Originally Posted by
Tourist in MSN
It has been a few years since I did those calcs. Basically I did a horsepower calculation first then, converted to watts.
I just did a google search, found this (pasted):
Explanation: The term "horsepower" was coined by James Watt to describe the power needed to lift 550 pounds one foot in one second, essentially comparing the power of a steam engine to that of a horse
So, it was pretty easy using that to calculate from my weight with bike, the hill height was 95 feet based on several readings from my GPS, and how long it took me to pedal up it. That gave me my horsepower (or fraction of it), then converted that to watts.
That hill is near my home, if I want to do hill training, I do a loop that includes that hill. Thus, from elevation profiles I have dozens of measurements for height of hill from my GPS.
I'd always assumed that Strava's power estimates were based on those simple calculations, and that their estimates on average power on a climb* aren't as bad as some think. You can even enter your weight and the weight of your bike.
* the longer/higher the climb, the better. And the fewer environmental factors (i.e.., wind, road surface, etc...) the better.