FW 13.21: VO2Max isn't changing

Same thing happened to me. 945 to 955 I lost a couple of points right away then it stabilized.

Look at how clearly the VO2Max algorithm changed between 945 and 955. 945 had a lot more day to day variation and was maybe too optimistic. 955 was slowly stabilizing until I got injured and stopped running, temporarily. This is a graph from runalyze.

Guys, you are talking about different algorithms between different models but the issue I have is 955 specific. Using this watch only, my fitness has improved (pace during my easy and threshold runs), watch says my predicted 5k times have now gone down from 25:30 to 23:13 in the last 2 months or so and VO2 max still shows the same value as 2 months ago - 46. I’m fine with algorithm changes but to go from 25:30 to 23:13 in 5k and have the same projected VO2Max is just plain wrong. 

I feel like the main advantage of 955 over AWU now is all the analytics Garmin watch(es) do behind the scenes. If these are inaccurate there is very little reason to stick with Garmin atm.

Have you uploaded the data into Runalyze to see how it moves in the decimals. Unfortunately Garmin only reports the full digits but the .fir file contains the results to two decimals. I did submit and idea request to Garmin on this matter also.  There was also an algorithm change in the predicted race times in one of the recent FW updates that realigned mine projected times also.

Where do you get that report with two decimals displayed on the axis? Thanks

Dude, you keep asking about Runalyze and decimals. I don’t use Runalyze and am not planning on using it either. Also I don’t care about decimals in this case. 25:30 to 23:13 is more than a decimal change.

tools-->trend analysis-->select running (or cycling) only as sport-->add plot-->in value select "vo2max estimate"

Understood , but it's actually a very nice too and useful in my opinion.  And the granularity of the information is much better. I only came about it when this issue raised its head and I decided to look into it. Of course it would be nice if the Garmin App and Web also did all this analysis but unfortunately they don't.

Here's my vo2max. Not a single change in the last 6 months! This is totally unrealistic, as I can now run 20 sek/km slower at the same effort than 3 months ago. Runalyze can clearly capture it, but Garmin  has fallen asleep. Working as intended ...