Gear times cadence = speed?

Hell and High Water said:

If I'm on my trainer, and I know what gear I'm in, and what my cadence
is, how would I calculate what speed I would be travelling on the road?

TIA,

-Bob

One way would be to check speed while you are riding on the road at a
certain gear and cadence. For example, I have been forcing myself to
ride in smaller gears for the past ten days, and I know that if I'm in
my 53 x 19, going 28 kph, I'm pedaling just over 80 rpm. At 31 kph, I'm
right around 90 rpm. I admit I haven't tried really hard to get totally
accurate numbers.

So, on the trainer, you could take the cadence and gear combo, and
"solve" for speed, based on what you learned on the road.

You could also work it out with pencil and paper.
Get your wheel diameter (you usually set your bike computer to the
diameter in millimeters, something on the order of 2093 if you ride on
23 mm tires - check it for accuracy!),

get your gear ratio (39 x 19 is 2.05 revs of the wheel for every rev of
the pedals),

multiply these two numbers to get the distance traveled in one pedal
revolution at that gear ratio (2093 mm x 2.05 = 4290.65 mm),

multiply that by your rpm (4290.65 x 80 = 343252 mm / minute),

multiply that by 60 minutes (20595120 mm), and

divide by 1,000,000 to convert to kilometers / hour (20.6 kph, or about
13 mph).

You can make a spreadsheet that covers the ratios for all of your gear
combinations and several cadence values, and paste it on the wall next
to your trainer.

Or, you could move to California, where you don't need no stinkin' trainer!

In article <[email hidden]>,
[email hidden] says...

Quoted message said:

Hell and High Water said:

If I'm on my trainer, and I know what gear I'm in, and what my cadence
is, how would I calculate what speed I would be travelling on the road?

TIA,

-Bob

One way would be to check speed while you are riding on the road at a
certain gear and cadence. For example, I have been forcing myself to
ride in smaller gears for the past ten days, and I know that if I'm in
my 53 x 19, going 28 kph, I'm pedaling just over 80 rpm. At 31 kph, I'm
right around 90 rpm. I admit I haven't tried really hard to get totally
accurate numbers.

So, on the trainer, you could take the cadence and gear combo, and
"solve" for speed, based on what you learned on the road.

You could also work it out with pencil and paper.
Get your wheel diameter (you usually set your bike computer to the
diameter in millimeters, something on the order of 2093 if you ride on
23 mm tires - check it for accuracy!),

get your gear ratio (39 x 19 is 2.05 revs of the wheel for every rev of
the pedals),

multiply these two numbers to get the distance traveled in one pedal
revolution at that gear ratio (2093 mm x 2.05 = 4290.65 mm),

multiply that by your rpm (4290.65 x 80 = 343252 mm / minute),

multiply that by 60 minutes (20595120 mm), and

divide by 1,000,000 to convert to kilometers / hour (20.6 kph, or about
13 mph).

You can make a spreadsheet that covers the ratios for all of your gear
combinations and several cadence values, and paste it on the wall next
to your trainer.

Or, you could move to California, where you don't need no stinkin' trainer!

OUTSTANDING!!!

La Jolla? or Orinda?

Thanks so much!

-Bob

On Oct 10, 10:27 am, Hell and High Water <[email hidden]>

Quoted message said:

If I'm on my trainer, and I know what gear I'm in, and what my cadence
is, how would I calculate what speed I would be travelling on the road?

TIA,

-Bob

MPH = (Gear Inches * RPM) / 336.14 after dong the math.

Colin Campbell said:

Hell and High Water said:

If I'm on my trainer, and I know what gear I'm in, and what my cadence
is, how would I calculate what speed I would be travelling on the road?

TIA,

-Bob

One way would be to check speed while you are riding on the road at a
certain gear and cadence. For example, I have been forcing myself to
ride in smaller gears for the past ten days, and I know that if I'm in
my 53 x 19, going 28 kph, I'm pedaling just over 80 rpm. At 31 kph, I'm
right around 90 rpm. I admit I haven't tried really hard to get totally
accurate numbers.

So, on the trainer, you could take the cadence and gear combo, and
"solve" for speed, based on what you learned on the road.

You could also work it out with pencil and paper.
Get your wheel diameter (you usually set your bike computer to the
diameter in millimeters, something on the order of 2093 if you ride on
23 mm tires - check it for accuracy!),

get your gear ratio (39 x 19 is 2.05 revs of the wheel for every rev of
the pedals),

multiply these two numbers to get the distance traveled in one pedal
revolution at that gear ratio (2093 mm x 2.05 = 4290.65 mm),

multiply that by your rpm (4290.65 x 80 = 343252 mm / minute),

multiply that by 60 minutes (20595120 mm), and

divide by 1,000,000 to convert to kilometers / hour (20.6 kph, or about
13 mph).

You can make a spreadsheet that covers the ratios for all of your gear
combinations and several cadence values, and paste it on the wall next
to your trainer.

Or, you could move to California, where you don't need no stinkin' trainer!

Or forget about, it because the speed is 0 on a trainer and is in no way
comparable with your speed outside on the road.
People measuring speed and distance on a trainer don't get it IMO. Power
and/or time that's what counts.

Lou
--
Posted by news://news.nb.nu (http://www.nb.nu)

Hell and High Water said:

If I'm on my trainer, and I know what gear I'm in, and what my cadence
is, how would I calculate what speed I would be travelling on the road?

Try:

Speed (mph) = 0.0027 * Cadence * gear

But "riding" 20 mph on the trainer may be a lot easier (or harder)
than on the road.

Art Harris

In article <[email hidden]>, [email hidden] says...

Quoted message said:

Or forget about, it because the speed is 0 on a trainer and is in no way
comparable with your speed outside on the road.
People measuring speed and distance on a trainer don't get it IMO. Power
and/or time that's what counts.

No, but if I'm inside, spinning at 100 RPM, I'd like to know what speed
I'd be going when I'm outside.

Power has nothing to do with that mathematical calculation.

-Bob

Hell and High Water said:

In article <[email hidden]>, [email hidden] says...

Quoted message said:

Or forget about, it because the speed is 0 on a trainer and is in no way
comparable with your speed outside on the road.
People measuring speed and distance on a trainer don't get it IMO. Power
and/or time that's what counts.

No, but if I'm inside, spinning at 100 RPM, I'd like to know what speed
I'd be going when I'm outside.

May I asked why?

Quoted message said:

Power has nothing to do with that mathematical calculation.

True and it is not that difficult.

Lou
--
Posted by news://news.nb.nu (http://www.nb.nu)

Hell and High Water said:

In article <[email hidden]>, [email hidden] says...

Quoted message said:

Or forget about, it because the speed is 0 on a trainer and is in no
way comparable with your speed outside on the road. People measuring
speed and distance on a trainer don't get it IMO. Power and/or time
that's what counts.

No, but if I'm inside, spinning at 100 RPM, I'd like to know what speed
I'd be going when I'm outside.

If you were outside, would you be spinning at 100 RPM? And in the same
gear? The circumstances would be so much different.

Quoted message said:

Power has nothing to do with that mathematical calculation.

But what you propose is an incomplete mathemetical calculation.

In article <[email hidden]>, [email hidden] says...

Quoted message said:

Hell and High Water said:

In article <[email hidden]>, [email hidden] says...

Quoted message said:

Or forget about, it because the speed is 0 on a trainer and is in no way
comparable with your speed outside on the road.
People measuring speed and distance on a trainer don't get it IMO. Power
and/or time that's what counts.

No, but if I'm inside, spinning at 100 RPM, I'd like to know what speed
I'd be going when I'm outside.

May I asked why?

I'm messing around with cadence lately, trying to keep my cadence around
100.

So as I change gears while spinning, it's interesting to me to think
about riding out on the road, and the corresponding speed I would be
travelling...

That's not hurting anyone, is it?

;-)

-Bob

In article <[email hidden]>, [email hidden]
says...

Quoted message said:

Hell and High Water said:

In article <[email hidden]>, [email hidden] says...

Quoted message said:

Or forget about, it because the speed is 0 on a trainer and is in no
way comparable with your speed outside on the road. People measuring
speed and distance on a trainer don't get it IMO. Power and/or time
that's what counts.

No, but if I'm inside, spinning at 100 RPM, I'd like to know what speed
I'd be going when I'm outside.

If you were outside, would you be spinning at 100 RPM?

Quite possibly. I'm trying to keep my cadence around 100 lately.

Quoted message said:

And in the same
gear?

I've only got seven. The odds are pretty good I'll hit a few of the
same ones, be it inside or outside...

Quoted message said:

The circumstances would be so much different.

No kidding.

Quoted message said:

Quoted message said:

Power has nothing to do with that mathematical calculation.

But what you propose is an incomplete mathemetical calculation.

Nope.

Check out:

http://www.sheldonbrown.com/gears/

It's as simple as wheelsize/chainring/cog/rpm

Power is not an element.

-Bob

Hell and High Water said:

If I'm on my trainer, and I know what gear I'm in, and what my cadence
is, how would I calculate what speed I would be travelling on the road?

TIA,

-Bob

Dear Bob,

You can set up a spreadsheet and plug in the data, using rpm, front to
rear gear ratio, and tire circumference, print a card for quick
reference, and tape it to your handlebar.

100 revs / minute
x
53 / 12 rear tire spins / revolution
x
2120 mm / tire-spin
----
936,333 mm / minute (speed!)
x
60 minutes / hour
x
1/1,609,344 miles / mm ( 1 / (25.4 x 12 x 5280)
----
34.9 miles / hour (useful speed!)

Or you can buy a $10 Schwinn cyclocomputer at WalMart, rig a set of
quick-release mounts for the rear tire and top tube, put the magnet on
the rear spoke, and obtain the real-time accuracy that's crucial to
really enjoying going nowhere.

The cyclocomputer would also let you know how far you'd spun the rear
tire, how long, the average speed, and the maximum speed--you know,
all the digital details that separate us from the beasts that perish.

Cheers,

Carl Fogel

In article <[email hidden]>,
[email hidden] says...

Quoted message said:

Hell and High Water said:

If I'm on my trainer, and I know what gear I'm in, and what my cadence
is, how would I calculate what speed I would be travelling on the road?

TIA,

-Bob

Dear Bob,

You can set up a spreadsheet and plug in the data, using rpm, front to
rear gear ratio, and tire circumference, print a card for quick
reference, and tape it to your handlebar.

100 revs / minute
x
53 / 12 rear tire spins / revolution
x
2120 mm / tire-spin
----
936,333 mm / minute (speed!)
x
60 minutes / hour
x
1/1,609,344 miles / mm ( 1 / (25.4 x 12 x 5280)
----
34.9 miles / hour (useful speed!)

Or you can buy a $10 Schwinn cyclocomputer at WalMart, rig a set of
quick-release mounts for the rear tire and top tube, put the magnet on
the rear spoke, and obtain the real-time accuracy that's crucial to
really enjoying going nowhere.

The cyclocomputer would also let you know how far you'd spun the rear
tire, how long, the average speed, and the maximum speed--you know,
all the digital details that separate us from the beasts that perish.

Cheers,

Carl Fogel

Thanks so much Carl!

I'm also thinking about going to a roller. That would allow me to use
the cyclocomputer I've already GOT, right???

Any suggestions? (Other than to videotape it for YouTube!)

-Bob

Quoted message said:

Hell and High Water said:

Lou Holtman says...

Quoted message said:

Or forget about, it because the speed is 0 on a trainer and is in no way
comparable with your speed outside on the road.
People measuring speed and distance on a trainer don't get it IMO. Power
and/or time that's what counts.

No, but if I'm inside, spinning at 100 RPM, I'd like to know what speed
I'd be going when I'm outside.

Power has nothing to do with that mathematical calculation.

But power has everything to do with how fast you go on the road. If
you set up a roller and have tall enough gears on your bike, you can
get surface speeds on the rollers that are impossible when moving over
the ground. By decoupling the wheel's speed from ground speed and
airspeed, the wheel speed becomes irrelevant to how fast you'd
actually travel.

It's power to the wheel that decides your speed in the real world,
always. So use a power measuring device if you really have to know
that.

Chalo

Hell and High Water said:

In article <[email hidden]>,
[email hidden] says...

Quoted message said:

Hell and High Water said:

If I'm on my trainer, and I know what gear I'm in, and what my cadence
is, how would I calculate what speed I would be travelling on the road?

TIA,

-Bob

Dear Bob,

You can set up a spreadsheet and plug in the data, using rpm, front to
rear gear ratio, and tire circumference, print a card for quick
reference, and tape it to your handlebar.

100 revs / minute
x
53 / 12 rear tire spins / revolution
x
2120 mm / tire-spin
----
936,333 mm / minute (speed!)
x
60 minutes / hour
x
1/1,609,344 miles / mm ( 1 / (25.4 x 12 x 5280)
----
34.9 miles / hour (useful speed!)

Or you can buy a $10 Schwinn cyclocomputer at WalMart, rig a set of
quick-release mounts for the rear tire and top tube, put the magnet on
the rear spoke, and obtain the real-time accuracy that's crucial to
really enjoying going nowhere.

The cyclocomputer would also let you know how far you'd spun the rear
tire, how long, the average speed, and the maximum speed--you know,
all the digital details that separate us from the beasts that perish.

Cheers,

Carl Fogel

Thanks so much Carl!

I'm also thinking about going to a roller. That would allow me to use
the cyclocomputer I've already GOT, right???

Any suggestions? (Other than to videotape it for YouTube!)

-Bob

Dear Bob,

A roller spins the front tire at close enough to the same rate to the
rear that it would work.

But if you _really_ care about measuring your roller performance, you
won't settle for anything less than the models shown here:

http://www.bikecult.com/works/rollers.html

Shipping charges for this model may be a tad high:

http://www.bikecult.com/works/rollers/1900rollers.jpg

Cheers,

Carl Fogel

Quoted message said:

Hell and High Water said:

I'm also thinking about going to a roller. That would allow me to use
the cyclocomputer I've already GOT, right???

Any suggestions? (Other than to videotape it for YouTube!)

A roller spins the front tire at close enough to the same rate to the
rear that it would work.

But if you _really_ care about measuring your roller performance, you
won't settle for anything less than the models shown here:

The only roller which makes a serious attempt to synthesise road
riding (i.e. using both inertial and fluid dynamic brakes, in
dynamometer terminology) is the TruTrainer
http://www.trutrainer.com/products_rollers.shtml

After you've lashed out the best part of $1000 on rollers, getting a
PowerTap or SRM to really tell you what you're doing won't seem so
expensive :-)

By the way, for quick and dirty calculations you can do in your head
remember that 100rpm on 100" gear is within 1% of 30mph

Kinky Cowboy*

*Batteries not included
May contain traces of nuts
Your milage may vary

Hell and High Water said:

In article <[email hidden]>, [email hidden]
says...

Quoted message said:

Hell and High Water wrote:

[..]

Quoted message said:

Quoted message said:

Quoted message said:

Power has nothing to do with that mathematical calculation.

But what you propose is an incomplete mathemetical calculation.

Nope.

Check out:

http://www.sheldonbrown.com/gears/

It's as simple as wheelsize/chainring/cog/rpm

Power is not an element.

But it is when you factor in real world variables like rolling
resistance, aerodynamics, gravity (when going uphill), etc.

On Oct 10, 3:03 pm, [email hidden] wrote:
(snip) you know,

Quoted message said:

all the digital details that separate us from the beasts that perish.

Are you saying you don't believe in Dog Heaven, Carl?

IMS, I think you saw a hopeful snake once.

Too bad we don't get the answers to these questions here first
(assuming, of course).

--D-y

email hidden said:

On Oct 10, 3:03 pm, [email hidden] wrote:
(snip) you know,

Quoted message said:

all the digital details that separate us from the beasts that perish.

Are you saying you don't believe in Dog Heaven, Carl?

IMS, I think you saw a hopeful snake once.

Too bad we don't get the answers to these questions here first
(assuming, of course).

--D-y

Dear D,

Of course there's a Dog Heaven--it's for dogs, who will be allowed to
visit.

Cats are another matter. Let us simply say that they prefer a warmer
climate and leave it at that.

For those whose scriptural knowledge is deficient:

http://www.google.com/search?as_q=%22beasts+that+perish%22+wodehouse&hl=en&num=10&btnG=Google+Search&as_epq=&as_oq=&as_eq=&lr=&as_ft=i&as_filetype=&as_qdr=all&as_nlo=&as_nhi=&as_occt=any&as_dt=i&as_sitesearch=&as_rights=&safe=images

It appears in other books of the canon not yet available on the net.

Cheers,

Carl Fogel

nmp said:

Hell and High Water said:

In article <[email hidden]>, [email hidden] says...

Quoted message said:

Quoted message said:

Or forget about, it because the speed is 0 on a trainer and is in no
way comparable with your speed outside on the road. People measuring
speed and distance on a trainer don't get it IMO. Power and/or time
that's what counts.

Quoted message said:

No, but if I'm inside, spinning at 100 RPM, I'd like to know what speed
I'd be going when I'm outside.

If you were outside, would you be spinning at 100 RPM? And in the same
gear? The circumstances would be so much different.

Quoted message said:

Power has nothing to do with that mathematical calculation.

But what you propose is an incomplete mathemetical calculation.

gear inches x .2973 = mph @ 100 rpm (roughly)

I figured it out once when I wanted to be able to determine cadence
without a cadence-equipped cyclocomputer on my fixie. It's pretty
easy to remember the value for a given gear combo, then adjust for a
particular speed. For example, if I'm out tooling around in a 42x16
(or 70.8 GI) I know that at 21 mph I'm doing approx 100 rpm. Given
that, I know that 10 rpm = 2.1 mph. So, even in a fixie-induced haze
I can quickly tell that 18.9 mph = 90 rpm, 23.1 mph = 110 rpm, etc...
That way I don't need huge chart. I only need to know the mph @ 100
rpm speed for the given gear I'm using.