Have you ever done the "Ghost Bike" experiment before? What happened?

As a long time bike person I can also comment on that the amazing thing about a bike is that when you make a turn, you actually first slightly turn the handlebars in the opposite direction of your turn (so called "counter steering"). Many bike riders deny this because it is so counter-intuitive, but it is actually for real.

Studying advanced motorcycle handling teaches a combination of how center mass, speed, and friction points interact to keep a bike on track and in control for given conditions. There are all kinds of forces at work, then you add in what changes with applying the brakes or throttle at any given lean angle plus speed. All of this is acting on a contact point between the tire and the road about the size of a credit card. It is really a great exercise in physics and engineering once you realize how complex a system it really is.

how can they stand up?.. bikes are are Two Tired..

I believe the angle of the forks on the bicycle also factor into the 'Ghost Bike' ability to self steer. Kinda like the toe and caster on the steering on a motor vehicle to self straighten the steering wheel (when properly set up). Great topic, thanks for sharing.

The tendency of a bike to balance itself is partly due to the rake of the front wheel that is, the angle at which the fork holds the wheel. I experimented with my bike by turning the front wheel completely around thereby placing the centre of the wheel directly under the handlebars. This made it practically impossible to ride. Try it!

Its less about center of mass and more due to a few aspects of bike geometry, specifically head tube angle and the mechanical trail measurement. These can vary greatly between bikes but they have the most to do with a bike’s tendency to right itself.

Came as soon as I got the notification popped up and just as a convenience i was just thinking about this very topic. Amazing work startalk team keep up the good work.

Neil on your example of the bike with the wheels that spin backwards it doesn't cancel out the gyroscope factor. Because that video with the wheel spinning and you can levitate it from one side. That wheel doesn't care which direction it spins the angular momentum still holds it upright. So the bike no matter which direction the wheels spin it would still hold it up. You were onto something with the front wheel turning into the lean though. Because fyi if you try to do that with the bike backwards down a hill it won't work the bike will tweet and fall over every time. The reason the bike steers into the turn going forward is the caster angle of the front forks. That's the reason a car wants to go straight if it's aligned right. But in reverse if you don't touch the wheel the wheel will try to turn full lock one way or the other. It's the caster angle. If that bike goes backwards down the hill the caster is backwards and it will fall. If the forks were perfectly vertical the bike would not be as stable. If the forks went the other way it would want to crash all the time. The caster is what keeps the bike going down the hill.

Fun Fact: What a lot of people do not know is that high wire bicycles are what we bicycle people call a “fixie”. They have the rear wheel mounted in reverse so the caliper and or disc brakes can be removed and the way you break is by back pedaling. Which is why they are able to go forward and backwards. Fixies are bikes that not only have a single gear, but that single gear is fixed at all times. So no matter if you go forward or backwards, up hill or down hill you are constantly pedaling and your speed is determined by how fast your legs can move. You can control your speed by controlling your cadence. There is no coasting. Also a ‘secret weapon’ that fixies have is bringing your feet up off the pedals and resting them on the handlebars so the pedals can freely spin when going down hill. They pick up incredible amounts of speed this way but the only way they have to break is to put their feet down, back pedal or skid the rear tire left and right. Fixies rarely get stolen because you can tell they have no brakes. My ultimate goal on a bicycle is to be skilled with my own fixie one day.

Lots of really good comments on this one! I want to try to clarify the correct answer to the original question as best as possible. "HOW" does a bike self-balance? Well, "Trail" is the distance from the tire's contact point with the ground to an invisible line through the front wheel's steering axis where it intersects the ground. Tilted steering axis or not, if the tire's contact with Earth is behind the steering axis, you have trail. If the bike is pointing straight ahead, and both tires are directly along the bike's centerline beneath the center of mass (COM), then there is no effect on steering from the mass of the bike or how it relates to the COM of the bike/rider system. But if the bike leans, the contact point of the tire is no longer directly under the COM, and TRAIL becomes a lever arm that turns the bike's steering in the direction of the lean. Here's how you can visualize that. Let's go the the extreme: If you lay a bike horizontally on its side and push up on the front tire where it would make contact with Earth, it easily turns the steering towards the ground, towards the side you laid it down on. Another thing you can do with your bicycle (or motorbike if you're really strong). Hold it upright, not moving, steering straight ahead. Then without touching the handlebars at all, lean it to one side. Because of friction it may not steer right away, but pretty soon, that steering will turn toward the direction of the lean, and that's because of the lever arm of this magic thing called "trail." And you're not even going anywhere! So if you're riding, at most realistic lean angles the force from that invisible lever arm causes the wheel to turn toward the direction of lean which moves the tire contact points back underneath the COM hence balancing the bike. But COM does matter. A high center of mass will require different steering geometry (angles) to automatically balance the bike, and as some here have said, you may want more or less balancing depending on what the purpose of the bike is. Fast and nimble - maybe less trail (a shorter lever arm), or more for comfort and easy riding - go for more trail. Finally, if you have an old bike where you can spin the steering around backward, this gives you negative trail, and all the balancing effects are reversed and good luck giving that a go!

Derek has an amazing video on this topic on his channel Veretasium. It explains the balancing of bicycles so well.

When I was a young man, I had a go on a 'high wire' training bicycle. It didn't have the big floppy pole (pfffft!) but it had a framework attached to the rear wheel hub that hung 4 ft below the wire at an angle which put it directly below the saddle. There was a 28lb weight in it and that made it almost impossible to fall off! A perfect example of stability through the lowering of the centre of mass. (The wire itself was a nosebleed -inducing SIX FEET off of the ground!)😅 💚🐇🐴💚

I saw Veritasim's video on the same topic couple of months ago. He experimented riding bicycle with locked steering wheel and it was impossible to balance. Nice to see further explanation and example of highwire.

Neil, I'm with you on most things but you're wrong on much of this. You're right that gyroscopic force isn't a big factor but a motorcycle can still be ridden if it's 10 feet tall with the center of mass several feet above the ground. You're right that the front wheel wants to turn as the bike leans and that has to do with the geometry of the front forks, "trail" specifically.

Neil didn't quite hit the nail on its head here in my opinion. - Trail (contact patch behind axis of rotation of the wheel) is the mechanism that auto-centers the wheel at speed, though it doesn't have any effect at a standstill. Think of caster wheels on a shopping cart. - Rake (inclination of the head stock) inevitably produces trail on a bike with straight forks but it also creates another effect: if you lean the bike a bit and then rotate the wheel slowly, the whole bike will shift side to side slightly but also there will be an angle where the bike sits the lowest on the ground. Now whenever you leave that angle, it raises the bike up very slightly. If we eliminate friction, gravity will always keep the wheel angled in that special angle, which seems to be the correct steering angle for a given lean of the bike, yet I wouldn't be too sure about that. This effect is similar to Neil's balancing stick example, but it's probably only relevant at a standstill, when friction of the tire on the ground is minimal. - Gyroscopic effect is an apparent force that pushes the bike up when it's in motion and leaning to one side. But it can't be the only relevant effect here, because then the bike would just come to rest at a certain lean angle but roll straight on. - When the bike leans, the contact patch shifts to the inside of the curve. This might put leverage on the front wheel to steer it into the turn. The rolling circumference also gets smaller as the bike leans, prompting the wheel to accelerate its rotation, but because of inertia the wheel will instead react by putting leverage on the steering axis, steering the wheel into the turn. If this effect is significant or not, I don't know. I'd be curious to see a computer simulation which can eliminate various factors to see which ones truly contribute to the self-stabilizing of a bike.

In other words bikes have a very cool mechanical auto-steering feedback system for maintaining balance. They self correct their balance with clever mass distribution and head tube angulation.

Still funny seeing Gary O’Reilly with these two, that semi and final were terrific in '90, good times.

Another fun counterintuitive thing about bikes: the weight of the rider is not actually supported by the bottom of the wheels; instead the rider is dangling from the top of the wheels. The spokes are very thin and have very little strength under compression, but they have great strength under tension.

Not often is Neil off the answer, but he completely is this time. Of course wobbling brings the center of mass CLOSER to the ground, which is opposite to what Neil is saying. The reason the system is stable is that the caster angle makes the steering wheel a self-balancing system that compensates instability with a turn to the proper direction due to the gravity pull.

The balance pole seems to be more of an inertia thing, if you start leaning to the left, you push the left down which will push you up, you can tightrope walk with no pole by swinging your arms above your head, much like in Tom Scotts tightrope challenge A centre of gravity demo would be the balancing toys where a weight is physically below the balance point

An interesting fact about motorcycles is that a bike set up for Trials, which involves a lot of low speed maneuvering, has a steeper rake then a bike set up for road racing which has a gentler rake angle. Motorcycles set up for drag racing which aren't intended to turn, have their front wheel extended out a few feet to keep them going straight. To get a motorcycle to turn left you actually press down on the left handlebar and to turn right you press down on the right handlebar. Having a single disk brake on the front wheel doesn't make the motorcycle veer to what ever side of the wheel it's mounted on. And you don't lean on a motorcycle in curves, you keep your body straight to maintain stability! Understanding the physics of a motorcycle is important!

There is no doubt, Neil Degrasse Tyson is my favorite explainer.

Thank you, Mr. Tyson for the explanation. As a motorbike messenger for 6 years straight, I've always thought about the Center of Mass and Gravity's effect on my motorbike. And I've taken a pro riding course that involves lowering the CMG during cornering too few years ago, which makes me believe on it even more. Thank you, Sir. Once again.

Yeah it's called counter streeting, that's how all bikes are steered by riders. Much more obvious on a motorbike at speed. So you initiate a fall to the side in the direction you want to steer in then you steer the opposite direction so that the front tyre tracts the desired radius.

A UC Berkeley professor hosted a "Bicycling Science" lecture at open house. He had a bicycle made with geometry that caused it to steer left when leaning right, and steer right when leaning left. (But not a reverse-steering bike via the handlebars like "Smarter Every Day.") He let me ride it and was impressed that I had no problem first try. But it was horrible how you had to fight the natural geometry to get it to "steer into the fall."

We gotta "know" the 'critical' center of mass in the system we desire - like on our bikes or up on the wire. 'Critical mass' like the moment between not boiling and boiling - there's a point of no return - the center of mass can bring you down to the ground because it is so heavy- it ain't easy till it's easy, then it balances. You don't forget how to ride a bike, so they say. As an off-road rider I grok this, the bike will just stay up if you keep yourself flexible, strong and ready to go with the bike. Use the throttle and clutch to keep momentum and brakes to control speed. You put the body's momentum toward the line you want while looking fairly far ahead. Hitting huge rocks will fling you one way or the other and the bike will just stay up if you can hang on and stay ahead maintaining correction momentum for the body to match the center of mass toward the lowest point in the system. It's an amazing fun ride.. hang on!

Balancing a bike without a rider has everything to do with the caster of the fork, not the center of mass.

Neil, would love to hear about the physics of a motorcycle jump. Especially what looks like rotational control in mid air. Is the rider, for example, applying the brakes a bit to rotate the nose downwards?

Really great and fun explainer 😁 I remember Veritasium doing a long deep dive video into this subject.

I am no physicist but I think that for a bike (or any comparable vehicle) to stay upright, the center of mass must actually be ABOVE the center of the wheels. And if you think it through that kind of makes sense: A system of any kind is only stable if it is able to counteract any disturbances from its equilibrium (like those wiggle-dolls you mentioned). For a bike that means that if it is going in a straight line and upright, it must counteract any motion that drives it away from that configuration. Imagine the bike (going at some speed) tilting slightly to the right (or left). What happens initially is that the front wheel will - due to its gyroscopic precession - turn inwards to the right, ultimately forcing the bike to turn. Now, because for most bikes the center of mass is located pretty high up relative to the center of wheels (plus rider even more so) that turn will induce, loosely speaking, a centripetal force on that center of mass to the opposite side, resulting in the bike leaning back to the left. This will go back and forth until the front wheel is aligned again. If that doesn’t appears convincing, picture a bike where the upper half of the frame is made of light plastic and the lower half is made of heavy lead. If that bike, rider excluded, were to go downhill starting in a stable configuration and started to tilt to the right, I would not expect the bike to realign itself. But that’s just my theory and I could be totally wrong haha. Cool video anyway✌️

Regarding Gary's mention of "food delivey drivers", In urban UK cities, those services are very often bicyclists, not motorists in automobiles.

Interesting... I was convinced by the gyroscopic effect explanation - because this is what I learned while training for my motorcycle license... But if that is not the proper explanation, then there is something else my instructor said that does not make sense anymore: he told me that past a certain speed (around 30 km/h so about 18mph) the gyroscopic effect makes it so the bike simply cannot fall - unless you lose traction or hit something of course. And it does indeed require a conscious effort from the pilot to keep the bike up at low speed - some bikes require more effort than others, due to their center of mass of course... So here's my question (to which I'd bet you have the answer). If the gyroscopic effect is not responsible for this... Why does the bike have to reach a certain speed to be automatically stabilized? Thanks for everything you teach us through your videos btw!

Having your center of mass on a 2-wheeler low is not actually helping with stability, it might be doing the opposite. I have riden very low lowracer recumbents with center of mass of the rider just about 40cm above ground and tall 29" upright bikes with their center of mass maybe 110cm above ground. The low bike requires faster reactions to anything that destabilizes you. It like balancing a short stick on the palm of your hand versus a long stick. Other things being equal lower bike will require faster reflexes and therefore feel less stable. But you need a big heigth difference to notice this. Among just upright bikes for example other differences will be so much more noticable they will hide this one. To make the bike balance without rider you need the steering assembly (front wheel, fork, stem, handlebars) to lean to the side the bike wants to fall to faster then the rest of the bike. Then any disturbance of the initial upright position will result in a turn that corrects it back to upright. It does not matter if your design uses the gyroscopic effect to help this or not, or how much exactly the front wheel trails behind the steering axis. As long as the steering falls into a turn fast enough (but not crazy fast, that could induce fast oscilations) it will work and you can send that bike down the hill and see it keep going. However once you put a human on it it becomes more complicated. The weight of the arms on the handlebars by itself already changes the behaviour of the bike. The overall mass is now much greater and center of mass is in different place. And the mass is no longer rigid, most of it is somewhat flexible and actively moves too. And the person steers actively to keep balance but with the limitations of human reaction times. So now describing the stability of this bike-human system becomes crazy complicated. To my knowledge nobody ever built a good mathematical model for this that would let you predict what bike geometry would be nice to ride. The only way is to build the bike and test it. As a result I have seen bicycles that were not only not stable to ride themselves down a hill but you could not even push the bike just by the saddle, you had to have a hand on the handlebars when pushing it. And yet it was perfectly nice bike once you sit on it and ride it. Just the change in mass and its distribution did the trick. And I have seen a bike that is nicely stable when you push it by saddle alone and yet it is unpleasant to ride - steering feels rubbery and like it is fighting you.

I remember when I was a kid, I did this experiment (I heard or read about it somewhere, but I don't remember where) where you put a fork and spoon together with a toothpick pushed between them, balanced on the edge of a glass, then you light the inward-facing end of the toothpick on fire. It burns to the edge of the glass and stops, and you're left with this thing standing on the edge of a glass, barely touching it, yet staying put. Pretty simple physics, since it's just keeping the center of gravity so low, it can't tip in either direction, but it looks completely counterintuitive.

I have a different explanation: centrifugal force. Every time a rolling wheel begins to fall over, it's path to motion curves to the direction of the fall. At that moment, centrifugal force kicks in and puts the wheel back upright. Watch a rolling coin carefully and you will notice that it wiggles as it slows down before losing balance and falling over. As it slows down, the centrifugal force weakens hence the wriggling. Eventually got, the centrifugal force is to weak to counter the fall and the coin falls. It's the same effect with a bike.

I still got the scars of me standing up on a bike. 😂😂😂

Hello Neil, my name is Benjamin and I will definitely be more of your patrons someday, my biggest mind boggling question is. Out of all the plants we observe, stars and galaxies, and now having a James Webb telescope that could either see into the past or now how come, we have not found now another planet containing green life like we do where does trees really come from?

A balance pole need not be "floppy" or hang down to be effective. What the pole does is give the arealist a source of torque. Example: From the arealist's viewpoint, if they should lean to the left they can impart a quick counterclockwise torque on the balace pole. The counteracting torque enables them to shift the center of gravity to the right, to a point directly over the wire. Of course, you could have a pole whose ends were below the wire and were heavy enough to make balancing automatic, but you won't see that in a circus act. The length of the pole also increases the polar moment inertia, making the arealist less likely to rotate off center.

Wait, how'd I miss THIS????? Thanks!!!

This is the first time I have seen Tyson get something wrong. For a Motorbike it is all about Castor not Centre of Mass. The contact point on the ground is dragging behind the pivot point of the wheel. This is why it only works when moving, Tyson’s description would also work when standing still. Other than that his description of it turning into the lean was correct.

4:58 I was thinking that this is how i definitely do it, though it’s a conscious effort for me

Ye not sure I agree, but when I was a kid I tried to do the ghost bike trick with the handlebars removed and it didnt work so in my opinion it has to do with the handle bars on the bike which makes it stable.

Question: In which direction do you turn the handlebar on your bike if you want to go right? Clockwise or counterclockwise?

On my Dad's desk was a metal highwire figurine that stood on a metal cylinder. I would watch that thing teetering back and forth and be amazed by it. He explained it but it didn't really get it when i was 4 lmao. (Back and forth though, not side to side.. but same principle)

you also when at speed you don't turn the bars in the direction you want to turn, you push forward with the hand in the direction you want to turn and physics takes over.

Me and my friends used to do that all the time!!! 1:45 😂 Nice 👏

Here's my counter question: If the pole is for lowering the center of mass, the highwire walkers who do this without a pole usually use their outstretched arms to balance...If lowering the center of mass is the way to go, why lift your arms up to shoulder height, instead just keep them low by your waist?

When I sold bicycles, someone came in and paid cash ($600 on 1973) for a Lejune Pro. I had it put together and rode it before the customer picked it up. All you had to do to turn that bike (a really good one at that time) was to lean one direction or another.

Neil can you do a follow up about motorcycles and the notorious death wobble and how to correct for it?

Centre of mass below the axles. Spinning wheels have gyroscopic force, but the steering geometry needs to be such that the front wheel returns to centre.

Neil, thank you for the excellent explanation of the equilibrium on the rope. But when I was a kid, we used to walk on the rope with a rigid bamboo pole and not the flexible one. Of course the rope on which we walked was not very high and the pole was only about 3 m in length.

It would help if you explain it in simpler terms, the key here is the forks being at a specific angle that they turn in the direction the bike is leaning so once the bike is in motion and it starts the lean the front wheel turns into the lean creating a braking force slowing the bike down however, the rest of the bikes weight overcomes this braking force by pushing on the front wheel because it does not want to change direction forcing the bike to stand up because is pushing against the lean... ask any motorcycle racer what happens if you are at a lean and you brake using the front or accelerate, the result is the same the bike stands up because you load the front and because the rest of the bike is heavier than the front wheel forcing the front wheel to alight with the direction of the biggest mass moving forward however if you apply read brake the bike leans more.

The best film version of ghost bike is found in ‘Jour de Fete’ by Jacques Tati. It parks neatly at a cafe in jaunty manner. Two counter-rotating wheels sharing same axle and plane of rotation cancel out? I know very little. A single rotating wheel is more stable than two with one joined to frame and one freely yawing…….

Very interesting

Dr Tyson, you have to do a video on pumping groundwater and it causing 31inches of tilt to the earths axis, its really interesting!! Need to hear you teach me more about it please!!

Bicycles are rear wheel drive so the gyroscopic precession is in the front wheel. The industry term is "e-bike". Which is short for, electric bicycle. The battery pack on e-bikes is typically on the down tube or seat tube. #Bicycle #GCN #Bike

That information was fascinating to me. One reason is that women's center of mass is located in their hips. Men's is located in their chest. So if you're a male wire walker, you DEFINITELY need that curved pole to stabilize your connection on that wire. What do you think? I mean if I were a female wire walker I'd still carry that curved pole, but it's interesting to me.

Question that popped into my head is if cats change the center of their mass when they fall? As they "always" land on all four. I have read that by pulling the paws in towards the body, the cat causes the front part of the body to rotate faster than the back part. When all four paws are facing the right way, they can absorb the shock of impact. Whats the science behind it?

For the COM to provide absolute stability of a bike, the COM would have to be BELOW the ground level. Think of an inverted V resting on a horizontal rod: completely stable. This is never the case with any bike, no matter how low its COM is. The fact that the bike can stay upright only when rolling strongly suggests the stability is coming from the gyroscopic action of the wheels.

Cool. Next, do one about how cars stand up.

It's the curve in the front forks that makes the bike go straight. if you analyze the geometry you can see that when the handle bars are turned that lifts the front of the bike slightly. therefore, in order to turn you have to put energy into the system. i.e. the bike goes straight unless some force acts on it.

Great one

If a counter-rotating wheel on a bicycle cancels gyroscopic action, does the mass of each counter-rotating wheel need to be equal? Also, ust a thought.If the high-wire walker's pole dips on one side, it would tend to raise the other side a nearly equal amount, and the center of mass would not necessaily be lower to the center of the Earth. The walker (himself/herself) is in effect a movable fulcrum in relation to the pole.

Apart from gyroscopic forces there is also another self righting force generated by the castor of the front wheels; i.e the angle the handle bars make when connected to front wheel. That's why you can let go of the handle bars in motion and the bike won't tip over and continue to follow a straight line. Perhaps that explains why the bike with the counter rotating wheels to cancel gyroscopic forces was still able to stay upright.

Why would anyone think it is gyroscopic effect? For gyroscopic effect to stabilize a rotating mass on it axis, it has to revolve or precess on the third perpendicular axis, that means the bicycle has to go on a curve and make a circle on downhill, but it doesnt, it go downhill straight. BTW, it is not just bicycle, it happens to a wheel, single tire rolling down the hill as well. When a wheel is rolling downhill, there must a force which should act on axis of rotation to brought it down. But during downhill roll, the CG shifts towards front of the tire, so it rolls faster and still no sideway acting force. If anyone who thought it was gyroscopic effect before does not understand gyroscopic effect.

In “The Whole Earth Catalog” there is a listing called “Intelligent Motorcycling” and the review said, A Contradiction in Terms”.

I have developed balance issues when I walk, so I gave up riding my bike. But after a year, I thought to try it again. Much to my surprise, I discovered my balance is much better on my bike then walking. It actually feels normal. What puzzles me now is that when I was a kid I used to have no trouble riding with no hands. And yet I cannot do that today, or even before my balance was an issue.

Hey, we actually do that instinctively. Tried to walk over an edge? What's the first thing you do if you're leaning sideways? Spread your arms wide open, just like that pole. And it is not calculated.

I just got one of those newfangled e-bikes. And all this talk about angular momentum makes me want to go for a rip. I have a headlight and taillight now too 🤓

A bike with a higher centre of gravity isn't necessarily less stabile in the same way reversing a long trailer is easier than a short one. The pendulum is longer.

Is there any way an unsteady walker could use any of the principles to make it harder to fall? Or does a walker do that, even though the idea seems simpler? I'm not there yet, but I wanted to know if there's any way to improve walking around for those who have trouble.

Thank you! Neil!

I actually have a electric mountain bike with fat tires for stability outdoors, I can 100% say you can ride it for awhile without hands because with pedal assist it’s enough momentum to stay up and depending on the road and how it curves the bike will stay on course. 90° angles are the tricky part.

I saw some guys at the park walking on a high wire that was just a few feet off the ground tied between two trees and I just knew I would regret it if I didn't ask them if I could try, so I did. Its hard! Its really hard without a pole. They didn't have one and I only went about 3' before I tumbled off. Glad I tried it though, cross that one off.

Just thinking about walking a high wire... 100% I’m seeing this through the lens of me doing it. Which is why I it’s thrilling. Because I have a fear of heights. Knowing that physics is applying forces in invisible ways mitigates my fear.

When it comes to bikes and motorcycles it all comes down to the rake (offset angle) of the front axle and the fact that the fork can move turning the wheel left/right, while the rear axis is fixed. Bicycles and motorbikes has two critical speeds. Going forward reaching critical speed the bike is self-balancing. Going backwards reaching the other critical speed the bike becomes completely destabilised. This means that reach enough speed going forward and the bike will lean the front wheel into any turn and self-correct raising itself up due to center of mass, rake and newtons first law. Reaching enough speed going backwards and not even the best computerised system can keep the bicycle upright (it becomes complete unstable). So the video is missing a few key elements to a bike, mainly the effect of the rake and the fact that a bike has two critical speeds, one making it stable, one making it completely unstable.

Momentum under a locomotive force, down is forward force.

It has little to do with the center of mass being low, more about the fact that centrifugal force does not exist. When the front wheel turn left or you lean the bike left the front wheel turn more left than than the back wheel, this result in the back wheel continuing its course and thus acting like a force pulling the front wheel back to the right. This plus the energy given from the ground hitting the wheel giving it 2 effects permitting is to lift itself back straight.

I'm a rider (motorcycles) since I was 12 and I did had that question for so many years and I thought that they were so balanced for our safety that they became to safe so you can brake some laws. Maybe I was mistaken 😅

I thought, as the body starts to lean to the side, the center of mass goes DOWN due to both the body shifting to the side and the pole shifting to the side with it. I always figured they use the pole to make the center of mass change and force the person’s body back upright.

With the floppy balancing pole - if the left side goes down two feet - the right side goes up two feet, yes? So how does that alter the centre of gravity of the bike/rider/pole?

Does anyone know where the full episode is?

1:57 also if you think about it, even if the bike speed is really low, so that the wheels are just moving, so that the gyroscopic effect is negligible to it's weight..still the bike stays upright no problem

Neil, I would suggest you buy a book called The Racing Motorcycle by JohnBradley. In it, you will find all the correct information and science as to the dynamics of a bike and how they steer and stay up. It is not how you have been misled and put in this video. This info has been known by bike desugners for decades.

Thanks!

I believe it's all about how the front wheel is designed to castor. i suspect that even if you raise the center of gravity of a bicycle it'll still tend to right itself. The reason a human riding a bike has to actively maintain a balance - by steering the front wheel into the lean, however slightly, at all times - is because the rider is *not* a rigid mass attached to the bicycle; the rider flops around independently and needs to maintain their balance on the bike. That the bike itself is self-righting is what makes the task easier, nay, possible for the human. Here's another attempt, probably inadequate, to explain the self-righting nature of a bike and how its center of mass affects it... When a bike is upright going straight, its center of mass is directly above the bikes track, the track being the path of it's wheels. If the bike leans, then the CoM is no longer above it's track. The front wheel and forks are designed to castor the front wheel and turn the bike to the side the center of mass is on, curving the path of the bike towards that side. This creates a centrifugal "force" which will push the center of mass back towards the bike's track, righting the bike. Think of it as a negative-feedback loop. When a bike is moving in a straight line, the CoM is above the bike's track. If the bike leans, moving the CoM to either side of the track, the bike is designed to automatically create a lateral force to counter that movement, which will push the CoM back above the track. In order to cause a bike to turn, the rider must then counter the lateral counter force to maintain a stable off-track CoM position for the duration of the turn. How's that? Everytime I think of this it boggles my mind how humans (and maybe some animals?) can learn to do this sort of thing instinctively.

1st time I don’t agree with you. Its the caster wheel design that keeps the bicycle dive straight and it will steer in to the turn to right itself if the bicycle made a turn keeping it upright. I discovered that when i was young and drove my bicycle into a curb causing the front wheel fork to bend backwards which made the bicycle unstable because the caster angle was reduced.

tyvm

Also I must add to my previous scientific facts on the way a bicycle 🚲 functions a bicycle 🚴 also takes the human touch. Yet without a person for a long perpetual distance. Great topic ty for sharing. Gentlemen

The same way the Gravity glove 🧤 box functions at the International space station for Astronauts research. Including 💨🛰️ Boosting. Gas jets 😂Amazing I’m glad to comment on this today because my friends it has been record breaking heat today for me yet productive. Star ⭐️ talk is a sigh of relief 😅

The angle of the front fork is what helps to keep straight. It's always tilted to the backwards. Even car front suspension is tilted to back. That's why steering wheel automatically comes straight after turning

How can you ask a question like that ? Gyroscopic action of the wheels and a person's own balance

Question, if you drive a bicycle without your hands, what is the difference between hit a bump and hit a hole of same size and same shape knowing that the back wheel, will push forward? Do you have more chance to fall because of a hole of a bump?

The most surprising part is that you can cancel gyroscopic effect. I can't believe it. I understand why it cancels rotating effect like a double-bladed helicopter without tail blades but canceling gyroscopic effect? Nah, I believe only when I see it.

It's all basically about how the bike is steered. Very slight corrections are continuously made as one is moving forward, which is why you can't really stay upright easily moving backward or remaining motionless. Yes, a bike rolling forward without a rider can self correct as it will steer into a lean --- but watch what happens in reverse.

Niel and Chuck y'all rock! Peace

Hey another question also with the pole on the wire wouldn’t lowering the center of mass essentially be to benefit the balance therefore that’s still the reason?

How can the CM be below the wire for a tightrope walker holding a bar horizontally? No part of either the bar (even a sagging one) or the walker is below the wire, let alone half the mass. If the combined walker+bar CM was below the wire, the system would be stable and there'd be no challenge to tight rope walking. I don't think lowering the CM has anything to do with any of this in the tightrope explanation. What you have is a system where angular momentum is perhaps 0 to start, along with a (simplifying a bit) single vertical force at the walker's feet. If there's a little disturbance and his CM shifts left a little bit, the vertical force is now to the right of his CM which will cause a torque to the left. The walker will start rotating in that direction. By applying an opposite torque to the bar directly, he can induce an opposite rotation in his body and momentarily shift his CM back to the opposite side of the wire. If he moves it far enough and holds it there long enough he can then apply an opposite torque to reverse the rotation of the bar, then stop it when it's level again, thereby canceling the angular momentum in the system. His CM is now back to center and with 0 torque and angular momentum in the walker+bar system until it's disturbed again. There's probably more to it like manipulating the force directions laterally with your feet/legs, maybe doing some lateral translation of the bar and so forth. The point is all this stuff about lowering the CM is irrelevant in the tightrope example. If the CM is above the wire at all by any amount, the system is unstable regardless. Lowering it to a height that's still above the wire won't reverse the torque on the system and stabilize it. The Weeble Wobble also doesn't have much to do with the CM lowering. The reason a Weeble Wobble is stable is because a positional disturbance (say rolling it to the left just like the tightrope walker) pushes the contact point further to the left than the CM moves in that same direction. The vertical force is now far to the left of the CM instead of directly under it which produces a torque in the opposite direction canceling and then reversing the roll velocity. That rights it again. How the CM moved vertically is irrelevant.

The average mass of the battery is about that of the wheel axles; the mass of the motor is near the pedal center. I find my ebike quite stable. Wheels as gyroscopes help in all sorts of riding, on the ground and through the air.