Polar to add MANUAL STRYD Calibration

9 May 2019

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Yay !

Lots of people are going to be happy that Polar will be including manual footpod calibration in the V4 release for October 2019.

It’s taken a while, with pressure and polite requests from many sources. October is still a little bit too far away for my liking as I had hoped to use STRYD+Vantage M for my races this year…oh well. Next year.

I’m still not entirely why *I* need to use manual calibration but, for me, the results of the auto calibration do not feel right on the Vantage.

Here is my+STRYD’s understanding of Vantage’s capability to get pace and distance AUTOMATICALLY from a foot pod ie how it seems to work now

Vantage will get pace and distance from foot pods
Vantage will adjust the calibration factor over time so the pace and distance from the foot pod matches GPS in terms of absolute values
Vantage will not reveal the calibration factor or allow the users to change the calibration factor

So, it seems to ME, that the reason why STRYD+Vantage appears inaccurate is either the incorrect adjustment over time by the Vantage OR the runner not allowing the algorithm sufficient time to bed in. And, sorry, I don’t know what ‘sufficient’ time is.

Auto calibration seems to work OK for me on the 935

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21 Comments

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Mikl

1 year ago

doublon

Mikl

1 year ago

Be careful don’t be confused Stryd and Stride

https://www.polar.com/fr/produits/accessoires/Capteur_de_foulee_Bluetooth_Smart

Stu

1 year ago

It doesn’t help that Polar doesn’t describe clearly how auto-calibration works or at least give a feature where you can see what the autocalibration value arrived at is and lock it in if you’re generally happy with it. I have a feeling that it may be calibrating near the start of each run which can work ok but can also work really really badly. If you run just based on GPS then you might expect some parts to overegg distance and some parts to underreport – on average things have a tendency to shake out ok. But the instant pace can be less than desirable. Normally my distances with Vantage V and Stryd are ok for distance but normally I’m running in the country. Today started in the city surrounded by tall buildings; end distance according to (autocalibrated) stryd was 8.8km; according to the exported GPS TCX more like 7.6km. I accept I need to redraw the route on MapMyRun to get a judgment but I believe the average pace implied by the shorter distance. What I think may have happened is the calibration factor got locked in at the beginning, surrounded by tall buildings and poor gps quality. The… Read more »

tfk, the5krunner

Author

Reply to Stu

1 year ago

yes i think something broadly along those lines might be happening. though i suspect claibration would be continuous in some way.
to test: go for a nice open 3k run and then finish through the tall buildings.

Jormaperti

Reply to Stu

1 year ago

Hi,

As a workaround, you can manually calibrate your Vantage+Stryd combo if you have access to an older Polar device which supports manual calibration of a foot pod (like V800).

If it isn’t your V800, you may want to factory reset it before beginning. Connect it to your Flow account. Pair your Stryd with V800. Enter the correct calibration factor in the V800 settings and then sync V800 to your Flow account. Then sync to Flow again, but this time do it with your Vantage, and you will have your new calibration factor in it (no way to check it in settings or anywhere, though). And of course, before returning your friend’s V800, you may want to factory reset it again 🙂

Happy training!

tfk, the5krunner

Author

Reply to Jormaperti

1 year ago

10/10 if it works. Seriously impressed with that !!

TimFr

Reply to Jormaperti

1 year ago

Can any one confirm that this actually works? I’ve been thinking of buying the Vantage M, but the lack of manual calibration is turning me off because my Stryd is so inaccurate. Would this procedure work with the Vantage M and the M400? Also does anyone know if the Vantage M allows you to get speed from footpod with GPS on?

Beroman

Reply to Jormaperti

1 year ago

Have you validated this? I tried this but there is a difference between running with V800+Stryd and VantageV+Stryd. To my knowledge Vantage with GPS on will always use auto-calibration and with GPS off it will use factor 1.000 and not my manual setting of 0.951. https://support.stryd.com/hc/en-us/articles/360019450474-Can-the-Polar-Vantage-M-and-V-use-Stryd-for-pace-and-distance-/?utm_source=tfk&utm_medium=b&utm_campaign=r

Cristian

Reply to Jormaperti

1 year ago

It does not work. Simply put, the calibration factor is on the receiver, not on the pod. And yes, I tried this with both a V800 and the Polar Beat app.

The only way to go on the default 1.00 calibration factor of a pod (any pod) and avoid auto-calibration on the Vantage is to (in order):
1. Factory reset your Vantage
2. Disable GPS on the profile you use
3. Exercise

Polar on the S1 footpod: https://support.polar.com/za/support/FAQs_S1

tfk, the5krunner

Author

Reply to Cristian

1 year ago

yes the factor is on the receiver
the method described above could possibly transfer that factor VIA FLOW to a new device.

Tommy

Reply to Cristian

1 year ago

It does work. 100% sure. I’ve tested it. Yes the factor is on the watch per sports profile but that’s the weird thing with this V800 bug/feature. Vantage and V800 seem to share this particular data per sports profile

tfk, the5krunner

Author

Reply to Tommy

1 year ago

do you have a view on how long the V800 takes to get a correct calibration factor
I’ve asked Stryd but they don’t necessarily know what the vendors do
Stryd asked polar to copy what they did on the v800 to the vantage.

Jormaperti

Reply to Tommy

1 year ago

Hi Tommy,

I’m glad you were able to test and confirm it. I’m, too, absolutely sure it worked for me. There’s a constant, small but significant change of distances of my routine runs pre and post calibration. They now seem to be very close to those measured by V800 before the Vantage era. Besides that, it seems that the manually set calibration factor has remained in Vantage, i.e. it hasn’t been overrun by the autocalibration feature!

I did a test run yesterday on an official 400 m running track. Did a 10 km run (25 laps) with three watches (yep, I almost felt like being Mr TFK or Mr DCR for a while 😀 ). Vantage+Stryd measured 10.03k, V800 (GPS) was 10.18k, my old ForeRunner (GPS) was, well, off. A lot.

Happy training!

Greg

1 year ago

I don’t quite understand the auto-calibration thing. You should calibrate your measuring device against a well-known (correctly measured) distance. GPS has a greater error than Stryd so if we’re talking about auto-calibration, it should go the other way round.

Soap

Reply to Greg

1 year ago

GPS has a larger error than Stryd if we compare short baselines. Take two 5-meter accuracy GPS positions 20 meters apart and we should expect at most a 50% distance error (assuming random error distribution, but of course GPS error is actually correlated which is why GPS instance pace is bad but not insanely so). Take two 5-meter accuracy GPS positions 2,000 meters apart and we would expect at most a 0.5% error.

Greg

Reply to Soap

1 year ago

Sounds cool. Though only for people who would run 2Ks or more in a straight line. I’m quite sure I never managed to….

Soap

Reply to Greg

1 year ago

It was simply an example of how GPS error need not be larger than Stryd error. Same techniques can be done on courses with minimal turns, or more likely if I were the designer of the system by averaging multiple smaller segments. Remember GPS error, though correlated, is random in its vector, so averaging works very well to cancel out errors.

Greg

Reply to Soap

1 year ago

Vantage especially is known of cutting corners. When you take a look at the lines drawn, you can see they wander though I bet the runners just follow a straight line. Errors along the line of running average out, but errors to the sides add up. So yes, calibration from GPS would be possible, though via observing a strict protocol: straight course, distance measured by the watch between start and stop point etc. Otherwise it looks like de-calibration as Stryd is quite accurate out of the box.

Mirko Surf&Run

1 year ago

In any case I think that the approach of Garmin for his premium watches gives more things to users. Garmin for example in his FR935 or Fenix models gives this choice:
1- “speed from gps or from footpod”
2- “distance from gps or from footpod”
Even if Polar allows the users to set their calibration factors to Stryd or other footpods, maybe it doesn’t give the freedom to choose if the user wants the distance and the speed from footpod or from gps. Probably today and in the future it will function that if a footpod is present, speed and distance come always from footpod. Usually the standard, like also the5krunner advices, is “speed from footpod” and “distance from gps”.
Garmin doesn’t give this option only for the cheaper models (for example the FR35 and maybe the FR235).

-1

Julia

1 year ago

I don‘t know. The Vantage with Stryd and autocalibration is working for me very fine. Last 10k race: 9.99 k. Very bad. 🤪. Last half marathon 21.2. very Bad. My 935 : 10k Race: 10.5 ( autocalibration with Stryd)

Especially the GPS from the garmin devices are much worse than the Vantage