Why does pedaling up hill feels harder than walking up the same hill?



Why does pedaling up hill feels harder than walking up the same hill?

In: Physics

Because you are on wheels and gravity is trying to force you down the hill. Where as when you are just walking up it you can keep yourself steady. Not sure if that explains it well enough but yeah.

When you walk you control your momentum, you lift your feet and step forward, however when your biking up a hill you are now pushing a peddle that’s pulls a chain to spin a wheel that requires more force to move due to the resistance, weight of the bike, what gear you are in (always go as low as you can for hills before you start going up)

That’s because you are moving against the gravity. And a component of gravitational force is pulling you downward while you are moving upward.

It wouldn’t necessarily be the case if you were taking advantage of gearing on your bike. That said, assuming you have a fixed gear and can’t switch to a lower gear for the incline waking seems easier than pedaling because walking is a very efficient and natural motion to begin with. Half the motion is a controlled fall so gravity is doing some of the work and it’s very easy to modulate your effort to make things easier or harder as you see fit.

Pedaling isn’t as natural a motion for your body so it’s inherently going to feel more difficult. In addition you have to deal with the extra weight of the bike as well. In simplest terms riding up a hill is just more work. More weight to carry.

It’s mostly because bike gears, even first gears, are usually designed for greater speeds rather than power. It means that it transfers the energy of the pedaling into a higher rotation speed for the wheels at the cost of torque. When you are going uphill, the speed is quickly lost due to the acceleration of gravity, so a part of the work you do by pedalling is lost.

One obvious cause is that you have to push the bike. Extra weight is quite important when going uphill, so adding 5-20kg of bike is not trivial.

Another reason is the “shape” of the effort.

For example, when going flat on a bike, you can push very hard when the pedal is around horizontal, and not push as hard the rest of the time. That’s fine, because the bike does not slow down much between strokes.

When going uphill, the bike will slow down a lot whenever you stop pushing on the pedals. You almost have to push continuously.

Human muscles like working like the first case, making pulse like efforts. And don’t like making continuous efforts like in the second case. So, on a bike it’s more difficult to output the same power going uphill Vs going flat.

I suppose the same is observed for walking uphill Vs riding uphill: your muscles are ok with the shorter bursts that make you walk, but find it harder to spread out the effort when on a bike.

There are more steps to cycling a bike than walking. Your feet press against pedals which convert this force through chains and gears to movement in the wheel, which inherently pushes you forward. If you change the configuration of the useable gears on the bike, you can make the uphill movement much easier at the expense of more effort (more revolutions of the pedals), you also have an element of balancing not inherited in your predecessors evolution – not like the automatic balancing you’ll find when standing up straight. In comparison, you walking a hill is placing one foot in front of the other and pushing yourself forward – less steps to produce the same gain forward / uphill. Lastly, you may be prejudices against cycling that cloud your ability to realise the true exerted effort between motions, perhaps a hatred of bike rides from younger years…

When you go up the hill the energy you need to increase in altitude depends on the mass and elevation.

Riding a bike on flat ground is easier because the friction is low but when you go up a hill that does not help, the problem is that you move up so against gravity.

So lifting you up is the same work walking as riding a bike. Let assume you walk and push the bike up the hill beside you so it mass is not relevant.

You tend to move at a higher speed with a bike so you have to do a bit more work at a short time so the power output is higher, how hard the sake feels to you depends on the power output.

If you ride a bit at walking speed or a road with less include but a longer path so the time the top is the same as walking then the power.

For bikes, there is another factor, the cadence that is the number of revolutions per unit of time you move the pedals. You like to be at 60-80 rpm.

Power = cadence* force so if the cadence is lower you need to press down your feet harder. This is often the problem why riding up a hill. The gearing os so that the pedals move very slowly at a low speed and as a result, your legs cant press down the peddle hard enough.

If the gearing is so that the cadence is too high most of the energy is spent moving the left not pressing down the pedals.

So if you have a bike that has gears so you can have a cadence of 60-80 RPM the power you need to go up the hill is the same as if you walk and push the bike. So for example a mountain bike can be used to go up the hill with the same work as if you walk.

At low speed on a bike the balance will be a problem and that can be a limit you too,

You’re comparing apples to oranges. The first one is you trying to lift you **and a bike** up a hill and the second is just lifting you. Strap the bike to your back and you’ll find walking up the hill far more tiring.

That’s assuming you’re in the right gear for climbing hills. The gears on your bike are a way to trade effort for distance. In higher gears, you get more bike travel for pedal travel, but you need to supply all the energy that travel will take. In a low gear, your ratio is about 1.2 to 1.5 to one. That means one downstroke of the pedals from top to bottom (half way around on the pedal) gives you 2/3 to 3/4 of a rotation of the wheel and about 1.5 meter/yard of travel. This is why low gear feels “floaty”. It far easier to move a bike that distance than to take a step, so your legs have a lot of spare strength that isn’t being used.

When you shift to the highest gear, you’re at about 4.5-5 to one. That’s great on flat ground where that one step on the pedal will move you 5.5-7.5 m/yd. At a fairly slow pace of one downstroke per second that works out to about 15mph/23kph. That’s about twice as fast as jogging for much less effort.

Going up a hill in high gear though means that one downstroke needs to supply all the energy to raise the bike over that greater distance. You’d struggle to jump that high with the bike on your back, and so you struggle on the pedals too.

Because gravity makes your bike (that is also carrying your entire body weight) want to roll back down the hill. The wheels make it so that it’s easier to move with the same force, and on even ground, that’s a good thing – the same amount of effort will take you way farther when pedaling than walking. But that also means the force of gravity is way more efficient at pulling it back. Walking up a hill means pulling yourself up step by step, but you don’t have that force acting on you in the same way.

Gearing helps a lot, but I’ve wondered this too.

Intuitively/anecdotally, I find that my line for when walking is easier is when pedaling becomes more anaerobic (think big pushes or “sprints” on the bike) in order to keep the bike balanced.

Aerobic exercise can be done longer, so for a hill it’s preferable to stay in that state as much as possible.

When you’re walking up a hill you are carrying only yourself. When you’re bicycling up a hill you are carrying both yourself and the bike.

The additional weight of the bike coupled with the fact that gravity is constantly trying to pull the bike down the hill means more effort is required to get up the hill.

Stand on a hill and place a wheel on a hill. You will notice that your feet stay in place, but the wheel will naturally roll down the hill without any additional force.

A bike wheel is designed to be as easy as possible to gain momentum, but that goes both ways. When you are riding a bike uphill, in addition to applying forward momentum, you also have to counter the natural backward momentum of the hill. You will run into the same problem with sleds or skis.

basically a bike and the way a bike works is adding more steps to your goal(which is to get up the hill) and so it requires more energy. That and the muscle groups required for you to go up a hill on a bike are different from the muscle groups required to go up a hill while walking. Also friction, on wheels, there is less friction preventing you from rolling down hill backwards, on foot your feet provide the necessary friction to prevent you from sliding backwards.

The thing nobody is mentioning is power

You walk slower than you pedal.

Even if the bike was weightless, pedaling makes you go faster than waking. And that translates in more power being delivered. That feels hard

With the proper gears, you could pedal at waking velocity and it should be as hard as waking.

Other than that, there is a matter of geometry of the pedaling vs walking. Different muscle groups and such.

Mostly because you aren’t used to cycling. I can ride for an hour uphill in the mountains at twice the speed I can walk at about the same effort level. I’m 60 lbs overweight but I’ve been cycling for 30 years.