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09-03-2013, 03:08 AM   #991
DudeClone

Joined: Nov 2010
Location: here, there, everywhere
Oddometer: 1,855
Quote:
 Originally Posted by lnewqban Not exactly. While we roll over a straight line, the weight vector starts at the CG (combined rider+bike) and points vertically down and aligned with our support points: the contact patches. We are in vertical balance. As soon as we deviate from a straight line trajectory, the vector weight tilts from the CG toward the outside of the turn or curvilinear trajectory. The faster we roll and the smaller is the radius of the circular trajectory, the bigger is the angle of deviation from vertical of that vector. We people like complicating things, so we decompose that vector into weight and centrifugal force, but in reality that tilted vector is the actual force that the bike feels. Suddenly, we are out of balance and our contact patches are not aligned with that vector. We need to roll over the bike in order to re-gain that comfortable balance. ..............but how can we?

oh shit, maths
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bikes

 09-03-2013, 04:05 AM #992 dazeedmonds Gnarly Adventurer     Joined: Jun 2013 Oddometer: 142 Ok, Having sobered up some this is getting confusing again.... But throughout the turn our contact patches are out of line with the bike, turning the wheel farther into the turn brings the front wheel contact patch under the bike, bringing the bike upright?
 09-03-2013, 04:20 AM #993 henshao Bained     Joined: Jun 2013 Location: The Commonwealth Oddometer: 610 Driving a car. You turn the wheels right, it leans to the left. Same thing with motorcycles. Put a drink in your cup holder, filled to the brim and investigate.
09-03-2013, 05:35 AM   #994
lnewqban
Ninjetter

Joined: Jan 2012
Location: Florida
Oddometer: 291

Quote:
 Originally Posted by dazeedmonds Ok, Having sobered up some this is getting confusing again.... But throughout the turn our contact patches are out of line with the bike, turning the wheel farther into the turn brings the front wheel contact patch under the bike, bringing the bike upright?
No Math, no lean, no turn yet.

We are approaching a right hand turn and we know that as soon as we direct the front tire to follow the trace of the right turn (a circular movement), the weight is going to tilt toward the left (due to gyroscopic precession and centrifugal force), putting us out of balance.
Remember: we need to roll over the bike to the right (as we start turning and as the weight vector tilts left) in order to keep that comfortable balance.
..............but how can we?

Then, we use the only thing that we can control with some authority: a turn of the handlebar.
As explained above, if we turn that bar right, we are going to be immediately out of balance, falling on our left side.
If we don't turn the handlebar, we are going to continue going straight and out of the road: no good either.
If we turn the handlebar to the left (pushing the right hand-grip) as the turn begins, we are starting a left turn and making the weight vector tilt toward the right: we are now out of balance and falling, rolling over or leaning the bike to the right (which is exactly what we needed!!!).

Right after the bike is falling to the right and acquiring the right lean angle that we needed to turn right, we can use that rolling inertia that keeps the bike falling to the right in our benefit, not needing that weight vector to be tilted toward the left anymore.

Is only now (some fractions of a second after we steered left) that we can steer to the right, just like we do in a car, making the front tire follow the trace of the curve for as long as it lasts.
By doing that, we are making the weight vector tilt toward the left and getting aligned with both contact patches.
We are in balance again !!! ............not vertically but leaned.
During the turn, we are feeling a little heavier than normal: that is due to the fact that the vector weight gets bigger as it tilts, the more it tilts, the more it grows.
If that curve and speed call for 45 degree lean, the bike and the rider weight 40% more.

We need to revert the direction of the steps in order to abandon the circular movement and lean angle at the end of the curve, resuming linear trajectory.

lnewqban screwed with this post 09-03-2013 at 07:58 AM

09-03-2013, 06:40 AM   #995
farmerstu

Joined: Apr 2011
Location: Minnesota west central
Oddometer: 527
Quote:
 Originally Posted by henshao Driving a car. You turn the wheels right, it leans to the left. Same thing with motorcycles. Put a drink in your cup holder, filled to the brim and investigate.
great analogy. I'll remember it.

I think the last few posts are what hippie and joethe bestestfastesgoodestriderontheplanet are complaining about. interesting but not needed for learning how to steer a motorcycle.

09-03-2013, 07:00 AM   #996
Center-stand

Joined: Nov 2008
Oddometer: 800
Quote:
 Originally Posted by dazeedmonds ................................... Try this: In a SAFE place initiate a lean by counter steering. Then release all input in the direction of the lean, unless you are far enough over that the camber of the tires will carry you through the turn, the bike will right itself. You actually have to continually apply the same amount of pressure throughout the duration of the turn to maintain the turn. That is the gyroscopic action at work.
Actually the bike will not right itself. I know we have the perception that it does, but in reality we are making steering input and micro adjustments all the time, the righting of the bike is because of our input.

Did you read this? There is a short segment that explains it much better than I can..
http://www.manicsalamander.com/artic...cycle-(!).aspx

..

09-04-2013, 03:35 PM   #997
Klay

Joined: Nov 2005
Location: right here on my thermarest
Oddometer: 102,758
Quote:
 Originally Posted by dazeedmonds The gyroscopic action of the wheels does help balance the motorcycle, however the same gyroscopic properties are WHY counter steering works.

Negative. Gyroscopic forces are a smaller secondary effect. Countersteering would work with no gyroscopic forces at all.

09-04-2013, 05:58 PM   #998
hippiebrian

Joined: Jun 2012
Location: Long Beach, Ca.
Oddometer: 3,883
Quote:
 Originally Posted by Klay You countersteer at all speeds. There is no lower limit.
From a full stop, make a u turn and pay attention to what you are doing with the handlebars. If you are countersteering at that point, you are eitgher going the wrong way or are falling.

Which makes my point. Steering a bike, wether it's by direct input at slow speeds or by countersteering at most speeds, is almost instinctual. If you can make a bike change direction, you really don't need to know the physics behind it. You DO need to practice.

09-04-2013, 06:20 PM   #999
Boon Booni
Red Clay Halo

Joined: Aug 2003
Location: Richmond, Va
Oddometer: 13,786
Quote:
 Originally Posted by hippiebrian From a full stop, make a u turn and pay attention to what you are doing with the handlebars. If you are countersteering at that point, you are eitgher going the wrong way or are falling. Which makes my point. Steering a bike, wether it's by direct input at slow speeds or by countersteering at most speeds, is almost instinctual. If you can make a bike change direction, you really don't need to know the physics behind it. You DO need to practice.
Negative. Turning from a full stop you lean the bike with your feet before pulling away. If you were to keep the bike perfectly upright with your feet and pull away with the bars at full left lock, you would fall over to the right.

09-04-2013, 06:22 PM   #1000
dazeedmonds

Joined: Jun 2013
Oddometer: 142
Quote:
 Originally Posted by hippiebrian From a full stop, make a u turn and pay attention to what you are doing with the handlebars. If you are countersteering at that point, you are eitgher going the wrong way or are falling. Which makes my point. Steering a bike, wether it's by direct input at slow speeds or by countersteering at most speeds, is almost instinctual. If you can make a bike change direction, you really don't need to know the physics behind it. You DO need to practice.
Right. Practice. And KNOW that pushing right can get you farther over in a right hand turn. Why exactly it happens is an interesting exercise in brain aerobics.

09-04-2013, 06:28 PM   #1001
hippiebrian

Joined: Jun 2012
Location: Long Beach, Ca.
Oddometer: 3,883
Quote:
 Originally Posted by Boon Booni Negative. Turning from a full stop you lean the bike with your feet before pulling away. If you were to keep the bike perfectly upright with your feet and pull away with the bars at full left lock, you would fall over to the right.

Whenever I make a u turn from a stop, i turn the handlebars in the direction I'm going. Of course I lean the bike, otherwise I wouldn't turn, but that wasn't my point. My point is that countersteering does not work at all speeds.

Most of what we do on a motorcycle, steering wise, is done without thinking. It's the same things we did on a bicycle without knowing what we were doing. That is my point.

09-04-2013, 07:26 PM   #1002
brian.ict

Joined: Oct 2011
Location: Wichita
Oddometer: 22
Quote:
 Originally Posted by hippiebrian Whenever I make a u turn from a stop, i turn the handlebars in the direction I'm going. Of course I lean the bike, otherwise I wouldn't turn, but that wasn't my point. My point is that countersteering does not work at all speeds. Most of what we do on a motorcycle, steering wise, is done without thinking. It's the same things we did on a bicycle without knowing what we were doing. That is my point.
Nope. If you're on two wheels and not using your feet, countersteering initiates the turn whether you believe it does or not.

09-04-2013, 07:31 PM   #1003
Boon Booni
Red Clay Halo

Joined: Aug 2003
Location: Richmond, Va
Oddometer: 13,786
Quote:
 Originally Posted by hippiebrian Whenever I make a u turn from a stop, i turn the handlebars in the direction I'm going. Of course I lean the bike, otherwise I wouldn't turn, but that wasn't my point. My point is that countersteering does not work at all speeds. Most of what we do on a motorcycle, steering wise, is done without thinking. It's the same things we did on a bicycle without knowing what we were doing. That is my point.

If you lean the bike with your feet before you ride off from stop there's no reason to counter steer. That's because you counter steer to induce a lean and you've already leaned the bike with your feet!

Counter steering works at all speeds above zero.

There is not speed at which you change from direct steer to counter steer. As soon as you move forward and lift your feet you counter steer to balance and turn.

Leaning the bike doesn't turn the bike. Leaning the bike keeps it from falling over toward the outside while turning.

09-04-2013, 08:20 PM   #1004
hippiebrian

Joined: Jun 2012
Location: Long Beach, Ca.
Oddometer: 3,883
Quote:
 Originally Posted by Boon Booni If you lean the bike with your feet before you ride off from stop there's no reason to counter steer. That's because you counter steer to induce a lean and you've already leaned the bike with your feet! Counter steering works at all speeds above zero. There is not speed at which you change from direct steer to counter steer. As soon as you move forward and lift your feet you counter steer to balance and turn. Leaning the bike doesn't turn the bike. Leaning the bike keeps it from falling over toward the outside while turning.
Try it and get back to me.

09-04-2013, 08:38 PM   #1005
Boon Booni
Red Clay Halo

Joined: Aug 2003
Location: Richmond, Va
Oddometer: 13,786
Quote:
 Originally Posted by hippiebrian Try it and get back to me.
I do it every day. All the time. Over and over.

Tried it and tried it and tried it again. Always the same, counter steer to balance, counter steer to initiate a turn. If it wasn't that way, then it would be just as easy to balance while stopped as it is while moving 2 mph.

Why is it easier to balance when moving 2mph than when completely stopped? Counter steering.

Counter steering is how we balance, and it's how we initiate a lean.

Not gyroscopes, not shifting your weight, but turning the bars and counter steering.

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