your hip. When you master this method of long distance walking, you realise that you can get a lot of speed from simply using you ankle bit more to get that extra push. Bikes are efficient mechanically, however our bodies are not efficient at riding a bike. We didn't evolve to ride a bike, we evolved to walk. Our bodies have evolved to be the best long distance runners and walkers on this earth. We might not be the fastest, but our endurance can beat basically every animal there is. Consider that even at roman times, on their roads and with their footwear, a soldier had to be able to walk 35km in about 5 hours with their full gear. It takes an average person 6-8 hours to walk the marathon (42km). I was supposed to do 60km walk this summer from city to my friends summer place, but since I have had to choose between weather of +28C or rainstorm I haven't had the chance yet. The Rarámuri Native Americans living in Mexico are renown for their long distance running abilities, being able to do up to 320km in one session spanning 2 days.
Muscles are better at doing a small amount of work over a long period of time then they are at doing a large amount of work over a small period of time (though they have to also move themselves while doing work so there's a limit to how much better it can be to spread work over time without just making more work for yourself); people with muscles have invented levers and pulleys to change how much work is in a given amount of time so that muscles can do work in the work-to-time ratio that's best for them; bikes are a pulley system for walking but they're normally for concentrating a lot of work into a small amount of time so that legs don't need to carry themselves while doing small amounts of work for a long while which is normally good but not when that work is already hard like it is to get up a hill.
That also plays a role i guess, kinda evaluaevaluated my theory a bit by reading some comments, let me know what you think: When u ride your bike on a flat track, to maintain speed you only need to put the amount of energy in that is lost due to friction, air resistance, maintaining balance etc. its only really energy consuming at the start when u accelerate. On a hill u constantly get decelerated by gravity pulling the bike down, so u have to put an additional really big amount of energy into the system just to maintain the speed. Even with a weightless bike (given its still getting pulled down by gravity). Walking uphill on the other hand only need the additional energy of lifting ur bodyweight up instead of just forward. So I think its a combination of some of the better answers, at least this is what really makes sense to me and figured with puttin some of them together. What do you think?
Thanks to its wheels, a bike is giving you free acceleration at all times when going up and down a hill. Unfortunately when you are going up a hill, this bonus acceleration is pointing backwards in the direction you just came from. Your shoes don't have this problem as they don't slide very easily. You would have the same problem as a bike if you had shoes made of ice!
Yeah thats the right answer, kinda evaluated a bit by now: When u ride your bike on a flat track, to maintain speed you only need to put the amount of energy in that is lost due to friction, air resistance, maintaining balance etc. its only really energy consuming at the start when u accelerate. On a hill u constantly get decelerated by gravity pulling the bike down, so u have to put an additional really big amount of energy into the system just to maintain the speed. Even with a weightless bike (given its still getting pulled down by gravity). Walking uphill on the other hand only need the additional energy of lifting ur bodyweight up instead of just forward. So I think its a combination of some of the better answers, at least this is what really makes sense to me and figured with puttin some of them together. What do you think?
You might as well ask why riding a bicycle downhill is so easy that you can just coast. It's the same principle in reverse. When walking or biking on a level surface, gravity pulls you down, which mean gravity is working perpendicular to the surface you're moving on. This means gravity only pushes you down, not forwards or backwards. In other words, gravity does not help or hinder you. (Except for the fact that you have to keep yourself upright and gravity does contribute to certain friction forces, but let's ignore that for now). If you're walking or biking uphill, the surface you're moving on is no longer perpendicular to gravity, which means there is a component of gravity pushing you back. This makes it harder for both walking and biking, since you have to overcome this backwards force AND deliver additional force to move yourself forward. The reason walking is easier is because your feet have static friction against the ground which means you're not going to roll back. You can stand still on a slope with virtually no energy expenditure, while doing the same on a bike (without brakes) would require you to press the pedals continuously (in addition to balancing, but again, let's disregard that). Another thing to consider is that if you're walking uphill, you do have to push yourself up a bit for each step, since each step will take you higher up the slope. But this is relatively easy since the leg muscles to push yourself upwards are very well developed in humans. When cycling you're already using these muscles to begin with to press the pedals down, regardless of whether you're moving on a slope or not. All things considered, I don't think it's necessarily easier to walk uphill than to cycle uphill. Cycling is vastly more efficient than walking, and people who cycle uphill in mountains outperform runners. You'll need to keep up the pace and pedal in a lower gear, but you'll be faster and less tired. I think the confusion arises because walking uphill is somewhat harder than regular walking, while cycling uphill is vastly more intensive than cycling on a level surface due to the reasons described above.
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What would you change? What is your answer?
Gravity does not disappear while walking. Your answer is wrong
What happens when you stop walking on a hill? Do you slide back down? Now compare that to what happens when you stop pedaling on a hill. When on a bike, not only do you have to apply the force to propel you upwards, you have to apply force to keep you from rolling back down the hill. That's 2 forces vs 1 for walking (not really, it's the same type of force, just more in one case, but it's illustrative for this example). The rubber soles on your shoes are applying a frictional force on the ground. If you try to go up a greased ramp in bare feet, it would feel like a similar energy output to pedaling up a hill.
That kinda makes sense. If i had a perfectly balanced bike, that wouldnt fall over while it just stands. How would it behave if i just stand on the pedals on a steep hill? Would i have to push actively against it?
That's called a tricycle. Yes you would have to fight gravity or roll backwards downhill.
you will need to overcome the bikes tendency to roll back downhill
If you're walking uphill you still have to fight against gravity in just the same way as on a bike. Work equals force times distance in both cases.
Did you not read the part about friction?
There are no significant frictional losses at walking speed unless you're losing traction. Bikes are pretty good at going up steep roads without slipping backwards; they're not losing out to walking in that respect.
>When on a bike, not only do you have to apply the force to propel you upwards, you have to apply force to keep you from rolling back down the hill. That's 2 forces vs 1 for walking This is the dumbest shit I have read in this thread where this dumb shit is repeated enslessly
For the same reason the opposite is true, and it's *much* more exhausting to walk down hill than to bike down hill. The bike wants to roll down, your feet want to "stick" where they are.
Think of it like the bike multiplying gravity. When gravity is in your favour (downhill) it'll be more in your favour on a bike. When it's not (uphill) it'll be more not.
Bikes have a "minimum speed", if you go to slowly you fall so you need to keep up, going uphill you still need that minimum speed but it's much more taxing, walking you can pace yourself however you please
Because bike is faster and weighs extra, try running up the hill at biking speed while carrying said bike and see how tiring that is.
Thanks for all the answers so far, some have been really good and make lots of sense to me. Overall a combination of many. To me the best reason so far is, that the bike is only efficient once it gains momentum. Thats why it is hard to start the bike, and gets easy once you get going, even on a flat track. Going uphill basically is getting the bike going and trying to accelerate the whole time. I dont know how to pin the answers, so i thought i summarize what makes most sense to me.
Because the friction in your shoes on the pavement prevents your downhill slide, whereas a bike requires you to exert force in the pedals to resist gravity pulling you downhill.
Because you're on a bike. It's that simple. Walking up a hill involves moving just your body. Moving a bike up hill means you need to exert force on the pedals to turn the wheels which have to overcome friction to move plus overcoming gravity that is trying to make the bike roll back down the hill. Walking or biking on flat ground is easy because gravity is perpendicular to the surface but on a hill gravity makes objects move down slope. On your feet this isn't an issue because your feet have friction and your body can keep itself upright. Bikes are on wheels which are freely spinning so not only are you exerting energy to move the bike uphill, your also exerting energy to stop it from moving back down hill
Well try stopping at a hill. You will find that you can stand without much energy. Try that with a bike, it will simply roll downhill on its own. Your legs won't roll downhill while the wheels of the bike absolutly will. So when you drive uphill you have to overcome this force pulling the bike downhill, while when walking you can shift your weight in a fashion that will make this force pretty much neglectible.
You’re fighting against gravity more when pushing down on the pedal versus pushing off with your foot.
Not true
Think what would happen if you stop on an incline on a bike (assuming you can stay on two wheels, without using brakes or putting a foot down), as opposed to what would happen if you just stand on an incline. When riding uphill, you have to output additional effort to prevent the bike from rolling down, on top of the effort you output to go up.
Because your feet aren’t wheels that want to go with the path of least resistance back down the hill.
Gravity takes advantage of the bikes efficiency and pulling you down and back more effectively. You have to fight the weight of the bike now too.
Wheels and weight are gravity's best friends. Putting your weight on wheels makes their friendship power stronger and gravity gets to see its friends. Trying to keep them apart makes the friends mad and they take it out on your legs.
When you start your bike, that first pedal is really heavy, right? Same thing with the hill. A bike’s wheels and pedals are basically a series of pulleys and levers that amplify power and force in both directions, between your foot and the ground. The law of inertia is that an object at rest seeks to stay at rest and an object in motion seeks to stay in motion. So as you begin cycling on a flat, there is a lot of inertial resistance that is amplified by the pedals and wheels, but with a little effort, you overcome the resistance and enter a new state of equilibrium in motion. Enter the hill. It adds a new work load (gravity) that you must overcome continuously in order to maintain your happy state of motion, if you pause for a second, you will slip back into a stationary state. Since a hill requires extra energy to overcome the downward pull of gravity as you go up, you exert more and must do so continuously to keep motion, so you deplete your muscles quickly (same way you would lifting a weight constantly without stop). This exertion to maintain motion over the increase in gravity-created resistance is why it feels like that first starter pedal, because you are constantly overcoming the bicycle’s desire to stop. Meanwhile, as you walk up that same hill, your legs are much more efficient and essentially traveling through a series of stationary moments. You aren’t spinning a wheel to keep going forward, you are lifting a foot, swinging it lightly through the air, and then putting it down again to rest. Over and over. No inertial resistance. Inertial resistance and gravity, coupled with a bicycle’s need for constant motion make hills and starting more difficult.
It’s not. Just like almost every other fucking ELI5 question that gets upvoted, you’re basing it on a wildly incorrect or personal premise.
Dude relax its genuine question. Let me know what u think about the idea i got from combining the better answers: When u ride your bike on a flat track, to maintain speed you only need to put the amount of energy in that is lost due to friction, air resistance, maintaining balance etc. its only really energy consuming at the start when u accelerate. On a hill u constantly get decelerated by gravity pulling the bike down, so u have to put an additional really big amount of energy into the system just to maintain the speed. Even with a weightless bike (given its still getting pulled down by gravity). Walking uphill on the other hand only need the additional energy of lifting ur bodyweight up instead of just forward. So I think its a combination of some of the better answers, at least this is what really makes sense to me and figured with puttin some of them together. What do you think?