How accurate is Strava calculated power

littledove44

According to their website the Strava calculations are quite similar to readings from power meters. It would be easy to say "of course they would say that" but I was wondering if anyone had actually made the comparison themselves.

The reason I ask is that I recently did a ride and had some, for me at least, awesome power readings. It would be nice to know if I can feel good about this or not.

JackPozzi

Not looked into in depth, but would suspect it might be able to have a reasonable guess on very steep climbs assuming you've entered correct weights for bike and yourself. For most sections though it'll be slightly more accurate than a random number generator. Most of the time.

chris_bass

I dont it will be about as accurate as the calorie count, in that it is very inaccurate.

it has no way of knowing if you are cycling into a 40mph headwind or with a tailwind, you could be on incredibly rough road surfaces or the smoothest tarmac know to man.

Grill

It's not even close. Having done many segments with my PM I can say this with absolute certainty. It wouldn't be a big deal if there were consistency in the numbers, but as Chris pointed out the lack of environmental data 86's that.

DHA987S

For comparison on a short (0.2 mile) uphill sprint segment near me.

Strava estimated my average power to be 503W, riding the same segment with a power meter average power was 400W and max was 579W. The ride with the power meter was 3 seconds slower than the ride without. It's "similar" but not accurate.

A longer climb (1.3 miles)

Strava estimate average power 145W, actual power average 203W max power 337W.

Grill

Downhill is hilarious with Strava. Amazing how I managed to KOM with over 200 watts less than the runner up!
http://www.strava.com/segments/4420588

imposter2.0

littledove44 wrote:

The reason I ask is that I recently did a ride and had some, for me at least, awesome power readings. It would be nice to know if I can feel good about this or not.

If you want to feel good about something, then feel good about the times, not the power readings.

charlie_potatoes

I did last year's Ride London at above my (then) FTP according to Strava

FatTed

On steep climbs cycling alone when the wind and drafting are not a factor, and provided you have put the correct weight for you and the bike and water bottles it seems reasonably accurate to me.

littledove44

Charlie Potatoes wrote:

I did last year's Ride London at above my (then) FTP according to Strava

My recent Cape Argus was similar. 30% above my ftp for four hours.

Grill

FatTed wrote:

On steep climbs cycling alone when the wind and drafting are not a factor, and provided you have put the correct weight for you and the bike and water bottles it seems reasonably accurate to me.

So you're going to adjust bike weight based upon how much water you're carrying at any given time? Sounds like a fun way to spend an evening.

secretsqizz

For someone who appears to have enough disposable income.. get yourself a powertap for jimmies sake and have done with it... come back and give us awsome but true stats of a 148 watt ride for 5 hours......in fairness not too shabby for a hobby cyclist.

al_kidder

Grill wrote:

FatTed wrote:

On steep climbs cycling alone when the wind and drafting are not a factor, and provided you have put the correct weight for you and the bike and water bottles it seems reasonably accurate to me.

So you're going to adjust bike weight based upon how much water you're carrying at any given time? Sounds like a fun way to spend an evening.

Yes. It's easy enough. The real variable is how much sweat you have lost on the route to the bottom of the hill. Going up steep hills means slow riding, so almost all of your effort is going into lifting yourself up the hill, not overcoming wind and friction. That's an easy calculation to get average power for even the thickest of high school physics students

Grill

Al Kidder wrote:

Grill wrote:

FatTed wrote:

On steep climbs cycling alone when the wind and drafting are not a factor, and provided you have put the correct weight for you and the bike and water bottles it seems reasonably accurate to me.

So you're going to adjust bike weight based upon how much water you're carrying at any given time? Sounds like a fun way to spend an evening.

Yes. It's easy enough. The real variable is how much sweat you have lost on the route to the bottom of the hill. Going up steep hills means slow riding, so almost all of your effort is going into lifting yourself up the hill, not overcoming wind and friction. That's an easy calculation to get average power for even the thickest of high school physics students

Funny how Strava still manages to screw it up...

slowbike

depends what you take the accuracy level to be ... to the nearest 100w it's probably not that far out ...

sloppyschleckonds

Grill wrote:

Downhill is hilarious with Strava. Amazing how I managed to KOM with over 200 watts less than the runner up!
http://www.strava.com/segments/4420588

Drafting

Grill

SloppySchleckonds wrote:

Grill wrote:

Downhill is hilarious with Strava. Amazing how I managed to KOM with over 200 watts less than the runner up!
http://www.strava.com/segments/4420588

Drafting

How does one draft solo with no cars on the road?