B1KE

I use my smartphone to app to log times on Strava but once I upload to strava the states are different than from my phone gps. For example my last rime was

1 hour 3 minutes on my phone app
1 hhour 8 minutes on strava

My max speed on my phone app was 52km
My max speed on strava was 56km

My average speed was 26.6km on my phone
My average speed on Strava was 24.3

Does anyone else experience such differences between their native gps phone app and Strava?

TrojanHorse

It probably just has to do with how your phone and Strava interpret "breaks" differently. I wouldn't worry about it at all. Same data, just parsed differently.

rm -rf

All gps software uses smoothing. My Garmin 705 records once a second, and is accurate enough to show which side of the road I was on. But even so, there's "jitter" in recordings, and the different sites have their own way of fixing the raw data.

I have a wheel sensor feeding the Garmin, so it knows when I'm stopped. A phone GPS needs to guess, since even when stopped, the current location drifts, and it looks like you are moving at random.

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I often get three different average speeds on ridewithgps.com, strava.com and My Tourbook running on my PC.

For instance, here's 4 minutes of My Tourbook with smoothing turned off. Notice the huge Feet per Hour in yellow. In real life, I can sustain about 2000 feet per hour, and maybe 3000 for a very short hill.



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And the same thing with the smoothing settings I use. The max speed is lower. The rest of the chart looks more reasonable. And even here, the yellow feet per hour is still not right. But if I increase the smoothing even more, it just rounds off all the highs and lows too much.



My Tourbook is free software that runs on your own computer. It has tons of features for tracking rides and viewing them on maps.

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Here's a zoomed in My Tourbook map showing each one-per-second data point, color coded by speed. First, heading uphill to the top of the map, then returning downhill and turning left.

You'd think that something this accurate wouldn't need any smoothing.

B1KE

Thanks for the help. In this situation its it my GPS device that shows the more accurate speed or Stavas interpretation?

K.Katso

If you're concerned about accuracy of the GPS data, then get a computer with a GPS, like a Garmin. Every time I see some bizarre segment time on Strava, like someone doing 248km/h on a segment (no kidding), the device is always listed as "Strava iPhone App" or "Strava Android App." You almost never see things like that with a Garmin. Of course there is still going to be a little bit of sampling error but I've found that the real computers have much more accurate data than smartphones. Plus you can get power and heart rate data too.