Countersteering confusion : (

Discussion in 'The Perfect Line and Other Riding Myths' started by IrishJohn, Dec 30, 2012.

  1. lnewqban

    lnewqban Ninjetter

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    I cannot forget because I am not thinking.

    My bike just rolls to the left each time I go to full left lock and lift my feet up from stopped vertical position.

    Just try it and report back :1drink
  2. Fajita Dave

    Fajita Dave Been here awhile

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    Due to the geometry of a motorcycle when you turn the handlebars left the tire's contact patch moves to the left of the CG. Because of this there is less weight being supported on the motorcycle right side. So the motorcycle will lean right when you turn the handlebars left even at a dead stop.

    Being completely stopped and trying to balance 300+ pounds on a round surface with a 150+ Lbs lump of meat moving it around makes it extremely difficult to tell whats going on. If you lift one foot up a fraction of a second sooner than the other, the results will not be accurate. Not to mention your influence on the handlebars, if you pushed off slightly with one foot and which cheek of your back side you prefer to sit on (hardly anyone sites exactly centered on their seat). Its much easier and more accurate to look at what is mechanically going on which I explained in the first paragraph.

    And yes I have tried it.
  3. joexr

    joexr Banned

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    Thanks , I agree. I didn't have to try it to see either , I understand the geometry.
  4. joexr

    joexr Banned

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    What the hell are you doing this on?
  5. lnewqban

    lnewqban Ninjetter

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    Sorry, Dave, that is not how it works for my bike.
    It is very evident, no hesitation or doubt, the bike falls on the left side each time, if it is close to vertical.

    If you reconsider the steering geometry, you could see that the trail means that the contact patch is aft the steering axis a few inches and that it rotates off center the bike, but in the opposite direction toward which the handlebar steers.
    As the front contact patch remains planted on the ground, the steering head column moves a little sideways toward the direction in which the handlebar steers.
    It happens in cars as well.

    http://www.dinamoto.it/dinamoto/8_on-line_papers/wobble-weave/wobble.gif

    For any bike, the CG remains aligned with the frame of the bike (between rear contact patch and the ground's projection of the axis of the steering column).

    Playing with the handlebar is how Police riders can keep balance at extremely low speeds.

    Not trying to prove you wrong, Sir, just making you take a closer look.
    I have agreed with all your previous posts that I have read in this forum; there is no reason for not agreement on this point, IMHO.
  6. joexr

    joexr Banned

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    You car falls over when you turn the wheel?:rofl
  7. Dolly Sod

    Dolly Sod Red Clay Halo

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    Tried this on my Weestrom and 640 adventure. Both bikes seemed to have a 50/50 chance of falling toward or away from the direction I turned the bars when balancing at a standstill. Nothing consistent or obvious.
  8. joexr

    joexr Banned

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    I tried it in the car , but it doesn't want to fall over either way.:lol3 There's the possibility we're not drinking enough.
  9. Fajita Dave

    Fajita Dave Been here awhile

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    I'm all for constructive conversations! Arguing never gets anywhere.

    Everything you said is absolutely right but I still see it as causing a "counter-steer" type reaction. As you said if you turn the handlebars right the steering column moves right. Due to the laws of inertia that movement alone would cause the motorcycle to lean left. An object at rest tries to stay at rest. If you move the steering column right but the chassis of the motorcycle tries to stay at rest, it will offset how the weight is being distributed from being centered (before steering movement) to offset to the left (after turning the handlebars right). This causes the motorcycle to lean left when the handlebars are turned right even at a stand still.

    The link you provided of the bicycle is leaving out one very important aspect which is tire profile. When the steering is straight the contact patch of the tire is centered in the middle of the tread and in line with the wheel's axle. Because of the rake angle built into a motorcycle when you turn the handlebars the tire leans over and the contact patch is now offset from center. If you turn the handlebars right, the contact patch now moves off of center and to the right of the tire tread. This changes the center of gravity slightly because the contact patch is no longer centered with the wheel axle. This isn't a perfect analogy but I can't think of a better one right now. Imagine balancing a horizontal beam at its center. If you push the beam off that balance point from the right side, the beam will fall to the left.

    There is something I could be missing or wrong about. I'm an experience mountain biker and doing track stands from a rolling stop differ from your experience. If I feel my balance falling to the right, I turn the handlebars right which cause the bike to lean back left extremely slightly to hold balance.
  10. lnewqban

    lnewqban Ninjetter

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    No, no, Joe !!!
    I referred to the little yaw of a car body when the tires are turned all the way to the left.
    That is the whole reason of the trail in bicycles, shopping carts, tractors, cars, motorcycles, etc.: to naturally bring the contact patch of the tires to be in line with the axis around which they rotate to steer, so the vehicle has some directional self-stability.

    You may not bother reading more about it, but for whoever else is interested:
    http://en.wikipedia.org/wiki/Caster_angle#Trail_or_trailing

    I understand your explanation, Dave, and I appreciate it.

    Thanks, Boon.
    It seems that it does not work the same for every bike then.


    It works as I described for my Ninja 250, reason for which I stand behind the concept that I tried to share via that little experiment, responding post #690 quoted above.

    Starting moving from full left lock and vertical position, my bike tends to roll to the left first and then, while the speed increases, it rolls to the right.
    If I keep moving it slow enough, there is no counter-steering effect.

    That has been my experience; however, according to other posters, it seems to happen in a different way for heavier bikes with wider tires, I don't know.
  11. David R

    David R I been called a Nut Job..

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    Riding my motorcycle coming to a stop. Right foot on the brake, left foot as landing gear.

    IF the bike does not want to lean to the left so my left foot can catch it, I TURN TO THE RIGHT so the bike falls to the left. Do not speculate go ride the bike and see for your self.

    David
  12. Dirty in all

    Dirty in all Adrenaline Junkie

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    Sitting in my normal riding position on a KTM 500 EXC with supermoto setup (that's 17" wheels for the most part) ... balance, pick my feet up, turn left, bike falls 50/50 left or right. If I sit forward or lean forward, balance, pick my feet up, turn left, bike falls left. Sit back or lean back, balance, pick my feet up, turn left, bike falls right.

    :wave

    Think Im going to unsubscribe from this thread before my wife divorces me because Im in the garage acting out scenarios trying to settle an argument between me and myself.
  13. Fajita Dave

    Fajita Dave Been here awhile

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    This will probably sound like a snide remark but answer me this. If the underlined statement is what you're experiencing then at what point does turning the handlebars do absolutely nothing?

    From your experience at some point there needs to be a transition from direct steering to counter-steering. This means if you were to ride right in that transition point, steering will do absolutely nothing.
  14. joexr

    joexr Banned

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    [From your experience at some point there needs to be a transition from direct steering to counter-steering. This means if you were to ride right in that transition point, steering will do absolutely nothing.[/QUOTE]:roflThis is a classic.
  15. pretbek

    pretbek Long timer

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    Now you know why so many inexperienced riders -including some that have been riding for decades- go virtually straight in a turn that is to them unexpectedly tight.
    They were all riding at that transition point, no amount of steering could get them through that turn.
  16. lnewqban

    lnewqban Ninjetter

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    Good question, Dave.
    At full left lock the bike turns to the left regardless the speed.

    If the speed is low enough, my bike rolls or tends to fall to the left, while it still turns to the left.
    There is a unique speed at which it will balance in a lean angle.

    If the speed increases, my bike rolls or tend to fall to the right, while it still turns to the left.
    If I do nothing to support it with my right foot, it will fall on the right side while describing a left turn.

    There is a unique speed (call it transition speed if you will) at which the bike stays vertical while turning left.
    Left steering will do something: to make the bike describe a left hand circle.
    This is very difficult to achieve, due to body's movements and precise throttle, but not impossible.
  17. Fajita Dave

    Fajita Dave Been here awhile

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    The motorcycle will always turn in the direction the front wheel is pointing (unless its off the ground or sliding). This is steering and for the most part how motorcycles turn just like cars do. You might be getting one thing confused here. When you are riding a motorcycle and turning left, the front wheel is point left no matter what speed you are traveling. Counter-steering only changes your lean angle which allows you to turn sharper, go straight or anything in between.

    I'm going to throw a variable into the experiment you mentioned. Your experiment was to turn the handlebars left till the lock and then ride very slowly (lets say around 1mph or less). For you the motorcycle still fell left and I assume it fell pretty slowly at first and gained speed the further it fell right?

    Now throw this variable in there and tell me your results. Ride with the handlebars locked left just like before at 1mph or less (same as your experiment). Only this time the moment the motorcycle begins to fall left, immediately turn your handlebars to the right. Tell me the results of what you feel. Make sure your left foot is ready to catch you.
  18. lnewqban

    lnewqban Ninjetter

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    Maybe I didn't understand your previous question, Dave; so, we agree on that: left steering = left turning, ..........as long as the two patches are planted on the road (sand doesn't care what your steering is).

    The rolling is our point of discussion then.

    This is how I see it:
    1) Bike that turns generates a centrifugal force.
    2) Bike that doesn't lean to compensate that centrifugal force with its weight, falls away from the center of the turn.
    3) Bike that turns in steady way must be at a lean angle that perfectly balance centrifugal force and weight force.
    4) Making a bike going on a straight line roll is best achieved by making the bike turn.


    My trivial point for explaining the above question about the velocity at which steering becomes counter-steering is based on the magnitude of the centrifugal force.
    For zero mph, that force doesn't exist; only the weight does.
    For zero mph, that weight force moves off-center as I turn the steering bar (at least for my motorcycle), inducing a rolling moment toward the side the steering bar was turned.
    For very low speeds, the roll moment induced by that centrifugal force (note that it depends on the square of speed) is weaker than the roll moment induced by the off-center weight (at least for my motorcycle).

    [​IMG]

    According to above posts, including yours, what I have explained doesn't happen for other types of motorcycles.
    For those bikes, due to steering geometry and wider tire profile, the weight moves off-center toward the same direction in which centrifugal force points and in opposite direction to the steering input.
    For such bikes, there is no transition speed, as soon as, and even before, the bike starts moving, counter-steering is happening.
  19. señormoto

    señormoto Supermoto Abuser

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    Here's a visual representation for any noobs that still don't get it:

    [​IMG]
  20. henshao

    henshao Bained

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    Somebody mentioned earlier in the thread that the front wheel/tire is always pointing in the direction that the bike is turning unless it is sliding or off the ground. In order to add some confusion to the thread I want to talk about the in-turn counter-steering. We have established that you have to countersteer to initiate a lean. Once you are leaning you have to countersteer to prevent the bike from falling on it's side (especially at low speeds. This is what I posit confuses people about the mythical steering/counter-steering transition speed. At very low speeds, once the bike is turning you have to steer very hard into the turn to prevent the bike from falling. The initial counter-steer compared to the in-turn counter-steer is nearly imperceptible.)

    Some people describe their bikes as very eager to turn or very eager to stand up and go straight while turning. They describe their bikes as having to be "Held down" in a turn. If their bike is actually trying to stand up and has to be continuously counter-steered into the turn I wonder if the front wheel is actually pointing into or away from the turn. Due to the flexible nature of a tire it is possible that the tire is not slipping so much as the contact patch is flexing and rotating in relation to the rest of the tire.