Strava

Strava tends to be pretty weak when it comes to power estimation on anything except climbs. There's no way to know how close or far off your particular estimate is, but in general for variable terrain riding Strava power estimates tend to be quite high.

Thats what I thought. I guessed that 220 w during almost 3 hours and feeling comfortable is to good to be true... Thanks for your reply!

Well I see that Strava is way off ....

In my experience, it's frequently all over the place. Sometimes it's absurdly high, whereas on occasion it'll be 10% lower that what my meter reads (maybe my meter sucks, or needs calibration).

They made a good effort to measure power but it's not there yet.

Quoted post said:

Originally Posted by bradg [IMG]/img/forum/go_quote.gif[/IMG]...They made a good effort to measure power but it's not there yet.

It's just a really challenging problem that is tough if not impossible to solve accurately. They can know speed and elevation gain but have to guess on road surfaces, wind speed and direction, drafting or not, position on bike, air density, even tires and tubes and pressures you're running not to mention whether you braked a lot. Pretty hard to guess all that based on speed and elevation alone.

-Dave

Even with a power meter I find differences where WKO+ and Garmin Connect are almost always identical with TSS, IF and AP and Strava has different values.

Quoted post said:

Originally Posted by bradg [IMG]/img/forum/go_quote.gif[/IMG]

In my experience, it's frequently all over the place. Sometimes it's absurdly high, whereas on occasion it'll be 10% lower that what my meter reads (maybe my meter sucks, or needs calibration).

They made a good effort to measure power but it's not there yet.

Just for [censored] and giggles I went to Strava to see times for the Bear Mountain hill climb (In New York):
app.strava.com739813Open ↗

The power outputs seem to be all over the board, from highs around 400, to a number in the 200's and then some lower anomolies. It seems that some of the outputs corresponding to times within a few seconds vary by as much as 100+ watts. But going back to what Dave mentioned about closer consistency of power on climbs, even with the wide variance there does seem to be some correlation on many of the times, but indeed it's not there just yet.

This particular hill climb course was my first competitive cycling event back in 1982 and my 15:15 was good for 2nd place. The exciting thing is now as a Garmin owner and new Strava member I am going to see how close we can get to that old time. The less than exciting reality is that I will probably not be able to get close to that 15 year old animal I used to be. [IMG]/img/vbsmilies/smilies/hissyfit.gif[/IMG]

Quoted post said:

Originally Posted by danfoz [IMG]/img/forum/go_quote.gif[/IMG] The power outputs seem to be all over the board, from highs around 400, to a number in the 200's and then some lower anomolies. It seems that some of the outputs corresponding to times within a few seconds vary by as much as 100+ watts.

Well that's to be expected, as people weigh different amounts, and draft different amounts and all sorts?

The KOM and QOM here 8 seconds apart and 80 watts apart
app.strava.com629674Open ↗
We rode up together with real power meters.

Quoted post said:

Originally Posted by JibberJim [IMG]/img/forum/go_quote.gif[/IMG]

Well that's to be expected, as people weigh different amounts, and draft different amounts and all sorts?

The KOM and QOM here 8 seconds apart and 80 watts apart
app.strava.com629674Open ↗
We rode up together with real power meters.

What do the little lightning bolts mean - are those actual PM readings as opposed to extrapolated values?

Yes those are "actual" power numbers. Actual, meaning the XML file uploaded contains power data. My Powercal data shows up with a lightning bolt.

BTW - you can fake the XML data to your heart's desire. The data in Strava is more or less on the honor system - still fun to use though.

Quoted post said:

Originally Posted by Felt_Rider [IMG]/img/forum/go_quote.gif[/IMG]

Even with a power meter I find differences where WKO+ and Garmin Connect are almost always identical with TSS, IF and AP and Strava has different values.

That's because Strava uses the same system as Golden Cheetah with real power for calculating intensity and stress, whereas WKO+ is slightly different. If you use Golden Cheetah you'll see that Strava's weighted average power is the same as Xpower.

Thanks smaryka
That is good info rather than me thinking it was it is miscalculated.

Quoted post said:

Originally Posted by maydog [IMG]/img/forum/go_quote.gif[/IMG]

BTW - you can fake the XML data to your heart's desire. The data in Strava is more or less on the honor system - still fun to use though.

Healthy doping [IMG]/img/vbsmilies/smilies/smile.gif[/IMG]