Strava and Garmin.

[gavroche]

Every time I go for a ride, I always start both of them at the same time.
When I get back, both them show a different average kmh with Strava always 1 kmh lower than Garmin, so which one is the most accurate?

 

[Ming the Merciless]

Time for your stopwatch and a clicker odometer

 

[cyberknight]

assuming you are using the same data then garmin will be slightly more accurate as strava applies some math that smooths out gps tracks that can cut corners etc and afaik they handle the elevation date differently .
If your using different devices to record then the different sampling rates and accuracy of the devices can also affect the figures .

 

[nogoodnamesleft]

Any pauses. Even if both systems have auto pause enabled they will ise different paise criteria.

I have an "old school" wired cycle computer (wired wheel sensor) and Garmin running using an ANT wheel sensor, same wheel and manually set same calibration. Both give different average speeds on the same ride.

 

[YMFB]

I regularly ride with the same two people, all three of us have iphones, two of us have Garmin 1030 +. All three of us have varying elevations and distances. The variations are probably less than 1% so an acceptable degree of accuracy.

 

[figbat]

Out of curiosity, why are you running both in parallel? Why not record in one (say Garmin) and import the data to the other?

 

[N0bodyOfTheGoat]

By default, I believe Strava's average speed shows moving speed, rather than distance covered since starting and stopping the recording including you waiting at lights; junctions etc.

 

[PaulSB]

By default, I believe Strava's average speed shows moving speed, rather than distance covered since starting and stopping the recording including you waiting at lights; junctions etc.

Well, yes and no. Strava displays what the device has recorded and this will generally be:

Elapsed time - start to finish
Moving time - auto-pause is inactive
Paused time - auto-pause active
Average speed - distance and moving time

For me paused time is at lights, junctions, pee stops, cafes. The auto-pause speed activation can be set by the rider.

So it isn't a default applied by Strava but a result of how the devices are set up, used and record. I only have experience of Wahoo and Garmin units but I imagine others are very similar.

 

[Dogtrousers]

They are both just as accurate as each other as they each have their own definition of the concept of "moving average speed".

The Strava Moving Average Speed is the Strava Moving Average Speed. It is what it is. It's 100% accurate. Same goes for Garmin Moving Average Speed.

Moving Average Speed is a bit of a bullshit metric that is estimated from imperfect data.