How Many Practice?

[Suzukian]

I think, because we all ride, and have survived, we all know what's going on. I had to learn about Gyroscopic Precession when I was designing recumbent bikes, to determine the rake, the offset, and where the contact patch of the front tire would end up at (the rear too, if the bike had a moving suspension swing arm), though it's not as sensitive in the rear.

If you take a bicycle wheel, spin it clockwise, and Hold the top of the axle and bottom, and push forward (away from you) on the top of the axle (with the wheel directly in front of you) and pull towards you on the bottom, the input will be felt 90 degrees after and the right side will drop down. It's always relative to the rotation of the tire. The Pic below explains is best. If you can flip that picture in your mind, then you see why the counter steering drops the bike over towards the 90 degrees ( in that direction)



Gyro_Precession.png

[trent]

Little off topic , but speaking of bicycle wheel.

when I was about ten, my friend and I took off front wheel of my bike, turned my bike upside down
while one of us pedaled the bike by hand to get back tire going the other would put the front tire against back tire holding on each side at the axle...to get it spinning fast.

We thought it was cool how it was hard to move/turn the fast spinning front .

But our real purpose was to see how far it would go when we let loose of it...LOL

[Suzukian]

I used to do that too. I think we all played with rims, wondering why they didn't turn the way we expected. I remember asking my 8th grade science teacher, and he had no idea. Kind of a real duma$$ teacher, but he was known for that. He had given up a long time ago.

[Dogma]

There is some misinformation floating around in this thread. Gyroscopic precession is not what makes a bike lean over, though it is a secondary effect that makes a small contribution. Test bikes have been built to demonstrate this. As with many things, there's more than one thing going on, so it's incorrect to try to simplify it to one thing.

Anyhow, what matters to this thread is not whether you think you understand the mechanics of cornering, but whether you've trained yourself to the correct actions and reactions. Cogitating about the physics is far too slow. Bike handling has to happen without thinking. Again, the real world is too complex for there always to be one way to do a thing. Some situations call for leaning one way, some call for another.

[1978GS750E]

There is some misinformation floating around in this thread. Gyroscopic precession is not what makes a bike lean over, though it is a secondary effect that makes a small contribution. Test bikes have been built to demonstrate this. As with many things, there's more than one thing going on, so it's incorrect to try to simplify it to one thing.

Anyhow, what matters to this thread is not whether you think you understand the mechanics of cornering, but whether you've trained yourself to the correct actions and reactions. Cogitating about the physics is far too slow. Bike handling has to happen without thinking. Again, the real world is too complex for there always to be one way to do a thing. Some situations call for leaning one way, some call for another.

But, but......we've heard so much about it! And to think I spent all that time studying Gyroscopic precession. Guess I'll never fly my helicopter now!

[Suzukian]

You cannot equivocate fact. Gyroscopic precession followed with you leaning over, and controlling that moment is what leans the bike over, working with centripital force and centrifugal force. The conversation started out about counter steering.Gyroscopic precession works with centripital and centrifugal force, that is acting on the center of mass of the motorcycle that is induced by the contact patch of the tire. As long as the tires holds, the centripital force will allow you to turn, pushes you down into the seat, this is canceled by the centrifugal force, which is trying to push you outwards, both cancel each other until more speed is added (from torque), which increases centrifugal force because of torque, and all equalizes once the speed is no longer accelerating. When the lean angle increases, more torque is needed to hold the bike up, which creates more centrifugal and centripital force, a balance is achieved, this happens back and forth.

How does the centrifugal force keep the bike up? The answer is torque. Even if the forces cancel out in the rotating frame of reference (see pic above for frame of reference), their torques in the case of a turning motorcycle do not.

The centrifugal force acts on the center of mass of the bike, this creates a torque that rotates the bike with the tires acting as the pivot point – like hinges, for example. If the lean angle increases, we need a bigger centrifugal force to keep the motorcycle from falling. But a bigger lean angle (with all else being equal) induces a larger centripetal force (as you are now leaning towards the center of the radius), and from faster turning. The faster turning can also be seen as a higher angular velocity in the rotating frame of reference in the pic above, and thus we get the required increase in the centrifugal force to compensate for the increased lean angle. There is no magic in motorcycling, but there are certainly physics.

When you experience "G's" in an airplane, you experience Centripital force, your "G's" are caused by the planes wings holding you against the plane. If you are on the end of a rope, being spun, you experience centrifugal force, that's the difference between the two. Motorcycles are in a unique situation where both these forces are in play, and balance out to give us stability, the torque of the engine gives us the centrifugal force, and the lean angle generates the centripital force. Gyroscopic Precession with a little leaning allows the process to start.

You don't need to know this to ride a bike. It's what's happening though, and the people who design these bikes work these "'sines and cosines" to make a bike handle a certain way. Without knowledge of physics as how these bikes work, bike would handle horribly. When you see people swapping the front end of bikes, the first thing the look at is the triple tree offsets to see if they match, or will be close enough to work. Otherwise you would make a very dangerous handling bike.

Helicopters that had experimented with jets on the tips of the blades experienced no torque whatsoever, and did not need tail rotors, except to change direction. Gyrocopters with unpowered rotary wings produce no torque, though they still experience gyroscopic precession. If you don't understand it, it doesn't mean it doesn't exist.

As I stated before, you feel these things and if you have the skill to ride a bike, your muscles and balance tell you what to do. You can live your life without knowing why, but knowing why does allow you to do things, and take your bike over with a better understanding of what is going on. You don't think about it as your doing it, but certainly, as we all can walk and chew gun at the same time, we can think about what is actually happening between our legs at extreme lean angles, and just possibly know that you may be coming on a mistake, or doing everything just the way you should be doing it.

Practicing your Brain's ability to think is just as necessary as practicing on how to physically ride a bike. This thread is about practicing. It follows that one may want to understand how what they are practicing works.


1978GS750E, You can fly a helicopter. Anyone who can ride a motorcycle is the best candidate for a helicopter license. Go take a lesson or two. You may surprise yourself. I sure as heck enjoyed it.

[trent]

, You can fly a helicopter. Anyone who can ride a motorcycle is the best candidate for a helicopter license. Go take a lesson or two. You may surprise yourself. I sure as heck enjoyed it.

If its as easy as flying drones, I'm in..LOL

I remember years ago flying some drones or remote control aircraft , had to really stay in top of what you were doing

But drones over last decade almost fly themselves.
so many safety feature.

I had a bird attack my smallest drone, it tumbled toward the ground, which was asphalt, I thought it was the end of my little drone
But right before it hit the asphalt ,like a foot before, it saved it self.

went up to four foot and waited for me to fly it away..

flying car...just a person sized drone.. lol

[Rob S.]

You cannot equivocate fact. Gyroscopic precession followed with you leaning over, and controlling that moment is what leans the bike over, working with centripital force and centrifugal force. The conversation started out about counter steering.Gyroscopic precession works with centripital and centrifugal force, that is acting on the center of mass of the motorcycle that is induced by the contact patch of the tire. As long as the tires holds, the centripital force will allow you to turn, pushes you down into the seat, this is canceled by the centrifugal force, which is trying to push you outwards, both cancel each other until more speed is added (from torque), which increases centrifugal force because of torque, and all equalizes once the speed is no longer accelerating. When the lean angle increases, more torque is needed to hold the bike up, which creates more centrifugal and centripital force, a balance is achieved, this happens back and forth.

How does the centrifugal force keep the bike up? The answer is torque. Even if the forces cancel out in the rotating frame of reference (see pic above for frame of reference), their torques in the case of a turning motorcycle do not.

The centrifugal force acts on the center of mass of the bike, this creates a torque that rotates the bike with the tires acting as the pivot point – like hinges, for example. If the lean angle increases, we need a bigger centrifugal force to keep the motorcycle from falling. But a bigger lean angle (with all else being equal) induces a larger centripetal force (as you are now leaning towards the center of the radius), and from faster turning. The faster turning can also be seen as a higher angular velocity in the rotating frame of reference in the pic above, and thus we get the required increase in the centrifugal force to compensate for the increased lean angle. There is no magic in motorcycling, but there are certainly physics.

When you experience "G's" in an airplane, you experience Centripital force, your "G's" are caused by the planes wings holding you against the plane. If you are on the end of a rope, being spun, you experience centrifugal force, that's the difference between the two. Motorcycles are in a unique situation where both these forces are in play, and balance out to give us stability, the torque of the engine gives us the centrifugal force, and the lean angle generates the centripital force. Gyroscopic Precession with a little leaning allows the process to start.

You don't need to know this to ride a bike. It's what's happening though, and the people who design these bikes work these "'sines and cosines" to make a bike handle a certain way. Without knowledge of physics as how these bikes work, bike would handle horribly. When you see people swapping the front end of bikes, the first thing the look at is the triple tree offsets to see if they match, or will be close enough to work. Otherwise you would make a very dangerous handling bike.

Helicopters that had experimented with jets on the tips of the blades experienced no torque whatsoever, and did not need tail rotors, except to change direction. Gyrocopters with unpowered rotary wings produce no torque, though they still experience gyroscopic precession. If you don't understand it, it doesn't mean it doesn't exist.

This is why, when my 90 year old grandfather asked me why motorcycles don't fall when they lean so far over, I didn't know what to say. What would inertia or centrifugal force mean to someone born in small town 1880's Russia? (Ukraine, actually).

[rphillips]

Rob, you may need to get another pack of index cards.

[Suzukian]

This is why, when my 90 year old grandfather asked me why motorcycles don't fall when they lean so far over, I didn't know what to say. What would inertia or centrifugal force mean to someone born in small town 1880's Russia? (Ukraine, actually).

The same thing. This stuff was figured out a very very long time ago. I wonder how far you are from New Fairfield?

[Suzukian]

If its as easy as flying drones, I'm in..LOL

I remember years ago flying some drones or remote control aircraft , had to really stay in top of what you were doing

But drones over last decade almost fly themselves.
so many safety feature.

I had a bird attack my smallest drone, it tumbled toward the ground, which was asphalt, I thought it was the end of my little drone
But right before it hit the asphalt ,like a foot before, it saved it self.

went up to four foot and waited for me to fly it away..

flying car...just a person sized drone.. lol

Drones have come a long way. I have a really expensive one (well, my son and I), it will come and land back to it's start point when it senses the battery level is at that point. It has a 1080P focusing and pivoting camera. It's way ahead of what I know how to do. I would have to have someone take me through it, I just don't have time. Time is slipping through my fingers at an incredible rate. Drones are really excellent. I have a couple of R/C copters that have no gyroscopes, and are, well, a handful to fry, but fun as Heck!!! Just doing a Chandelle in them is a great accomplishment.

[Suzukian]

Addendum: You aren't in a drone, like you are when piloting a Helicopter, in that sense, Helicopters are easier. Of course, if you mess up, your teacher takes over, or you die.

[storm 64]

How long are we going to beat this dead horse?
Let it go man...

[trent]

How long are we going to beat this dead horse?
Let it go man...

I thought we were just giving it CPR? LOL

[ptegsotic]

How long are we going to beat this dead horse?
Let it go man...

this site has an excellent history of weeding out the bloviating BS, eventually.
patience grasshopper