# how accurate is strava?



## shekky (Oct 21, 2011)

in terms of the speeds it records on a ride?






here you will see that strava has recorded my top speed at 49.0 mph, which i think is closer to 44-45 mph. in addition, the performance graph only shows a maximum speed of 32 point something mph.

can anybody share informed insights as to how this all works?


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## Harold (Dec 23, 2003)

What was your recording interval and why do you think you went the speed you think you went?


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## shekky (Oct 21, 2011)

i just don't think i was going almost fifty. i braked to soon past my normal braking spot where i attain my daily high speed. recording interval? what's that?

yesterday the speed/power/elevation graph wasn't completely correct because it might have taken strava a bit to process and fine tune the data. 

you're a good man, nate...you always chime in on these...


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## Silverwulf (Feb 24, 2012)

I did the EXACT same ride 2 weekends in a row and my distance was different by
.4mi???


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## shekky (Oct 21, 2011)

Silverwulf said:


> I did the EXACT same ride 2 weekends in a row and my distance was different by
> .4mi???


yeah, but our side jaunts which might not reflect on the map my be the difference there...


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## twobournes (Sep 10, 2008)

I use strave myself. I believe in terms of top speed there are certainly some times that it over estimates. I believe this to be instances in which the gps signal goes funky. I've recorded top speeds of mid 50's before on rides that I barely got over 40 (if that). I've done over 50mph before, and its a pretty unforgettable feeling. Anyway, in other terms I think it is as accurate as any gps based unit on the market. I show distance variances on the same route as well, but again - sometimes the gps signal gets screwy and other times it stays steady (based on the mapping of the ride). My regular computer is slightly more accurate regarding the mileage, speed, etc... but Strava is usually pretty close.


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## KrisRayner (Apr 3, 2007)

I don't think it's Strava that's the problem, but more likely the device that's doing the GPS calculations. I've uploaded past rides from a Garmin GPS I had and compared them to my most recent rides using an iPhone. Same trail, and the Garmin was way more consistent where as my iPhone would vary by .2 of mile on the same 3 mile stretch.


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## Silverwulf (Feb 24, 2012)

Yeah.....I'm using an iphone4. I plan on getting a garmin edge 500 in the next few weeks. Maybe that will help with consistency. I was on my roadbike and hit 80kph. And I was riding the brakes. I'm pretty sure that was accurate though. As one poster said, it's an unforgettable feeling!


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## Camel Toad (Nov 23, 2011)

Here's some data that I have from a ride that I tracked with iPhone 4S Strava app & Garmin Forerunner 410. You can see some slight differences.

*Device	Garmin Forerunner 410*
Time	01:16:11
Distance 21.0mi
Elapsed Time	01:16:11
Max Speed	24.4mph
Avg Speed	16.6mph
Cadence	N/A
Bike Redline D440

*Device	Strava iPhone App*
Time	01:17:22
Distance 21.2mi
Elapsed Time	01:48:49 (i forgot to stop the app after the ride for a bit)
Max Speed	26.5mph
Avg Speed	16.4mph
Cadence	N/A
Bike Redline D440


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## KrisRayner (Apr 3, 2007)

We're you recording the same ride simultaneously?


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## Harold (Dec 23, 2003)

Since you're using a phone app it's important to know how they work. Phone gps hardware is not as good as dedicated hardware. To lessen the gap, good apps (like strava) "massage" the data and do heavy processing to close the gap...but there is still a gap which will vary from phone ro phone. Unfortunately phone mfrs do not say any more about which gps hardware they use so it's very hard to compare head-to-head.

That will result in the occasional inaccuracy and variability in measurements.

Recording interval is the frequency a position is recorded. All dedicated receivers and some apps let you specify this. If your recording interval is too long and your apeed changes during that interval then you have inaccuracies. Also a simgle errant point can result in an outlier speed. All sorts of thing can be the problem


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