Re: Gyroscopes - Usenet Physics FAQ - Reference frames

From: Gordon (gordonlr_at_DELETEswbell.net)
Date: 08/03/04 

Date: Tue, 03 Aug 2004 18:25:35 GMT

On Tue, 3 Aug 2004 11:55:56 +0100, "JM Albuquerque"
<jm.aREMOV.E@sapo.pt> wrote:

>
>"Myxococcus xanthus" <mold-guardian@comcast.net> wrote:
>>
>> Please do a google search for references to
>> Jones, David E.H., "The Stability of the Bicycle", Physics Today (April
>> 1970): 34-40
>>
>> The gyroscopic contribution to bicycle stability is relatively minor.
>
>Wrong. The gyroscopic action is all that a bicycle needs to be up right.
>Since the bicycle is not accelerating, but travelling at constant speed, no
>force acts upon the bicycle, right ? (except gravity, neglect friction).
>So, why doesn't the bicycle fall under gravity?
>The bigger the bicycle speed is the less the bicycle will trend to fall.
>Is it magic? (since no force acts upon the bicycle at ANY constant speed).
>It is not magic, it is called gyroscopic effect.
>
The gyroscopic action, specifically as pertains to the front
wheel, does play a small part in keeping a bike upright. This
gyroscopic action is more significant at higher speeds. It serves
to steer the center of support such that it remains under the
center of mass, thus maintaining balance.

However, this gyroscopic principle is almost non existent at very
low speeds. Yet it is still possible for the rider to maintain
balance by a combination of shifting his/her weight and also
manually steering, such as to accomplish the same thing that the
gyroscopic principle does at higher speeds.

The mechanical arrangement of the front fork probably plays a
more important roll than any gyroscopic principle, under ordinary
conditions. The caster angle causes the front wheel to steer in
the direction of a developing out of balance tipping. For
example, if the rider starts to tip to the right, the caster
angle's induced response will steer to the right, bringing the
point of support back under the center of mass.

Relevant Pages

  • Re: On low gears
    ... You and your bicycle should roll thirty feet or so. ... With gearing, the same gentle pushing lets practically any bicyclists ... The rider can't trade as much force for distance. ... Minor drags like these be easily ignored at higher speeds, ...
    (rec.bicycles.tech)
  • Re: Gyroscopes - Usenet Physics FAQ - Reference frames
    ... The gyroscopic action is all that a bicycle needs to be up right. ... gyroscopic action is more significant at higher speeds. ... this gyroscopic principle is almost non existent at very ...
    (sci.physics.relativity)
  • Re: Gyroscopes - Usenet Physics FAQ - Reference frames
    ... The gyroscopic action is all that a bicycle needs to be up right. ... gyroscopic action is more significant at higher speeds. ... this gyroscopic principle is almost non existent at very ...
    (sci.physics)
  • Re: Speed record
    ... years ago where the bicycle was displayed. ... mph+ speeds if the bicycle is not being pushed? ... You cited the roller ... Use your own calculator to compare the two speeds. ...
    (rec.bicycles.tech)
  • Re: Speed record
    ... the 138 mph Abbott single-gear bicycle is shown being pedaled ... convertible's windshield at highway speeds. ... you point out they are using motorcycle tyres. ...
    (rec.bicycles.tech)