Strava

How is watts calculated on Strava?

Strava Glossary

Badly.

Exactly what I was going to say.

The Strava calculated power is taken in preference to power meter measured power, for example 5 and 10 minute power figures, which is a bit odd.

Badly.

( it's covered up-thread )

It's really not that bad (as covered earlier in the thread). People just shouldn't expect anything even remotely accurate if they're using damn iphone/strava apps where the plotted course of a ride is wildly flying all over the place all the time.

If you're travelling at a fairly constant speed and you have your weight and your bikes weight put in correctly, AND use a decent GPS device you should be able to be fairly confident of a reliable estimate

Strava Calculated Power vs. Power Meter
We have seen that in most cases our watts number are very close to the numbers provided by a Powertap or SRM. Note that Strava calculated watts are not the watts produced at the crank but the watts produced by the rider-bike system, this will create a slight difference between the powermeter data and the Strava watts. Lack of good chain lubrication and low tire pressure can rob you of the watts you see on your Powertap or SRM. Other reasons watts can be inconsistent include strong winds and bad elevation data reported by the Garmin.

Our calculations are most accurate when climbing given accurate rider and bike weight.

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The Strava calculated power is taken in preference to power meter measured power, for example 5 and 10 minute power figures, which is a bit odd.

I imagine it justs grabs whichever ride data presents a larger figure. If that comes from a non-SRMed Stravawatt calculation then you'll just have to pedal harder to get it to switch over.

The Strava calculated power is taken in preference to power meter measured power, for example 5 and 10 minute power figures,

... if you're not signed up to premium membership.

If you're travelling at a fairly constant speed and you have your weight and your bikes weight put in correctly, AND use a decent GPS device you should be able to be fairly confident of a reliable estimate
It is pretty accurate for climbs (weight of rider and bike is by far the most influencial variable here). But for going fast on the flat it is usesless as it has no information about drag and doesn't take into account wind or drafting.

^ This.

If you ride with a group (of not nodders) then this matters.

... if you're not signed up to premium membership.

Eh? I am a premium member, Strava takes it's own calculated power in preference to that of my power meter.

Even, I am led to believe, when the power meter figure is higher (I've not checked that, info from the Wattage forum).

Oh.. I've got the power reading and heart-rate / ride intensity thing mixed up (and didn't realise you had premium).

That is bizarre then - very strange that they'd set it up choose their 'ok' power calculator over a device that can read it so much more accurately

Thanks for pointing out is was in the glossary/explaining!

This looks fun.
http://app.strava.com/segments/823503

strava'd my commute...

yeah!

http://app.strava.com/rides/19121856

^Careful, with that sort of mileage on your commute I can only hope you have a rest/refuel stop planned halfway ;-)

two bananas in the jersey, gel under the shorts, and double bottles OBZLY

real question is, do I invest in some clip-on extensions for that one segment?

Yeah that segment looks pretty serious. Don't forget your EPO - I won't tell if you won't

"Don't Race me again"? I'd love to know who set that up...

whoever it is, he definitely went there at 4am and RLJ'd. there's a crossing that always catches you out

Just got notified that some total loon just toppled me after having this one for nearly 4 months.

Did it some time this morning too..... jumping reds during post rush hour traffic must have been interesting

http://app.strava.com/segments/995917

http://app.strava.com/segments/940877

I lost upper street to someone like that. only managed that as I was hyped after the marathon ride and the roads were empty.

Love the BS elevation profile for that. It shows up as -3% -4% +3.5% etc all over the place.

Is it a bmx tarck?

Not me http://app.strava.com/runs/18625394

Someone just took my KOM with a power reading of 739W. Is he doping?

Maybe he's just a fatty with a tailwind.

Someone just took my KOM with a power reading of 739W. Is he doping?

I've had this happen twice. A whole bunch of us with similar times, can't remember thr specifcs but for example around 3:45 then someone comes along and does a 2:05 at 850w. A quick delve into their profile reveals they normally ride at closer to 120w and their 10 min power record is 200w. So how are they suddenly able to go on an isolated ride typically halving every KOM time as they pass through each segment ar 400w for 2 hours. Clearly corrupt data.

If they don't realise and do the right thing (delete the ride) then you can "flag" their ride. Strava then look at it and either decide it's not legit and remove it or decide its genuine, reinstate the ride and drop Sky a note that there's a new world champion cruising round Britain demolishing KOMs for breakfast. At least I think that's how it works.

Yeah- I reckon I should flag this McEvoy character- he pulled ~750 watts up the hill I live on