1Q50.23 Bike Wheel Precession


Precession, angular momentum, torque


When a spinning wheel has a torque applied perpendicular to the axis of rotation, precession occurs.



  • [1] Bicycle wheel with holder
  • [1] Precession post
  • [2] C-clamp
  • [1] Motorized wheel-spinner
  • [1] Extension cord
  • [2] Wooden block (if necessary)

Classroom Assembly

  1. Clamp the precession post to a table with enough clearance so that the wheel won't hit anything while precessing. Use both clamps.
  2. Put the wheel in the holder if it is not already there.
  3. Plug in the wheel-spinner. Use the extension cord for more freedom of movement.

Important Notes

  • Be careful not to get your hands in the wheel spokes when the wheel is spinning.


  1. Spin up the wheel.
  2. Put the eye-bolt on the wheel through the pointy bit at the top of the post.
  3. Watch the wheel precess.
  4. Stop the wheel and put it back on the holder when done.


Additional Resources


  • PIRA 1Q50.23


  • Don't attempt this at home!

Last revised

  • 2017


Related AV

Related demos


If you have any questions about the demos or notes you would like to add to this page, contact Ricky Chu at ricky_chu AT sfu DOT ca.