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Power, cadence and gear ratio calculator?

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Power, cadence and gear ratio calculator?

Old 11-12-19, 05:58 AM
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bartek. 
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Power, cadence and gear ratio calculator?

Hi,

It took me few hours with nothing however I am almost certain sure that someone shared the link on this forum. I'm looking for a calculator between power, cadence and gear ratio. Simply to set a specific gearing for required power and cadence.

Anyone know a place to find it or formula?

Cheers
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Old 11-12-19, 07:40 AM
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Originally Posted by bartek. View Post
Hi,

It took me few hours with nothing however I am almost certain sure that someone shared the link on this forum. I'm looking for a calculator between power, cadence and gear ratio. Simply to set a specific gearing for required power and cadence.

Anyone know a place to find it or formula?

Cheers
I don't think I've seen a calculator that includes power - that's because, in order to translate power to cadence through gear ratio (all of that is essentially speed), you have to chart a course through a bunch of other variables that few people know for themselves, and are pretty tricky to measure in the first place.
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Old 11-12-19, 07:48 AM
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Yeah, it's crucial for speed charts (wind, tyres, cda etc.) but I don't think it's that important if I'm not interested in speed numbers. Surely, by using training rollers where a total resistance is super low, for the same gear ratio and cadence, the power output will be much lower. However, as I would like to use it in controlled environment, such like velodrome, most of the resistance is quite/enough stable to get pretty accurate (or stable) results I believe.
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Old 11-12-19, 07:58 AM
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It's not possible.

You may be thinking of Kurt Kinetc where they provided some maps of "X speed = Y power" based on the resistance required to move their fluid trainer's drum a certain speed. But, that X = Y equation only works when using that particular trainer. The formula would be different for a different fluid trainer.
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Old 11-12-19, 08:29 AM
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Originally Posted by bartek. View Post
Hi,
Simply to set a specific gearing for required power and cadence.
Anyone know a place to find it or formula?
Cheers
Once given a known Power x Speed curve, its easy to build on a simple Excel table/curve.

I use it to choose gears when targeting a rpm-watt spot on roller intervals, but I have the Power x Speed curve for it, bike/wheels/tires/pressure being kept the same.

Its like.. I know I will need 400w when going at 45 kmh at the rollers, and I want to deliver it at 100rpm, which will be the best gears for it?.
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Old 11-14-19, 04:23 PM
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Originally Posted by Clythio View Post
Once given a known Power x Speed curve, its easy to build on a simple Excel table/curve.

I use it to choose gears when targeting a rpm-watt spot on roller intervals, but I have the Power x Speed curve for it, bike/wheels/tires/pressure being kept the same.

Its like.. I know I will need 400w when going at 45 kmh at the rollers, and I want to deliver it at 100rpm, which will be the best gears for it?.
Hmmm this is more or less what I'm looking for. As I'm understanding you just used your known data (power x speed) from previous workouts to make the curve?
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Old 11-14-19, 05:56 PM
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Originally Posted by bartek. View Post
Hmmm this is more or less what I'm looking for. As I'm understanding you just used your known data (power x speed) from previous workouts to make the curve?
Yes...or previous real world efforts.
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Old 11-15-19, 09:46 AM
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Originally Posted by bartek. View Post
Hmmm this is more or less what I'm looking for. As I'm understanding you just used your known data (power x speed) from previous workouts to make the curve?
Exactly. Powermeters all the time. My roller, same conditions, try to use same pressure etc.
But of course you can build a real world, outdoors, speed x power curve and work over it.
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Old 11-18-19, 03:38 PM
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To add a dose of reality...

If you are a sprinter, just about all of your training will be maximal. The variation will be in volume. The intensity will be maximum.

If you are an all-arounder or pursuiter, you'll have to train operating in "The Pain Cave", and that simply boils down to training against heart rate or RPE.

Having trained with power meters for years and logging so many workouts and races, power really just shows what the end result is of a lot of other upstream factors. For example, for pacing efforts, the heart controls how long power is applied, not the other way around. Watch the heart rate and you'll have a better idea as to how you are *currently* doing and whether you can turn it up a notch or turn it down. The Power being recorded is just the output of all of that, just like the speed or time of the effort.
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Old 11-18-19, 03:54 PM
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Originally Posted by carleton View Post
To add a dose of reality...

If you are a sprinter, just about all of your training will be maximal. The variation will be in volume. The intensity will be maximum.

If you are an all-arounder or pursuiter, you'll have to train operating in "The Pain Cave", and that simply boils down to training against heart rate or RPE.

Having trained with power meters for years and logging so many workouts and races, power really just shows what the end result is of a lot of other upstream factors. For example, for pacing efforts, the heart controls how long power is applied, not the other way around. Watch the heart rate and you'll have a better idea as to how you are *currently* doing and whether you can turn it up a notch or turn it down. The Power being recorded is just the output of all of that, just like the speed or time of the effort.
Outstanding, accurate, and relevant post!
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