Countersteering confusion : (

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

  1. Fajita Dave

    Fajita Dave Been here awhile

    Joined:
    May 13, 2007
    Oddometer:
    717
    Location:
    Barboursville, VA
    +100 I didn't know what counter steering was (much less the laws of physics!) for years when I rode motorcycles. The only thing learning about how it worked did for me was help with the confidence than I do know what I'm doing. That confidence has proven to be priceless a few times though.
  2. Jedl

    Jedl Been here awhile

    Joined:
    Jun 29, 2010
    Oddometer:
    115
    Location:
    New England
    Dave,

    Forgive me for kibitzing but I'm confused by your lack of enthusiasm for the classic "inverted pendulum" example, mostly because I offered the same example in another post. In an inverted pendulum, moving the base of the pendulum out from under the CoG accomplishes a lean two ways: 1) by allowing the offset support and gravity vectors to induce rotation around the base and 2) directly inducing rotation of the pendulum around it's CoG via acceleration of the base in a direction normal to the pendulum's length. For method #2, if we accelerated the base of the pendulum quickly and forcefully enough, the pendulum would "spin" around it's CoG (separating the base from the supporting hand) before gravity could bring the whole shebang tumbling to the ground.

    As we countersteer the front wheel's contact patch "pulls" the bottom of the front wheel sideways along a vector approx. normal to the bike's direction of travel and it's height. The movement of the contact patch is a response to lateral acceleration of that part of the tire that contacts the road surface just like the hand that supports the inverted pendulum. This acceleration then induces roll into the bike via the same two mechanism: 1) by allowing the offset support and gravity vectors to induce rotation around the contact patch and 2) directly inducing rotation of the bike around it's CoG. (OK, the second one is a bit of a stretch since the bike's CoG is not directly over the front contact patch) Are these forces not similar as for the inverted pendulum? I know there are other forces at work in the case of a spinning and turning motorcycle wheel, but are these two forces not similar for the most part?

    You are right that gravity is not the only force at work in this idealized inverted pendulum example or in the inducement of roll of a motorcycle. But the driving force (pardon the pun) is not inertia, but rather acceleration provided through the tires at a point some distance from the CoG, plus acceleration due to offset support and gravitational vectors, plus the torque induced by the changes in the angular momentum vector of the spinning wheel - all of which contribute to rotation around the bike's longitudinal axis.

    Forward movement is not required to induce roll in the "inverted pendulum". The device would react the same way moving at great speed or not moving at all as long as no additional forces were in effect. Forward movement is not required to induce roll in a motorcycle. All we have to do is stop supporting it and it will roll right over until it lays on it's side and hits the ground. Forward movement is required to control the lean of a motorcycle once the CoG becomes displaced relative to the line connecting the contact patches. Once the CoG is displaced laterally from the line of the contact patches, the only way to stop the rotation of the bike is to drive the contact patches to the other side of the CoG - where the rotational momentum of the bike will run squarely into the gravitation forces acting in the opposite direction. Forward movement is also required to counter external forces that would seek to roll the bike - like something impacting the bike from the side or a stiff gust of wind.

    The "seat of the pants" sensations of going around a turn in a car are not inertia "pushing" us outwards but rather acceleration from the tires through the suspension to the frame to the seat "pulling" on our asses into the turn. At any rate, that's how I understand the forces involved. But I'm eager to be educated, if I have things bass-ackwards.

    cheers,

    PS Inertia is not a force but rather a property of matter and physical objects. Inertia is what a force must overcome to induce translational or rotational acceleration on some object or thing.
  3. RGuerra

    RGuerra Adventurer

    Joined:
    Jun 10, 2006
    Oddometer:
    65
    Location:
    Matamoros, Tamaulipas, México
    Countersteering is easely perceived if you ride with only one hand.
    Go ride with only one hand - let's say your right one - and push the handlebar, see what happens. You won't be able to turn left pushing the right side. You will go right. Remember, use only one hand.
    Do the same riding with only your left hand. Push. You will turn left.

    Countersteering will be necessary only to initiate the turn or to increase the rate of turn. Once you have achieved the desired rate of turn, you will 'leave free' the handlebar and it will turn to the correct side you are turning, until you decide to change the rate of turning or end the turn.

    In short, what you do in a turn, known to you or not is:
    Initiate turn by countersteering.
    Reach desired rate of turn.
    Leave hadlebar free, it will reposition itself in accordance with the side and rate of turn.
    Countersteer in one or another direction as necessary to adjust rate of turn... leave handlebar 'free' when rate achieved.
    Finish turn by countersteering -now in the opposite direction of initial countersteer.
    All this, with all the fine tuning necessary, is done in the background by your brain sense of balance.
    But for increased safety in riding, it is very important to to be aware of the existence and necessity of countersteering.

    You can step in one of the footsteps and have a turn to that side, but the rate of turn will be very small compared with countersteering, and smaller as speed increases.

    RG
  4. Klay

    Klay dreaming adventurer

    Joined:
    Nov 19, 2005
    Oddometer:
    103,439
    Location:
    right here on my thermarest

    Yes.
  5. Fajita Dave

    Fajita Dave Been here awhile

    Joined:
    May 13, 2007
    Oddometer:
    717
    Location:
    Barboursville, VA
    I can't think of any reason you would be wrong. Your explanations are much more clear than mine too. The only thing I have a hard time getting my head around with the inverted pendulum is especially when you reach lower lean angles. The CG is so low to the ground the motorcycle doesn't rotate as much around its CG as it is lifting it up off the ground. I'm not arguing that motorcycles don't rotate around the CG, because they do. But there's a lot more going on that just rotating. Maybe I'm just not giving it enough credit for how much it effects the motorcycle compared to other aspects?

    The lean angle of a motorcycle (and rider combined) is the perfect equilibrium of gravity pulling it to the ground and cornering Gs keeping it up right. If you increase the cornering G by turning the front wheel into the corner, than the CG will get "pulled" in the other direction making the bike stand up right. So the CG needs to be forced UP and rotate which inertia can do in this case (from my understanding). There's no doubt its not the only thing going on too so maybe we're just debating the same thing.

    You are right that inertia isn't a force in itself. You most likely know more about physics than I do too and I'd be willing to learn anything. I've actually never taken a physics class in my life so there's no doubt many people know more about it than I do. I just learn through research and talking to others.
  6. Lion BR

    Lion BR I'd rather be riding

    Joined:
    Oct 18, 2005
    Oddometer:
    4,410
    Location:
    Oregon
    You said it and I agree, that's where it seems the issue is on the points you are making.
  7. markk53

    markk53 jack of all trades...

    Joined:
    Dec 20, 2007
    Oddometer:
    9,501
    Location:
    Delaware Ohio
    You cannot see the rider's actions. The leaning and weighting of the pegs is what makes it happen without the bike crashing highside. That is why the steering in the direction works like it does. I have a Bultaco and did that stuff.

    But again as with all countersteering threads, it goes to hell with the science. A hell of a lot of us can walk, but don't have a clue about all the movement and science involved in the action.
  8. markk53

    markk53 jack of all trades...

    Joined:
    Dec 20, 2007
    Oddometer:
    9,501
    Location:
    Delaware Ohio
    Then you should realize what I was saying. Having been around in sales and on the forums,most people who bring up bicycling relating it to motorcycling are most frequently serious cyclists. They relate it to their two wheel experience. Those who just pedal around without thought.will also not relate the experience to that of riding a motorcycle unless asked about it. They don't get the relationship.

    That was what I was saying. They get it.
  9. i_4ce

    i_4ce wants a WeeStrom

    Joined:
    Jul 7, 2005
    Oddometer:
    261
    Location:
    SLC, Utah
    I'd like to see if a person that does not have the concept of counter steering in mind can pass the swerve test. To pass that test I think you have to be fully committed in the belief of counter steering.

    I think the hurt report mentioned riders were crashing into things they were trying to avoid because in a panic situation the riders resorted to a normal steering action causing them to counter steer into the object.
  10. 390beretta

    390beretta Long timer

    Joined:
    Oct 31, 2009
    Oddometer:
    1,221
    Location:
    Phoeniz, AZ
    I honestly can't believe this thread has lived this long.....or that there's been so much "discussion" of this simple damn principle. Anyone who's ridden a bicycle as a kid, or a motorcycle as an adult, should "get it". I will admit that when I started riding motorcycles as a teenager, my "intuitive" sense was "pull the handlebar toward me to turn the opposite direction", and I still do that, although I push and pull, since the whole concept of "countersteering" has come to vogue. But hey, the concept is about as complicated as "the harder you hit a tennis ball, the farther it'll go". Where the hell is all the confusion?
  11. Al Goodwin

    Al Goodwin Long timer

    Joined:
    Nov 16, 2007
    Oddometer:
    1,369
    Location:
    Cullman, Alabama
    AMEN

    Like I said earlier....just a couple of short rides is all it should take.

    For the non-believers out there, watch a motorcycle roadrace sometime, pay close,attention to Amy slow motion of a right/left, or vice-versa, transition. To get from full-lean left to full-lean right quickly takes an aggressive counter-steering input. If I was savy at imbeding video I'd just do that.

    Somebody find one and post it here.....PLEASE.



  12. PSYCHO II

    PSYCHO II Crusty Demon

    Joined:
    May 30, 2011
    Oddometer:
    542
    Location:
    Gold Coast, AUS
    Perhaps you would like to see one when the rider doesn't counter-steer and remains on target fixation.

    <iframe width="560" height="315" src="http://www.youtube.com/embed/AgslHBubWjw" frameborder="0" allowfullscreen></iframe>
  13. Barry

    Barry Just Beastly

    Joined:
    Oct 4, 2002
    Oddometer:
    7,418
    Location:
    Fredericksburg, Va.
    The length of this thread (and similar threads) may be a commentary on just how under developed the skills of the average rider might be...

    Barry
  14. 640 Armageddon

    640 Armageddon -oo-

    Joined:
    Mar 4, 2009
    Oddometer:
    2,860
    Location:
    Greece
  15. Al Goodwin

    Al Goodwin Long timer

    Joined:
    Nov 16, 2007
    Oddometer:
    1,369
    Location:
    Cullman, Alabama
  16. Dolly Sod

    Dolly Sod Red Clay Halo

    Joined:
    Aug 18, 2003
    Oddometer:
    14,071
    Location:
    Richmond, Va
    ...or a commentary on just how long winter is. :evil
  17. Griffin44

    Griffin44 Been here awhile

    Joined:
    Jan 12, 2010
    Oddometer:
    357
    Location:
    Ontario
    True but I'm not sure so many of us would argue with a kinesioligist about the physics of walking. Yet many will argue with well informed and demonstrably well equipped scientists about counter steeering.
  18. pretbek

    pretbek Long timer

    Joined:
    Oct 7, 2008
    Oddometer:
    1,195
    Location:
    SE Pennsylvania
    Should, but many don't.

    Not all riders are aware that they push steer, so in an emergency they will NOT push left to go left.
    They will either push left to go right, or not push at all and try to manage with just body lean like they always managed.
  19. Lion BR

    Lion BR I'd rather be riding

    Joined:
    Oct 18, 2005
    Oddometer:
    4,410
    Location:
    Oregon
    I think this is it!
  20. SteelJM1

    SteelJM1 Undercover KTM rider

    Joined:
    Apr 28, 2007
    Oddometer:
    1,912
    Location:
    Tucson
    My SV is a pretty good demo bike for this. It does the opposite of 'falling into corners' as a proper sportbike should. You have to push it in... and continue pushing to hold the curve, otherwise she'll stand up on her own and quickly. Right hand curve, push on the right clipon. To take it faster/sharper, push harder, and keep it up until the exit.