Pillar of Wisdom - Gyroscopic forces...not

[Slowbee]

damn, can't get this embedding thing right. Here's the link

 

http://www.youtube.com/watch?v=Cbfe2_2DDc0

 

stuff that for kids, I need one! anything to stay more upright

[Johan Bornman]

damn, can't get this embedding thing right. Here's the link

 

http://www.youtube.com/watch?v=Cbfe2_2DDc0

 

I'm not sure if the video answers this question but I'll ask nevertheless.

 

1) What is the mass of the internal gyro and

2) What direction is the internal gyro spinning?

 

I can deduce the answer to question which is in the opposite direction and that's not what's happening in our Sani2C bike.

 

Different issue.

[Johan Bornman]

Hands up. Who has tried to balance a broomstick this afternoon yet and made the analogy with a bike?

[nolipoli]

I have balanced many broomsticks...

 

On the counter steering thing:

If my broomstick was perfectly balanced, it would be upright and static. If I wanted it to fall over to the right, I would have to alter that state of balance by moving the bottom to the left, hence the counter steering argument.

[BergForce]

Counter steering is something different. Counter steering is used while going around a corner to prevent the vehicle from spinning out. This is not the same as turning a bit left to make you lean to the right better when entering a corner.

[Johan Bornman]

I have balanced many broomsticks...

 

On the counter steering thing:

If my broomstick was perfectly balanced, it would be upright and static. If I wanted it to fall over to the right, I would have to alter that state of balance by moving the bottom to the left, hence the counter steering argument.

Naah. You can steer without counter steering. I cited the experiment. Do it.

[BergForce]

Naah. You can steer without counter steering. I cited the experiment. Do it.

 

But you can turn in quicker/better by 1st destabilizing the bike by slightly turning it in the opposite direction slightly 1st.

[Johan Bornman]

But you can turn in quicker/better by 1st destabilizing the bike by slightly turning it in the opposite direction slightly 1st.

Why not just destabilize it in the direction you want to turn. Then you save even more time.

 

Start another thread on that and I'll tackle it there. This thread is about ratcheting to gain momentum without gaining speed and, how a bike balances and does not balance.

[BergForce]

Why not just destabilize it in the direction you want to turn. Then you save even more time.

 

Start another thread on that and I'll tackle it there. This thread is about ratcheting to gain momentum without gaining speed and, how a bike balances and does not balance.

 

Because it will throw your weight too much in the opposite side of which you are turning.

 

Agreed, but no need to tackle this one it is very easy to test on your bike.

[Helpmytrap]

But you can turn in quicker/better by 1st destabilizing the bike by slightly turning it in the opposite direction slightly 1st.

You make it sound like two separate steps. Counter steering to turn left, (at speed) you push on the left of the handlebar and you go left. It is one step.

Edited June 10, 2013 by Helpmytrap

[Johan Bornman]

You make it sound like two separate steps. Counter steering to turn left, (at speed) you push on the left of the handlebar and you go left. It is one step.

 

If you do the wheel experiment and envisage all this counter-steering stuff, you'll see that leaning and counter steering produces exactly the same effect. The one causes the other. However, we all prefer (maybe some exception), to just lean.

[DJR]

Hands up. Who has tried to balance a broomstick this afternoon yet and made the analogy with a bike?

I asked my mother in law and she says your whole argument about balancing a broom is rubbish. She simply balances on her broomstick and says it is easier the faster she goes!

[HappyMartin]

I rode motorbikes for years. Counter steering is the quickest way to get the bike over. Once it dips into the turn you lean with it. I do the same on the road bike in fast corners. No idea on MTB. Too much going on and if I think at all I end up in casualty. Sometimes end up there anyway.

 

If you don't mind Johan please explain to me, I'm not good at this stuff as you will hear, what are the practical implications of all this gyro stuff that does not work as we think it does. It still seems to me that speed is my friend whatever the physics behind it might be.

[RexFuzzle]

I remember watching an episode of QI where they discussed why a bicycle stays upright and all the normal gyro arguments etc were thrown around and Fry said that the exact reason for it staying upright is not known. Googling this now hasn't yielded much, but it seemed believable at the time.

[Johan Bornman]

I rode motorbikes for years. Counter steering is the quickest way to get the bike over. Once it dips into the turn you lean with it. I do the same on the road bike in fast corners. No idea on MTB. Too much going on and if I think at all I end up in casualty. Sometimes end up there anyway.

 

If you don't mind Johan please explain to me, I'm not good at this stuff as you will hear, what are the practical implications of all this gyro stuff that does not work as we think it does. It still seems to me that speed is my friend whatever the physics behind it might be.

Just do the wheel experiment like I so laboriously spelt out. Try it, then ask specific questions. I really can't explain better than that.

[Brian Fantana]

Without arguing with any of the previous posts, I believe that it is not only your body that keeps your bike upright when you are riding at higher speed, lets say 20km/h +.

 

Your bike geometry, especially the head angle will help you as well. The fact that all bikes I know of have head angles slacker than 90º dictates that a bike will "try" to keep itself straight when travelling at a fair speed. The head angle of a bike is similar to the Kingpin Inclination angle on a car, which is where the self centering action of a car's steering comes from. Imagine trying to ride no hands with a bike with a 90º head angle, it will be very challenging.

 

However, the forces described above are small relative to the weight of the rider (weight not mass). So although the head angle plays a part to keep the bike upright, the intuitiveness(which is a very natural thing) of the rider plays a bigger role in keeping the bike upright.