Cadence @ 40 kph 700C x 34 ring 13 cog

[Sir Ridesalot]

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

 

[Paul Myron Hobson]

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

 

[David L. Johnson]

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

 

[RBrickston]

In article <[email protected]>,
[email protected] 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...

 

[Ozark Bicycle]

On Jul 8, 8:46 pm, RBrickston <[email protected]> wrote:
> In article <[email protected]>,
> [email protected] 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?

 

[RBrickston]

In article <[email protected]>,
[email protected] says...
> On Jul 8, 8:46 pm, RBrickston <[email protected]> wrote:
> > In article <[email protected]>,
> > [email protected] 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.

 

[Paul Myron Hobson]

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.

 

[[email protected]]

On Jul 8, 7:46 pm, RBrickston <[email protected]> wrote:
> In article <[email protected]>,
> [email protected] 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

 

[Tom Keats]

In article <[email protected]>,
[email protected] 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

 

[Bob]

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