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ERIC Number: EJ1142562
Record Type: Journal
Publication Date: 2017-Apr
Pages: 2
Abstractor: As Provided
ISSN: ISSN-0031-921X
The Four-Ball Gyro and Motorcycle Countersteering
Galli, J. Ronald; Carroll, Bradley W.
Physics Teacher, v55 n4 p238-239 Apr 2017
Most two-wheel motorcycle riders know that, at highway speeds, if you want to turn left you push on the "left" handlebar and pull on the "right" handlebar. This is called "countersteering." Countersteering is counterintuitive since pushing left and pulling right when the front wheel is not spinning would turn the wheel to the right. All good motorcycle instructors teach countersteering but few understand the physics of why it works, even though there is considerable discussion about it among motorcycle riders. This paper gives a simplified explanation of gyroscopic precession and then applies this to the front wheel of a motorcycle using two steps: (1) explaining how the wheel's lean is initiated, and (2) explaining how the lean will cause the wheel to turn. To assist with this discussion and to demonstrate the conclusions, a "wheel" was constructed using copper pipe, a bicycle wheel hub, and one pound of lead in each of four "balls" at the end of the spokes (see Fig. 1).
American Association of Physics Teachers. One Physics Ellipse, College Park, MD 20740. Tel: 301-209-3300; Fax: 301-209-0845; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Descriptive
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A
Grant or Contract Numbers: N/A