Physics of riding a motorcycle

  • Context: High School 
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    Motorcycle Physics
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Discussion Overview

The discussion revolves around the physics of motorcycle steering, specifically the technique known as countersteering, which is used to turn a motorcycle at high speeds. Participants explore the mechanics behind this method and its similarities to bicycle steering.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants explain that countersteering involves pushing on the handlebar in the direction opposite to the desired turn, which initially seems counterintuitive.
  • One participant describes the process of leaning into a turn, stating that to turn left, a rider must briefly steer right to initiate the lean.
  • Another participant emphasizes the importance of practical experience in understanding countersteering, suggesting that the physical act of pushing on the handlebars creates a quick change in direction.
  • It is noted that the steering geometry of motorcycles is designed to facilitate this leaning process, with some bikes having different responses based on their design.
  • Participants mention that similar principles apply to bicycles, indicating that countersteering is not exclusive to motorcycles.

Areas of Agreement / Disagreement

There is no consensus on the best way to explain or understand countersteering, as participants express varying levels of familiarity and experience with the concept. Some find it intuitive after practice, while others highlight its counterintuitive nature.

Contextual Notes

Participants reference previous discussions on countersteering and bodysteering, indicating that there may be additional nuances or models related to motorcycle steering that are not fully explored in this thread.

Who May Find This Useful

This discussion may be useful for motorcycle riders, enthusiasts, and those interested in the physics of motion and steering dynamics.

thomasxc
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my father recently took a motorcycle class he had to take in order to be able to legally ride one. he said we was told that, in order to turn at high speed, he was supposed to push on the side of the handlebar that he wanted to go. as in, he had to push with his left hand and pull with his right in order to turn left. if this is correct, i don't understand the physics in it. does anyone else know?? thanks.
 
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thomasxc said:
my father recently took a motorcycle class he had to take in order to be able to legally ride one. he said we was told that, in order to turn at high speed, he was supposed to push on the side of the handlebar that he wanted to go. as in, he had to push with his left hand and pull with his right in order to turn left. if this is correct, i don't understand the physics in it. does anyone else know?? thanks.

It's called "countersteering", and is one way of steering a motorcycle. We've had discussions about countersteering and "bodysteering" (a different way to steer) here on the PF before... I'll see if I can find them with a search...
 
Short version: In order to turn left, you have to lean left; to lean left, you have to steer right briefly (so that tires are steered right from under you, leaning the bike left); once leaned, you steer left, ... and vice versa.

The steering geometry of most motorcycles is designed to steer excessively inwards based on the lean angle (and reasonable speeds), which cause the motorcyle to return or remain vertical without steering inputs. Once leaned, the excessive inwards steering requires a bit of outwards steering torque applied to the handlebars is needed to hold a lean angle on most motorcycles. Braking while leaned can increase the excessive inwards steering response. Some racer-replica sport bikes are designed to minimize the excessive inwards response, but are a bit less stable.
 
thomasxc said:
my father ... said we was told that, in order to turn at high speed, he was supposed to push on the side of the handlebar that he wanted to go.

Well I hope they did more than "tell" him this. As in, I hope the class included an opportunity to do it. No argument or physics-based explanation can substitute for the almost magically 'quick' change in direction induced by actually pushing on the bars at speed. Countersteering flat works. And the more you do it, the more natural it seems.
 
he did say it worked. and i think its interesting simply because it seems counter-intuitive. then again, so are a lot of physics phenomena.
 
exact opposite of driving a snow mobile
Canadians..help me here!
 
This works on bicycles as well. Hi speed is not necessary. Just apply a gentle pressure and get ready to lean and turn.
 
the second thread is a good one, berkeman.thx.
 
  • #10
and i am on my way outside to try that, integral. hah.
 
  • #11
i jumped on the bicycle. it totally works, and that's totally awesome! (forgive my 17 year-old, lacking vocabulary.)
 

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