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physics poll: counter-steering

Discussion in 'General' started by Ra.Ge. Raptor, Feb 23, 2020.

?

main reason counter-steering works

This poll will close on Feb 23, 2030 at 3:11 AM.
  1. torque-induced gyroscopic precession

  2. inertia

  3. Neither

Results are only viewable after voting.
  1. G 97

    G 97 Garth

    $2.45 is cheap.:D
     
  2. Ra.Ge. Raptor

    Ra.Ge. Raptor wanna_be_fast

    Inertia might not be 100% correct, but I think it describes the phenomenon quite accurately, at least the initial phase of rolling.

    Think of a trike (2 wheels at the back) turning right. It wants to roll left. Now think of how you initiate the roll of the motorcycle.

    And I quote you:


    Centrifugal? No, it's centripetal :p
     
    Last edited: Feb 24, 2020
  3. Dave K

    Dave K DaveK über alles!

    How exactly is a rainbow made? How exactly does a sun set? How exactly does a posi-trac rear-end on a Plymouth work? It just does.
     
    turner38, brex and R Acree like this.
  4. R Acree

    R Acree Banned

  5. JCW

    JCW Well-Known Member

    Right, and Foale states one does not think about all these actions and consequences while riding a bike (or a motorcycle) once your brain learns them. It all comes becomes natural and the self balancing mechanism of the bike and your inputs compliment each other without thinking.

    I'm just thinking about my kid riding a bike without training wheels for the first time. She took a dump a couple times learning that to turn left to can't just turn the wheel to the left and rely on the training wheels to balance out the forces you create.

    The value part for me comes at the end of the chapter when he applies all the mental masturbation to performance riding and racing and how cog, lighter wheels, rider input etc can affect rate of roll and turning.
     
  6. JCW

    JCW Well-Known Member

    Ahhh, right. o deg of rake, not so much a problem (at least for turning and stabliity, sucks for braking stiction) as long as a "normal" amount of trail is maintained.

    0 trail? you lose one of the self correcting mechanism of the bike and have a rather unstable situation although I have to admit i'll have to read up on it. I'm thinking the wheels of a shopping cart wobbling back and forth uncontrollably.
     
  7. Ra.Ge. Raptor

    Ra.Ge. Raptor wanna_be_fast


    Yeah, I meant to write 0mm of trail, 0° rake.

    Would the front wheel still turn into the direction of the corner when leaned?
     
  8. motoboy

    motoboy Well-Known Member

    Countersteering vs. Vodou shit always reminds me of the Tongue-level vs. Vodou shit constantly argued among trumpet players. But no one actually ever read their John Stuart Mill, so no one will ever learn anything past what they knew was a FACT when they were 7-17 or so, emotionally. Much like the dungeon.
     
  9. Ra.Ge. Raptor

    Ra.Ge. Raptor wanna_be_fast

    Countersteering is the most effective way to add lean angle to a motorcycle. Actually, you can countersteer so hard, that the bike delays its turning!
    I bet you didn’t know that:D
    And you don't always want to add lean angle viciously, trail braking comes to mind.
    Vo-dou shit, huh? :crackup:
     
  10. brex

    brex Well-Known Member

    What is a horse shoe?
    What does a horse shoe do?
    Are there any horse socks?
    Is anybody listening to me?
     
  11. Gino230

    Gino230 Well-Known Member

    If anyone is a non believer in countersteering, you should check out this steam powered rocket used to verify that the earth is flat. I hear it's available cheap.
     
  12. JCW

    JCW Well-Known Member

    So you are talking about the forces around the steering axis...
    According to Foale's simulations, there were 4 forces he followed around the steering axis as the bike was leaned over, gyroscopic, gravitational, tire forces and rider input.
    Assuming a zero trail bike can be leaned, gyroscopic forces and gravitational forces should be present and the bike still should turn want to turn into the lean as the gyroscopic force seemed to be the greatest initially and gravitational increased as lean increased.

    Trail tends to self correct small steering changes when traveling in a straight line but then too much trail also tends to cause wheel flop.

    LOL. I don't know... ask Foale?

    Edit- I wonder if by gravitational forces, he meant the effect of leaning on the forces around the steering axis through trail...
    Still, the gyroscopic forces would be present and strongest initially trying to cause the bars to turn into the corner...
     
    Ra.Ge. Raptor likes this.
  13. Ra.Ge. Raptor

    Ra.Ge. Raptor wanna_be_fast

    I'm just exploring the physics behind countersteering, I'm not questioning its usefulness.
     
    Gino230 likes this.
  14. chickenpants

    chickenpants Well-Known Member

    here’s your corn planter
     

    Attached Files:

    Sabre699 likes this.
  15. gixxernaut

    gixxernaut Hold my beer & watch this

    An hypothesis about how counter-steering works isn't complete until it accounts for all the evidence.

    3-wheel-child-kick-scooter-small-wheel.jpg

    This little bastard counter-steers just as effectively as a bicycle or motorcycle rolling down the road at normal highway speeds. It does it whether there's 40 pound kid on it or if there's a 250 pound ape like me. It counter-steers effectively even at speeds of 5-10 miles per hour. It does this in spite of the very negligible amount of gyroscopic force generated by these tiny wheels.

    I certainly respect the amount of gyroscopic force that can be generated by a motorcycle wheel doing upwards of 80 MPH, but it seems to me like balancing a motorcycle is very much like balancing a broom on your hand. If you want to move right you move the base of the broom a little to the left so the top starts falling towards the right. Then if you're skilled enough you can track with the bottom and keep it from falling over until you've "picked it back up" by centering the base of the broom under the top. By then the whole assembly (your palm and the broom) has been moved towards the right.

    When you're standing on this kick scooter it is the "palm" and you are the "broom." When you turn the front wheel, the bottom begins moving in the direction it was turned, causing you to start falling in the opposite direction. Then you turn the wheel into the turn to strike a balance between centrifugal force (inertia) and gravity until you're done turning. Then you pick the bike up by reversing the order of operations. Turn the wheel slightly more into the direction you're leaning until the bottom catches up with the top and the whole thing is upright again.

    Because of this I think "inertia" plays a much more significant role in counter-steering than gyroscopic effect, even on much larger vehicles and at higher speeds.
     
    JCW and Ra.Ge. Raptor like this.
  16. pickled egg

    pickled egg Tell me more

    It would fall off the treadmill.
     
  17. JCW

    JCW Well-Known Member

    That broom is an excellent example and provides another "visual" representation of the gravitational and the lateral tire (or palm) forces involved.
    In physics, this is called an inverted pendulum.

    If I could add one thing...

    It is much easier getting a bike to negotiate a corner than actually balancing a broom leaning in one direction while moving it in that direction.
    And that is because of the multitude of forces present to self correct the bike. One of those forces available is gyroscopic precession around the steering axis as the spinning wheels are banked into a corner.

    So while, yes, gyroscopic forces are not necessary to lean the bike through countersteer, it plays a vital role in the stability of a bike that makes them self balancing and thus easier to ride.
     
  18. tophyr

    tophyr Grid Filler

    the GOD DAMN AIRPLANE TAKES OFF TWICE AS FAST AS ONE ON A STATIONARY BICYCLE
     
  19. blkduc

    blkduc no time for jibba jabba

    The really smart guy on the video explained it, "brake...then throttle...then turn in".

    :moon:
     
    crazymofo likes this.

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