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From: rep@panda.UUCP (Pete Peterson)
Newsgroups: net.cycle
Subject: Re: The Backwards Bike
Message-ID: <1354@panda.UUCP>
Date: Wed, 29-Jan-86 07:57:15 EST
Article-I.D.: panda.1354
Posted: Wed Jan 29 07:57:15 1986
Date-Received: Sat, 1-Feb-86 01:52:10 EST
References: <3007@vax4.fluke.UUCP> <756@athena.UUCP> <63@fai.UUCP> <577@amiga.amiga.UUCP> <687@ttrdc.UUCP>
Reply-To: rep@panda.UUCP (Pete Peterson)
Distribution: net
Organization: GenRad, Inc., Concord, Mass.
Lines: 30
Summary: 

In article <687@ttrdc.UUCP> levy@ttrdc.UUCP (Daniel R. Levy) writes:
>In article <577@amiga.amiga.UUCP>, jimm@amiga.UUCP (Jim Mackraz) writes:
>>I am sure I once read an article on some study being made to determine why
>>bicycles are stable.  They tried everything, including teeny front
>>wheel, backwards bend in the front fork (which was used to _increase_
>>stability in early bicycle speed record runs (+100mph)), counter-rotating
>>dummy front wheel, and so on.  None decreased the stability markedly (they
>>could draw no conclusions on the teeny front wheel idea, since the caster
>>they used would burn up).
>>
>
>Bicycles, motorcycles, unicycles stay up because the rotating wheels are
>in effect gyroscopes.  They resist any attempt to push them directly
>sideways.  I thought this was common knowledge....
>
I read the article mentioned by Jim Mackraz and remember that the authors found
that it was NOT the gyroscope effect that made the bicycle stable.  They
made bicycles with counter-rotating wheels to cancel gyroscopic effects and
found that the bicycles were still quite stable.  The fascinating thing about
that study was that they found it extremely difficult to make a really unstable
bicycle.  My recollection is that the stability on a bicycle/motorcycle resulted
from the fact that tilting the cycle caused the front wheel to turn in a dir-
ection to correct the tilt and right the cycle.  Both bicycles and motorcycles
are quite stable at very slow speeds where one wouldn't expect much gyroscopic
effect.

Unicycles are another matter.  I believe they are kept upright by supernatural
powers of the rider!

	pete peterson