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counter-steering -- oops!



Oops, I made a rather silly mistake in my recent post about
counter-steering. That's the problem with back of the envelope
calculations: I can never find the envelope's handy reference section.

In "moment of inertia has dimensions of mass times radius squared", I for
got the "squared" part. Luckily for me, correcting the error strengthens
my argument.

After arriving at the relation between bicycle lean (phi) and front wheel
turn (alpha), it should go like this:

phi = [0.5 L/I] alpha t
For a 1 kg, 0.33 m radius wheel going 5 m/s, L = 1.67 kg m^2/s.
For a 65 kg person on a 10 kg bike about 1 m off the groung, I~= 70 kg m^2.
Thus phi = alpha t/(83 sec).

You still get that the lean is very small relative to the wheel turn.

--
--James McLean
jmclean@chem.ucsd.edu
post doc
UCSD