Center of gravity

In what general area is the center of gravity for a standard, diamond shaped frame bicycle with and
without a rider? Also, is the cg off the centerline due to the extra equipment (fr/rear der,
chainrings, cassette, chain) on the right side?

Greg Hall

 

Greg Hall wrote:

> In what general area is the center of gravity for a standard, diamond shaped frame bicycle with
> and without a rider?

Bike CG falls on a line near or slightly in front of the bottom bracket. I don't know how high off
the ground, though. Why don't you measure it on your bike and let us know?

Human CG is about at the navel. In a riding position, CG would move in front of the navel.

> Also, is the cg off the centerline due to the extra equipment (fr/rear der, chainrings, cassette,
> chain) on the right side?

Probably slightly, but what does it matter? This is also easy to measure.
--
terry morse Palo Alto, CA http://www.terrymorse.com/bike/

 

My non technical estimate: The CG of a bicycle, a bit dependant on how the rider sits, is either
chest or shoulder to top of bars. The weight of the bicycle itself is not that significant. I'd
venture a guess that keeping your change and wallet in your left pocket will offset the differences
of the sides on the bicycle. Touring with paniers and low riders racks will lower the cg.

Many years ago I was told motorcycles are safer that scooters. Supposedly, the MC chainline is CG
and for scooter between navel and top of bars.

On 13 Feb 2003 06:35:15 -0800, [email protected] (Greg Hall) wrote:

>In what general area is the center of gravity for a standard, diamond shaped frame bicycle with and
>without a rider? Also, is the cg off the centerline due to the extra equipment (fr/rear der,
>chainrings, cassette, chain) on the right side?
>
>Greg Hall

 

"Greg Hall" <[email protected]> wrote in message
news:[email protected]...
> In what general area is the center of gravity for a standard, diamond shaped frame bicycle with
> and without a rider? Also, is the cg off the centerline due to the extra equipment (fr/rear der,
> chainrings, cassette, chain) on the right side?

It's usually somewhere just above and in front of the front changer but htat varies by frame size
and equipment. The right-left bias is miniscule

OK I'll bite. Why?

--
Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971

 

"A Muzi" <[email protected]> wrote in message news:<[email protected]>...
> OK I'll bite. Why?

No particular reason other than curiosity. I was watching an episode of the 'Build your own plane'
program on the Wings channel and determining the location of the cg was a step in getting
certification. Made me wonder about a bike's cg.

Thanks for the responses.

Greg Hall

 

Most bike/rider cg combinations are in the region of the belly button. More important on a bicycle
is how much weight is on each wheel as it normally would be ridden. Front to rear weight balance.
This knowledge is useful for loaded touring or racing. Helps in predicting how a bike might handle.
Sounds crazy I know, but I have a notebook with the weight balance of every bike I've owned for the
past 20 years. Mostly recumbents but some uprights too. 5% change can have some dramatic effects. I
think it is knowledge like this that helps me win races. Just won another one last sunday. Happy
cycling Steve "Speedy" Delaire

Greg Hall wrote:

> In what general area is the center of gravity for a standard, diamond shaped frame bicycle with
> and without a rider? Also, is the cg off the centerline due to the extra equipment (fr/rear der,
> chainrings, cassette, chain) on the right side?
>
> Greg Hall

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As with any rigid object, you can hang it from any point and the cg falls straight below it. So if
you do this twice, you'll find the cg of your bike. Good luck doing it with people.

"S. Delaire \"Rotatorrecumbent\"" <[email protected]> wrote in message
news:<[email protected]>...
> Most bike/rider cg combinations are in the region of the belly button. More important on a bicycle
> is how much weight is on each wheel as it normally would be ridden. Front to rear weight balance.
> This knowledge is useful for loaded touring or racing. Helps in predicting how a bike might
> handle. Sounds crazy I know, but I have a notebook with the weight balance of every bike I've
> owned for the past 20 years. Mostly recumbents but some uprights too. 5% change can have some
> dramatic effects. I think it is knowledge like this that helps me win races. Just won another one
> last sunday. Happy cycling Steve "Speedy" Delaire
>
>
>
>
> Greg Hall wrote:
>
> > In what general area is the center of gravity for a standard, diamond shaped frame bicycle with
> > and without a rider? Also, is the cg off the centerline due to the extra equipment (fr/rear der,
> > chainrings, cassette, chain) on the right side?
> >
> > Greg Hall
>
>
>
> -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1
> Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =-----

 

> > Greg Hall wrote: In what general area is the center of gravity for a standard, diamond shaped
> > frame bicycle with and without a rider? Also, is the cg off the centerline due to the extra
> > equipment (fr/rear der, chainrings, cassette, chain) on the right side?

"S. Delaire "Rotatorrecumbent"" <[email protected]> wrote in message
news:[email protected]...
> Most bike/rider cg combinations are in the region of the belly button. More important on a bicycle
> is how much weight is on each wheel as it normally would be ridden. Front to rear weight balance.
> This knowledge is useful for loaded touring or racing. Helps in predicting how a bike might
> handle. Sounds crazy I know, but I have a notebook with the weight balance of every bike I've
> owned for the past 20 years. Mostly recumbents but some uprights too. 5% change can have some
> dramatic effects. I think it is knowledge like this that helps me win races. Just won another one
> last sunday.

I am not arguing with you , just wondering how you use the knowledge of where your bike/rider CG is
to effect any improvement.

Location of CG- Interesting? Sure! Faster?? How?

--
Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971

 

With a recumbent the cg is lower then an upright which helps with corning speed. Many can corner at
higher speeds due to the fact that pedals never strike the ground. What this means is the tires are
under higher loads then what they were design for. Idea situation is to have 50/50 weight
distribution. Not always possible. So if one end is lighter then the other the rider can plan on,
and be aware of, which end will break loose first. And/or have the knowledge to rebalance the load
some how. Winning takes preparation. Happy cycling Speedy

A Muzi wrote:

> > > Greg Hall wrote: In what general area is the center of gravity for a standard, diamond shaped
> > > frame bicycle with and without a rider? Also, is the cg off the centerline due to the extra
> > > equipment (fr/rear der, chainrings, cassette, chain) on the right side?
>
> "S. Delaire "Rotatorrecumbent"" <[email protected]> wrote in message
> news:[email protected]...
> > Most bike/rider cg combinations are in the region of the belly button. More important on a
> > bicycle is how much weight is on each wheel as it normally would be ridden. Front to rear weight
> > balance. This knowledge is useful for loaded touring or racing. Helps in predicting how a bike
> > might handle. Sounds crazy I know, but I have a notebook with the weight balance of every bike
> > I've owned for the past 20 years. Mostly recumbents but some uprights too. 5% change can have
> > some dramatic effects. I think it is knowledge like this that helps me win races. Just won
> > another one last sunday.
>
> I am not arguing with you , just wondering how you use the knowledge of where your bike/rider CG
> is to effect any improvement.
>
> Location of CG- Interesting? Sure! Faster?? How?
>
> --
> Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971

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Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =-----

 

Been there, done that. I duct taped myself to the bike, hung the bike from 3 different locations in
front of a blank wall and had someone draw my profile on the wall. Some good lessons from that one.
Happy cycling Speedy

mixedkid wrote:

> As with any rigid object, you can hang it from any point and the cg falls straight below it. So if
> you do this twice, you'll find the cg of your bike. Good luck doing it with people.
>
> "S. Delaire \"Rotatorrecumbent\"" <[email protected]> wrote in message
> news:<[email protected]>...
> > Most bike/rider cg combinations are in the region of the belly button. More important on a
> > bicycle is how much weight is on each wheel as it normally would be ridden. Front to rear weight
> > balance. This knowledge is useful for loaded touring or racing. Helps in predicting how a bike
> > might handle. Sounds crazy I know, but I have a notebook with the weight balance of every bike
> > I've owned for the past 20 years. Mostly recumbents but some uprights too. 5% change can have
> > some dramatic effects. I think it is knowledge like this that helps me win races. Just won
> > another one last sunday. Happy cycling Steve "Speedy" Delaire
> >
> >
> >
> >
> > Greg Hall wrote:
> >
> > > In what general area is the center of gravity for a standard, diamond shaped frame bicycle
> > > with and without a rider? Also, is the cg off the centerline due to the extra equipment
> > > (fr/rear der, chainrings, cassette, chain) on the right side?
> > >
> > > Greg Hall
> >
> >
> >
> > -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1
> > Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =-----

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Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =-----

 

S? Delaire writes:

> With a recumbent the CG is lower then an upright which helps with corning speed.

Oh! Explain what CG height has to do with cornering on a single track vehicle. I think you will
notice that tall people corner as fast as short ones. When in doubt, see picture of bicycle
cornering faster than any recumbent I have met:

http://www-math.science.unitn.it/Bike/Countries/Europe/Tour_Reports/Tour_of_the_Alps_Gallery/ti-
retest.jpg

> Many can corner at higher speeds due to the fact that pedals never strike the ground. What this
> means is the tires are under higher loads then what they were design for.

That you repeat this myth and lore makes obvious that you haven't done this. Imbalance of pedaling
at maximum lean angles causes break-out (crash). That is why bicycle pedals are only high enough off
the ground to allow pedaling up to the practical limit. If it were beneficial, pedals would be
higher off the road.

> Idea situation is to have 50/50 weight distribution. Not always possible. So if one end is lighter
> then the other the rider can plan on, and be aware of, which end will break loose first. And/or
> have the knowledge to rebalance the load some how. Winning takes preparation.

How about some explanation why state these as axioms of bicycling. There ought to be some reasonable
and compelling reason for your opinion to make it credible.

Jobst Brandt [email protected] Palo Alto CA