Why is it easier to balance a bike while moving faster
Answers
Answer:
Explanation:
A non-moving bike has wheels that aren't spinning and zero angular momentum, which makes it very easy for external torque to change the wheels' direction, making the bike harder to balance. Even when staying relatively motionless, though, a rider can balance a bike with some effort.
It’s because of the way counter-steering is used to steer and balance a bicycle. A lot of people have the wrong intuition about this, but you can quite easily prove to yourself that this is how it works.
Try to ride a bicycle as slowly as you possibly can. As you’ve noticed, the slower you go, the more it develops a tendency to fall over to one side or the other. Pay close attention to what you do to correct it when this happens: when it begins to tilt to the left, you turn the steering to the left. When it falls to the right, you turn the steering to the right. Why does this work?
An easy way to understand it is that if you are upright, travelling in a straight line, and you turn the bars to either side, you are pulling the front wheel out from under the bike in the direction in which you turned the bars. Inertia prevents it from bringing the rest of the bike and rider with it, so this has the effect of leaning the bike left if you turned the bars right, and right if you turned the bars left. When the bike is in a leaning position (while turning a corner or when it has just started to fall to one side while riding slowly), you can turn the bars in the direction of the lean to effectively push the front wheel across, back under the centre of gravity, and bring it upright again.
It surprises me how many people ride around on bicycles competently without realising that this is what they’re doing to negotiate corners. Somehow (maybe because they learned by practising it rather than thinking about it) their intuition is often that they turn right by turning the bars to the right, and left by turning them to the left, but that’s exactly backwards for a vehicle with this wheel configuration. This is incredibly obvious when you ride a motorcycle at speed, but it applies just as much to bicycles and even tiny kick-scooters.
Imagine you are moving forwards and the bike begins to fall to the right. Turning the bars to the right doesn’t in itself make the front wheel move to the right (back under the centre of gravity); it just angles the wheel such that rolling it forwards will now move it to the right. For that reason, it will move more quickly in the direction you steered it for a given steering angle if you are moving forwards faster. Put differently, if you are moving more slowly, correcting for a lean by counter steering in a given amount of time takes a larger steering input.
This is why bicycles feel less stable at lower speeds, and it’s why a bicycle at rest is very unstable. At rest, there is no forward motion and the steering corrections cannot correct for the lean at all as it begins to fall. The main control you have over the balance of the bicycle is less effective at low speeds, and completely ineffective when stopped.