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Main
Date: 07 Jul 2007 17:10:29
From: Sir Ridesalot
Subject: Cadence @ 40 kph 700C x 34 ring 13 cog
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Hi there.
Iseem to recall that there exists some where info (chart) for
calculating cadences for those of us who do not have a cadence
function on their computers.
I have been taking spinning classes at a local YMCA lately to help
improve my cadence.
The other evening I was tooling along, on a very nice stretch of road,
at 40 kph in my 34 x 13 gear with Schwalbe 700C x 32 mm knobby cyclo-
cross tires. It felt really good and seems to prove that the spinning
classes are helping a lot.
What I was and am wondering is what my cadence was at that speed. Do
any of you know what it was or can you direct me to a site or page
that has a chart of various gear combos and speeds with the cadences?
Thank you very much.
Cheers from Peter
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Date: 09 Jul 2007 01:19:46
From: Bob
Subject: Re: Cadence @ 40 kph 700C x 34 ring 13 cog
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Failing all of the above, you could simply ride the same bike in the
same gear at the same speed and count your pedal strokes or, if you're
really interested in what your cadence is under a variety of
conditions, buy a cyclometer with a cadence function. I'd find either
simpler than charts but I'm mathematically challenged. <g >
Regards,
Bob Hunt
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Date: 08 Jul 2007 23:58:52
From: Tom Keats
Subject: Re: Cadence @ 40 kph 700C x 34 ring 13 cog
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In article <1183962372.386992.171520@x35g2000prf.googlegroups.com >,
carlfogel@comcast.net writes:
> Rounding and whether the tire is 2124 or 2100 mm accounts for the
> slight difference.
Trying to do mathematics on Usenet always ends up
with the simple arithmetic rising to bite my tochis.
So I don't bother to try anymore. The mathematics
might be good, but simple arithmetic on Usenet is
pretty much an invitation to Ol' Harry.
My hat's off ta ya. Unless your arithmetic got
screwed-up too.
Rest assured, I'm not even gonna bother to check.
cheers,
Tom
--
Nothing is safe from me.
I'm really at:
tkeats curlicue vcn dot bc dot ca
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Date: 08 Jul 2007 23:26:12
From:
Subject: Re: Cadence @ 40 kph 700C x 34 ring 13 cog
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On Jul 8, 7:46 pm, RBrickston <rb20170REM...@yahoo.com > wrote:
> In article <t-CdnZNiUprUDQzbnZ2dnUVZ_v6tn...@ptd.net>,
> david.john...@lehigh.edu says...
>
>
>
> > Paul Myron Hobson wrote:
>
> > > 1) Calculate the gear in meters development:
> > > MD = pi/4 * d^2 * GR
> > > d = diameter of the tire*
> > > GR = gear ratio (34/13)
>
> > Um, sorry, but this formula is incorrect. For one thing, pi/4 d^2 is
> > the area of the circle of diameter d, so has no direct relationship to
> > the development. The development is the distance traveled from one
> > revolution of the pedals, MD = pi * d * GR. This is similar to the
> > English/American notion of "gear inches", but (aside from using inches
> > rather than meters), leaves out the pi. That standard came from the
> > days of ordinary bicycles (high-wheelers), where the size of the wheel
> > determined the gear; so in a 70-inch gear you are pedaling the
> > equivalent of a 70-inch tall wheel in a direct-drive ordinary. Anyway,
> > GI = GR * d, a simple ratio.
>
> > > 2) Convert your speed to meters per minute
> > > 40 km/hr * 1000 m/km * 1/60 hr/min
>
> > > 3) Divide your velocity (m/min) by your gear (m/rev),
>
> > This part is correct.
>
> > > *Digging through the source of code of this page:
> > >http://www.sheldonbrown.com/gears/
>
> > That page does have the correct definition of development, although I
> > did not read the source code.
>
> Paging Carl Fogel...
Dear RB,
This calculator . . .
http://www.kreuzotter.de/english/ecadence.htm
. . . predicts 120 rpm for 40 kph = 24.8 mph, 700c
=2124/3.1416(676mm), 34x13.
Oddly enough, so does my sprawling conversion spreadsheet, whose top
secret equation is:
cadence = ( (speed in kmh / 60) / tire circumference in mm) )
*
( 1,000,000 * (rear teeth / front teeth ) )
cadence = ( (40/60) / 2124 )
*
( 1,000,000 * (13/34) )
cadence = 0.0003138 * 382,353
cadence = 119
Rounding and whether the tire is 2124 or 2100 mm accounts for the
slight difference.
Cheers,
Carl Fogel
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Date: 08 Jul 2007 20:04:02
From: Ozark Bicycle
Subject: Re: Cadence @ 40 kph 700C x 34 ring 13 cog
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On Jul 8, 8:46 pm, RBrickston <rb20170REM...@yahoo.com > wrote:
> In article <t-CdnZNiUprUDQzbnZ2dnUVZ_v6tn...@ptd.net>,
> david.john...@lehigh.edu says...
>
>
>
> > Paul Myron Hobson wrote:
>
> > > 1) Calculate the gear in meters development:
> > > MD = pi/4 * d^2 * GR
> > > d = diameter of the tire*
> > > GR = gear ratio (34/13)
>
> > Um, sorry, but this formula is incorrect. For one thing, pi/4 d^2 is
> > the area of the circle of diameter d, so has no direct relationship to
> > the development. The development is the distance traveled from one
> > revolution of the pedals, MD = pi * d * GR. This is similar to the
> > English/American notion of "gear inches", but (aside from using inches
> > rather than meters), leaves out the pi. That standard came from the
> > days of ordinary bicycles (high-wheelers), where the size of the wheel
> > determined the gear; so in a 70-inch gear you are pedaling the
> > equivalent of a 70-inch tall wheel in a direct-drive ordinary. Anyway,
> > GI = GR * d, a simple ratio.
>
> > > 2) Convert your speed to meters per minute
> > > 40 km/hr * 1000 m/km * 1/60 hr/min
>
> > > 3) Divide your velocity (m/min) by your gear (m/rev),
>
> > This part is correct.
>
> > > *Digging through the source of code of this page:
> > >http://www.sheldonbrown.com/gears/
>
> > That page does have the correct definition of development, although I
> > did not read the source code.
>
> Paging Carl Fogel
Having a smarm jones, are ya?
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Date: 09 Jul 2007 03:53:58
From: RBrickston
Subject: Re: Cadence @ 40 kph 700C x 34 ring 13 cog
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In article <1183950242.622629.207850@n60g2000hse.googlegroups.com >,
bicycleatelier@ozarkbicycleservice.com says...
> On Jul 8, 8:46 pm, RBrickston <rb20170REM...@yahoo.com> wrote:
> > In article <t-CdnZNiUprUDQzbnZ2dnUVZ_v6tn...@ptd.net>,
> > david.john...@lehigh.edu says...
> >
> >
> >
> > > Paul Myron Hobson wrote:
> >
> > > > 1) Calculate the gear in meters development:
> > > > MD = pi/4 * d^2 * GR
> > > > d = diameter of the tire*
> > > > GR = gear ratio (34/13)
> >
> > > Um, sorry, but this formula is incorrect. For one thing, pi/4 d^2 is
> > > the area of the circle of diameter d, so has no direct relationship to
> > > the development. The development is the distance traveled from one
> > > revolution of the pedals, MD = pi * d * GR. This is similar to the
> > > English/American notion of "gear inches", but (aside from using inches
> > > rather than meters), leaves out the pi. That standard came from the
> > > days of ordinary bicycles (high-wheelers), where the size of the wheel
> > > determined the gear; so in a 70-inch gear you are pedaling the
> > > equivalent of a 70-inch tall wheel in a direct-drive ordinary. Anyway,
> > > GI = GR * d, a simple ratio.
> >
> > > > 2) Convert your speed to meters per minute
> > > > 40 km/hr * 1000 m/km * 1/60 hr/min
> >
> > > > 3) Divide your velocity (m/min) by your gear (m/rev),
> >
> > > This part is correct.
> >
> > > > *Digging through the source of code of this page:
> > > >http://www.sheldonbrown.com/gears/
> >
> > > That page does have the correct definition of development, although I
> > > did not read the source code.
> >
> > Paging Carl Fogel
>
> Having a smarm jones, are ya?
>
>
Carl's got the calculator links, iirc.
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Date: 07 Jul 2007 21:15:55
From: Paul Myron Hobson
Subject: Re: Cadence @ 40 kph 700C x 34 ring 13 cog
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Sir Ridesalot wrote:
> Hi there.
>
> Iseem to recall that there exists some where info (chart) for
> calculating cadences for those of us who do not have a cadence
> function on their computers.
>
> I have been taking spinning classes at a local YMCA lately to help
> improve my cadence.
>
> The other evening I was tooling along, on a very nice stretch of road,
> at 40 kph in my 34 x 13 gear with Schwalbe 700C x 32 mm knobby cyclo-
> cross tires. It felt really good and seems to prove that the spinning
> classes are helping a lot.
>
> What I was and am wondering is what my cadence was at that speed. Do
> any of you know what it was or can you direct me to a site or page
> that has a chart of various gear combos and speeds with the cadences?
>
> Thank you very much.
>
> Cheers from Peter
>
1) Calculate the gear in meters development:
MD = pi/4 * d^2 * GR
d = diameter of the tire*
GR = gear ratio (34/13)
2) Convert your speed to meters per minute
40 km/hr * 1000 m/km * 1/60 hr/min
3) Divide your velocity (m/min) by your gear (m/rev), Bob's your
father's brother and there you go.
*Digging through the source of code of this page:
http://www.sheldonbrown.com/gears/
I think your wheel diameter is about 27 inches or 0.66 m.
hth,
\\paul
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Date: 08 Jul 2007 21:32:56
From: David L. Johnson
Subject: Re: Cadence @ 40 kph 700C x 34 ring 13 cog
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Paul Myron Hobson wrote:
> 1) Calculate the gear in meters development:
> MD = pi/4 * d^2 * GR
> d = diameter of the tire*
> GR = gear ratio (34/13)
Um, sorry, but this formula is incorrect. For one thing, pi/4 d^2 is
the area of the circle of diameter d, so has no direct relationship to
the development. The development is the distance traveled from one
revolution of the pedals, MD = pi * d * GR. This is similar to the
English/American notion of "gear inches", but (aside from using inches
rather than meters), leaves out the pi. That standard came from the
days of ordinary bicycles (high-wheelers), where the size of the wheel
determined the gear; so in a 70-inch gear you are pedaling the
equivalent of a 70-inch tall wheel in a direct-drive ordinary. Anyway,
GI = GR * d, a simple ratio.
>
> 2) Convert your speed to meters per minute
> 40 km/hr * 1000 m/km * 1/60 hr/min
>
> 3) Divide your velocity (m/min) by your gear (m/rev),
This part is correct.
> *Digging through the source of code of this page:
> http://www.sheldonbrown.com/gears/
That page does have the correct definition of development, although I
did not read the source code.
--
David L. Johnson
What is objectionable, and what is dangerous about extremists is not
that they are extreme, but that they are intolerant.
--Robert F. Kennedy
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Date: 08 Jul 2007 23:54:47
From: Paul Myron Hobson
Subject: Re: Cadence @ 40 kph 700C x 34 ring 13 cog
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David L. Johnson wrote:
> Paul Myron Hobson wrote:
>
>> 1) Calculate the gear in meters development:
>> MD = pi/4 * d^2 * GR
>> d = diameter of the tire*
>> GR = gear ratio (34/13)
>
> Um, sorry, but this formula is incorrect. For one thing, pi/4 d^2 is
> the area of the circle of diameter d, so has no direct relationship to
> the development. The development is the distance traveled from one
> revolution of the pedals, MD = pi * d * GR.
Yeah. pi*d. Sorry. Simple mistake.
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Date: 09 Jul 2007 01:46:06
From: RBrickston
Subject: Re: Cadence @ 40 kph 700C x 34 ring 13 cog
|
In article <t-CdnZNiUprUDQzbnZ2dnUVZ_v6tnZ2d@ptd.net >,
david.johnson@lehigh.edu says...
> Paul Myron Hobson wrote:
>
> > 1) Calculate the gear in meters development:
> > MD = pi/4 * d^2 * GR
> > d = diameter of the tire*
> > GR = gear ratio (34/13)
>
> Um, sorry, but this formula is incorrect. For one thing, pi/4 d^2 is
> the area of the circle of diameter d, so has no direct relationship to
> the development. The development is the distance traveled from one
> revolution of the pedals, MD = pi * d * GR. This is similar to the
> English/American notion of "gear inches", but (aside from using inches
> rather than meters), leaves out the pi. That standard came from the
> days of ordinary bicycles (high-wheelers), where the size of the wheel
> determined the gear; so in a 70-inch gear you are pedaling the
> equivalent of a 70-inch tall wheel in a direct-drive ordinary. Anyway,
> GI = GR * d, a simple ratio.
> >
> > 2) Convert your speed to meters per minute
> > 40 km/hr * 1000 m/km * 1/60 hr/min
> >
> > 3) Divide your velocity (m/min) by your gear (m/rev),
>
> This part is correct.
>
> > *Digging through the source of code of this page:
> > http://www.sheldonbrown.com/gears/
>
> That page does have the correct definition of development, although I
> did not read the source code.
>
>
Paging Carl Fogel...
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