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.

 

[Sea of vapours]

Well, yes and no. Strava displays what the device has recorded

Have you compared your average speed, for a single ride, on both your Wahoo and on Strava (assuming here that the data in Strava came from the Wahoo, not from Strava running on a phone)? Unless you've not stopped at all, they won't necessarily be the same. It depends on what autopause settings you have on the Wahoo, since that will affect the recorded data. In the case where the Wahoo is not autopausing at all, Strava still applies its own algorithm to determine moving and stopped time and the average speed it displays is based on moving time (it also shows elapsed time, but that is not what average speed is based on). The two figures may be quite similar if the Wahoo is autopausing, but they're unlikely to be the same. (I presume this is also true when using a Garmin, or whatever, device for the input data to Strava.)

 

[Ming the Merciless]

I presume this is also true when using a Garmin

It is, Strava comes up with its own moving and stopped, even when the source is Garmin. For me the Strava one is often 0.1 to 0.4 km/h lower moving than what Garmin Connect says. I have auto pause turned off, as that can inflate your moving speed.

 

[gavroche]

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

I do it in case one fails.

 

[PaulSB]

Have you compared your average speed, for a single ride, on both your Wahoo and on Strava (assuming here that the data in Strava came from the Wahoo, not from Strava running on a phone)? Unless you've not stopped at all, they won't necessarily be the same. It depends on what autopause settings you have on the Wahoo, since that will affect the recorded data. In the case where the Wahoo is not autopausing at all, Strava still applies its own algorithm to determine moving and stopped time and the average speed it displays is based on moving time (it also shows elapsed time, but that is not what average speed is based on). The two figures may be quite similar if the Wahoo is autopausing, but they're unlikely to be the same. (I presume this is also true when using a Garmin, or whatever, device for the input data to Strava.)

No, I hadn't until five minutes ago! 🤣 My Wahoo is set to auto-pause and does so when I stop and restarts as soon as I begin to move.

My last ride is shown below:

Wahoo

Strava

 

[steverob]

I sometimes find a 0.1 difference in speeds between Garmin and Strava and for me at least, it seems that Garmin will round up to 14.2 when it is 14.16, but Strava only ever rounds down.