Most People Don't Know How Bikes Work

Most

people

don't

know

how bicycles really

work

. - Let's try it again. So we modified this bike to prove it. This video was sponsored by KiwiCo. More about them at the end of the program. - When you are riding a bike and want to turn left, I think

most

people

just imagine turning the handlebars to the left. This is a bike to check if that's true. And it's made by my friend Rick. and he has a radio controller that allows him to lock the steering to the side. So what he's going to do is, as I'm riding my bike, he's going to choose whether I can turn left or right.

So go ahead. - I'm going to turn left. Pull out the pin, but you can see that you can still turn completely after removing the pin. I have put it together. That's where it crashes. - Well, that's when the LED turns on and says it rotates in that direction. - Turn to the left. - Yes. And if I try to turn right, I can't. And if I try to turn left... - You can do it. - Can. So the question is can I successfully execute this left turn? Should we try it? I mean, it's not going to tell me if it's left or right, so I have to look at the LED to

know

which way I can still turn. - Notify me when you are ready. - Well. (exclaims) No!

It was supposed to be a right turn, but there was no chance. Left. (exclaims) Correct. Alright. (exclaims) Of course, of course, of course! God! - If you look closely, you can see the problem. Here, I'm trying to turn right, but turning in that direction makes me lose my balance. If you could ride this bicycle, you would discover that it is impossible to turn left without first turning right and it is impossible to turn right without first turning left. This seems wrong. I think

most

people believe that you turn a bike by simply pointing the handlebars in the direction you want to go.

After all, that's how you drive a car. Point the front wheels in the direction you want and the car will simply go in that direction. But the difference with a bicycle is that steering doesn't just affect the direction you're going; It also affects your balance. Imagine that you want to turn right and you turn the handlebars to the right. What you have done is effectively steer the bike away from you. You are now leaning to the left and the ground is exerting a force on the bike to the left, so the only way not to fall is to turn the bike to the left.

You have turned left. If you really want to turn right, you must first turn left so you can lean right into the turn. This is something that anyone who rides a bike knows intuitively but not explicitly. - Turn to the left! - Film someone cycling towards you and tell them which direction to turn and you'll discover they turn the opposite way without even thinking about it. - Get out hard! When you ride a bicycle, it is exactly the same as what we call an inverted pendulum or balancing a broom in your hand. If I'm balancing it and start walking towards you, it will always walk away from you.

If I want to walk towards you, it's pretty easy to do and people inherently know how to do it. If I pull it back, I can now start walking in that direction. I have to initiate the inclination to become her. - If you want to move the pendulum somewhere, you first move the base in the opposite direction. And now the pendulum tilts in the direction you want to go so you can move with it. And the same goes for a unicycle. To move forward, you must first go back. So, you lean forward and then you can move forward. - Everything you do on a unicycle is about keeping that contact patch right where it needs to be in relation to you.

You are balancing the broom. The thing is that on a unicycle you do the longitudinal balance with the pedals and the lateral balance, from side to side, just like on a bicycle. Basically, you do a little countersteer to get that weight, to get the contact patch out, and then you can pedal and get it under you. - Now I must point out that sometimes when the steering was locked, we were simply leaning in the correct direction to execute the turn. - Good, good, good, good, good! Good, good, good, good. - Oh, I did it! - Basically by pure luck, we had turned the wrong way before that side of the handlebars locked up.

Now I can move on. - Yes, but don't turn left or they'll screw you. - I can't turn left. The interesting thing about this is that it shows that you can still ride a bike perfectly, right? It's just that you can't turn left. The funny thing is that you couldn't start the turn. I mean, the surprising conclusion is that steering isn't just for turning the bike; Direction is for balance. - That's exactly right. - Why is it difficult to maintain balance on a stationary bike? I think most people think it's because the wheels don't spin, so there's no gyroscopic effect, but that's not all.

The truth is that you use the steering to keep the bike under you, but the steering doesn't

work

when you're stopped. Your balance comes not so much from how you position your body on the bike, but from how you steer the bike to keep it under you. Even when you're going straight, you're constantly making small adjustments in direction to maintain balance. - You are moving the contact patch of the front wheel beneath you. You are doing exactly what you do when you hold a broom balanced in your hand. - So if the rider is responsible for steering the bike to keep it balanced, how do

bikes

stay upright without a rider?

As long as a bicycle moves at enough speed, it can continue to slide indefinitely. I first became aware of this phenomenon through the fantastic MinutePhysics videos, which inspired me to make this video. You should definitely check them out. But it turned out that the terrain where we went to test this effect was very hilly, but the bike still manages to absorb all these disturbances and remain stable. So how is this done? I think most people believe that it's the spinning wheels that create some sort of gyroscopic effect that resists the fall, like in this demonstration of gyroscopic precession.

The wheel remains upright even though gravity pulls it down. But that's not why

bikes

are stable. Just watch what happens when we lock the handlebars completely so you can just go straight. - Locked, locked. Oh! - The only thing that happens is that the address is blocked. You just have to assemble it. You don't have to turn. You just ride. Letting go. - Some people tried to go too fast. (Group laughter) Others experimented with extreme balancing techniques. - He's leaning. Don't go too fast! (Group laughter) - But even with the gyroscopic effect of the wheels, no one was able to keep the bike upright for more than a few seconds. (crowd exclaims) - This is not safe for a second. - It is as difficult to maintain balance on a bicycle with the steering locked as on a stationary bicycle. - No, this is impossible. - Because you can't turn the bike under you.

The real reason bicycles are stable without riders is because they are intelligently designed to steer themselves. If they start to fall to one side, the handlebars rotate in that direction to bring the wheels back under them. At least three mechanisms are responsible for the corrective steering of a bicycle. The first is that due to the angle of the front fork, the steering axle crosses the ground in front of where the wheel touches the ground. So if the bike starts leaning to the left, the force of the ground on the tire turns the wheel to the left.

If the bike starts to lean to the right, the force of the ground pushes the wheel to the right. The front wheel of a bicycle is essentially a swivel wheel, like those found on strollers or shopping carts. Whichever direction you drive them, the wheel aligns and rolls in the same direction. The second reason for corrective steering on a bicycle is that the center of mass of the handlebars and front wheel are located slightly ahead of the steering axis. So when the bike leans to the left, its weight pushes the front wheel to the left. If the bike leans to the right, its weight shifts to the right.

And the third mechanism is a gyroscopic effect but it doesn't keep the bike upright directly; It just helps direct. If you have a gyroscope and you push down on the left side, the gyroscope will spin counterclockwise. If you push down on the right side, it will turn right. This is known as gyroscopic precession. It appears as if the force you apply takes effect 90 degrees from where you applied it. So the bikes are stable mainly thanks to the steering. They have built-in mechanisms to govern themselves. In fact, you don't need all three mechanisms to create a stable bike.

Researchers created this strange looking bike to prove a point. It has no gyroscopic effect thanks to the wheels that rotate in the opposite direction on top of the wheels that touch the ground. Furthermore, there is no trailing effect because the front wheel touches the ground in front of the steering axle. But this bike becomes stable thanks to its mass distribution, the force of gravity that directs it in the direction of any incline. Understanding how bicycles work remains an area of ​​active research. There is a program you can use to input all the different parameters of the bike and see the speed range at which it is self-stable.

And this research is leading to better bikes. This prototype has a smart motor on the handlebars to actively assist steering, keeping the bike upright even at low speeds. I guess it's appropriate that we're still learning new things about bikes, since most of us can ride one without knowing how we actually do it. (futuristic sound effects playing) - Hello, this video is sponsored by KiwiCo, creator of amazing hands-on projects and toys designed to expose kids to STEAM concepts. And with the holidays fast approaching, a subscription to KiwiCo is the perfect gift for any of the young people in your life.

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