21 ms·

What you unconsciously do when turning, is to quickly turn it a bit in the other direction first in order to get the bicycle more to the other side of you, so y

• Adirael 9y ago
  That's countersteering [1]. I find it very hard to explain but it's something that most people on a bicycle (at speed) or a motorcycle (again, at speed) do naturally. [1] https://en.wikipedia.org/wiki/Countersteering https://en.wikipedia.org/wiki/Countersteering
  • Moodles 9y ago
    I'm no physicist, but it seems the intuitive reason countersteering works is because when you turn, e.g. left, your center of mass also moves left because you need to lean left in order to turn. So if you turn left on your own this will move your center of mass left. And if you turn too sharply left your center of mass will be so far out that you will fall over. So turning right very quickly before turning left means that your center of mass suddenly shifts massively right, and therefore you get some extra time turning left while your center of mass is still busy shifting from right to left?
  • NLips 9y ago
    I'd like to especially highlight your 'at speed' point here. It's often claimed that _all_ steering on a bike requires countersteering, but that is false. Countersteering allows rapid change of direction, but if you're going in a straight line, then lean left and gently steer left (or just lean left and allowing the front wheel to steer itself), you _will_ go left, no countersteering required.
    • ozim 9y ago
      If you lean left, front wheel will "do" countersteering itself (same as noted). Since gyroscopic effect on bike is not so big and speed, mass is not bigger than rider it is not noticable. For motorbike you cannot just lean hence need for explicit countersteering because of much higher forces involved. So I think it is correct to say that countersteering is always required.
      • baud147258 9y ago
        > countersteering is always required Only on a motorbike.
        • marodox 9y ago
          > If you lean left, front wheel will "do" countersteering itself The same applies to a bicycle.
        • ioseph 9y ago
          > Only on a motorbike. Only above a certain speed, at low speeds countersteering will not work Similarly above a certain speed on a bicycle countersteering is the only way you can turn
          • schoen 9y ago
            Some people seem to describe this difference as unconscious countersteering versus deliberate countersteering, that is, that the difference isn't really whether you're countersteering or not, but whether the countersteer is large enough that you have to do it "on purpose".
        • jstanley 9y ago
          The steering geometry is exactly the same. The only time you steer left to go left is if you're going so slowly that the only reason the bike doesn't fall over is because of your near-superhuman balance. That is to say, when you're practically at a standstill. Anywhere approaching walking pace or above, if you try to turn left by steering left, you'll fall off the right hand side before you make any appreciable turn.
  • baud147258 9y ago
    On a bike, even at speed you can initiate a turn by simply leaning on the side.
    • marodox 9y ago
      The front wheel still kicks out in the opposite direction and counter steers for you due to the natural stabilizing properties of the bike
    • rplnt 9y ago
      Easiest way to try/prove this is ride without holding handlebars. You can turn corners easily. Limits (compared to regular turning) are your lowest speed is higher (where you'd lose balance without holding handlebars) and the fact your center of gravity and stability are messed up (can't turn as tightly). And self preservation of course.
      • baud147258 9y ago
        I've done a lot of riding without holding handlebars, so that's how I learned this. Another limits is that you've got a delay to reach the brakes, which can make it dangerous for others in addition to yourself. And I agree that having your center of gravity moved up really mess up your stability.
        • maskros 9y ago
          Only if you've got a stupid racing bike with only hand brakes. Coaster/foot/back-pedal brakes are standard issue around these parts, and I wouldn't ever want to ride a bike without one.
          • JoeAltmaier 9y ago
            Depends on how you ride. An adult in the US, you're on a road bike bent over the bars and going 15-20mph. Hands on the brakes at all times. I do a ride every summer with 20,000 like-minded people and if you see even one bike with coaster brakes all week its unusual.
  • rplnt 9y ago
    It's very easy to try. Go up to speed (20 km/h or so) and press on a handlebar, away from you. You will "turn" to that side even though the handlebars are moving in the opposite direction.
  • dahart 9y ago
    Counter steer happens at all speeds at all times on a two-wheel vehicle, it's just hard to notice at slow speeds, and confusing because you do steer right during the stable lean angle portion of a right turn, as depicted in the first image in that Wikipedia article. I think counter-steering is misunderstood since people assume it means that if you're turning right then your steering has to be left of center. But counter-steering is referring to the direction of change, the steering delta, not the absolute steering angle. You always steer in the opposite relative direction from what you'd do in a car. This is still true on a bicycle at 1mph.
  • arnarbi 9y ago
    Here's how I explained countersteering to myself: To turn left, I need to lean left. The easiest way to lean left is to pull the bottom of the bike, where the wheels touch the ground, to the right.
  • upofadown 9y ago
    Not fan of the term "countersteering". If you changed the mechanical direction that the handlebars rotated the front wheel I doubt anyone would bother to call it "prosteering". A better way to think about this is that bikes turn by banking. The method of controlling the angle of bank does not map in a simple way to the direction of turn.
    • NegativeLatency 9y ago
      Do you have a better single word or short phrase to describe it though?
      • upofadown 9y ago
        Well the aviation people, who also control vehicles that are controlled by banking, don't bother to come up with a special name. When teaching people to fly they first teach how the controls can be used to control the attitude of the vehicle (roll, pitch, yaw are the terms that are used). Then they start a whole new discussion of how various attitudes will affect where the vehicle will end up. Some things can't really be simplified (and perhaps shouldn't be).
    • dahart 9y ago
      > The method of controlling the angle of bank does not map in a simple way to the direction of turn. Sure it does! (Unless by "simple" you're ruling out derivatives). If your wheel angle is moving right, then your bank angle is increasing left (or IOW, your left turn is becoming sharper, left turn radius is decreasing). While your wheel angle is moving left, your bank angle is increasing right. Whenever you stop moving the wheel, your bank angle will stop changing and you will be in a constant radius turn. > I doubt anyone would bother to call it "prosteering". Not sure I understand this objection... there's no rule about symmetric or consistent prefixes. Lots of things called X have a counter-X (see also anti-X). Examples: counter-intuitive, counter-insurgency, counter-strike, counter-reformation, counter-current, etc. Counter-steering is differentiating from steering. But there's no need to differentiate normal steering from steering, so we don't normally prefix things with "pro", unless you're talking about someone who advocates for something. I think there are a few counter-examples to that in physics though. :) In motorcycle safety, it's rather important to call out the counter-intuitiveness of counter-steering. People's reflexes tend to do the wrong thing in tight situations where quick steering is needed. If you need to turn right very quickly and haven't learned counter-steering, you can injure yourself by trying to steer right, and many people have. It's pretty common for riders who haven't learned counter-steering to believe that leaning hard will be sufficient, and/or that body lean is as or more important than steering. But to turn very quickly, knowing about and being able to counter-steer is incredibly important.
  • skookumchuck 9y ago
    I used to ride a bike with no hands. I was still able to countersteer! If I leaned to the left, the bike would lean to the right, the steering wheel would go right, then I could lean to the right into the turn.
  • lisper 9y ago
    The best way I've found to experience this is to first learn to ride with no hands. This works best at speed. You actually steer by shifting your weight, but the easiest way to learn is is to grip the seat with your thighs and think about turning the bike by trying to turn the seat. Once you can stabilize a no-hands ride, try pushing on the handlebar with one finger. You will find the the bike turns in the opposite direction of what you would naively expect. The harder you push, the tighter the turn will be in the "wrong" direction.
• lmm 9y ago
  > Try following a straight marker on the road on your bike. It's very hard. When you start going too much to the right, you will find it impossible to actually nudge the bike back to the left, unless you accept that you have to go further to the right first. Not true - you just have to shift your weight to the left.
  • fwdpropaganda 9y ago
    > Not true - you just have to shift your weight to the left. Not true - because of conservation of momentum (in the perpendicular direction) if you shift you weight to the left the bicycle will lean to the right and the center of mass will remain unchanged. It's called countersteering, look it up.
    • marodox 9y ago
      I never thought I'd see people arguing against counter steering on HN, I left that up to youtube comments.
      • fwdpropaganda 9y ago
        On the contrary, it doesn't surprise me at all. Many people on HN are young and successful which often means they overestimate how confident they should be in subjects outside their area of expertise. It's not just simple mechanics either, it's everything. Didn't you see just yesterday that lunatic claiming that the "4-color map theory is bunk"? https://news.ycombinator.com/item?id=16862553 https://news.ycombinator.com/item?id=16862553
    • lmm 9y ago
      You look it up. Every article you'll find will point out that on a light vehicle like an bicycle you don't need to countersteer with the handlebars and can achieve the same effect by weight shifting. (Indeed the fact that it's possible to ride a bicycle without holding the handlebars at all should be all the proof that's necessary that one can navigate through weight shifting alone).
• trzmiel4 9y ago
  The explanation is that you need to balance out centrifugal force F=mv^2/r. "Sharp turn" has smaller radius, therefore much larger the force. By turning in the opposite direction first, you're making the turn much less sharp, increasing the radius and thus reducing the force.
• eezurr 9y ago
  I've wondered if following a painted line on a road with your bike is an example of Zen. The more I try to follow the line, the harder it is to stay on it. But when I stop trying/thinking about it, I have no problem staying on that line.
  • komali2 9y ago
    And if you don't take a moment to occasionally look up from the line to consider your surroundings, you might crash into an Uber.
    • Froyoh 9y ago
      Or a car
• tzs 9y ago
  > But try this: Try following a straight marker on the road on your bike. It's very hard. When you start going too much to the right, you will find it impossible to actually nudge the bike back to the left, unless you accept that you have to go further to the right first. This holds in general for any motion where velocity is a continuous function of time, doesn't it? Let f(t) be your deviation at time t perpendicular to the desired straight path, with positive to the right and negative to the left. If you are "going too much to the right" at time t, e.g., f'(t) > 0, then because f' is continuous there must be some interval around t such that f' > 0 at all points in the interval. That means that f is strictly increasing throughout that interval, e.g., "you have to go further to the right first".
• russdill 9y ago
  I've always thought of it like a plane, with the terms adverse yaw and adverse roll applying. The main difference is if your turn is uncoordinated, you fall over. Yaw is controlled via the handlebars. Roll is controlled via balance. Just turning the handlebars causes adverse roll in the other direction. If you are falling to the left, turning the wheel to the right causes an opposite roll and restores balance. Turning the handlebars the opposite way momentarily is a great way to start a turn because of the adverse roll that it causes.