Zwift and Garmin Activity time difference

Hi all,

I have just done a 1.5 hour activity on Zwift using my 2T and also recorded the activity on my Edge 530 to do some power analysis.

Starting and ending the two activities within seconds of each other I was shocked to end with a file from the Garmin that is 30 seconds longer.

When you look at the comparisons the time difference between the two traces gets further apart as the activity goes along. It’s like a second on the Edge is shorted than a second on Zwift. Therefore meaning that more seconds pass on the Edge than on Zwift.

be great to hear people’s thoughts.

Steve

0 Luko79 over 4 years ago

Hi Steve, what kind of device do You use for Zwift running? It is a known bug (for me), if the device is a slower one (older IPADs, older ATV or older IOS/Android mobiles or even slow PC) then the time is recorded wrongly into the FIT file due to bad coding (they should give higher priority for accurate 1s (1000ms) recording above graphic priority), if the device is slow then it records 1000ms (1sec) data let say in every 1010ms and in the Zwift's FIT file the duration will be shorter than it happened in reality. (An example: If You upload it to Strava, your segment's time will be 59min30sec depending this file but ingame your segment time was 60min00 for Alpe which is the valid)

The only way to get accurate data is: #1 swap for a faster device #2 record your trainer data with a head unit also (so You need 2 head units, one for trainer and one for the bike powermeter, and the 3rd one is the problematic Zwift device) and those 2 FIT files will have exactly the same length and these will be perfect for dual analisys.

If You have any question, just let me know, i'm an expert in ZwiftPower/Zwift and dual analisys too

0 FTGPMB over 4 years ago in reply to Luko79

I had the same observation as OP and thank you for your explanation. I was using an older iPad for the zwift and a Garmin 520 for the power meter. I actually noticed that time was passing differently in my zwfit world because we were doing a group workout and the start of efforts was starting to move apart! I will try it with zwift on my laptop to see if it improves matters.

0 Luko79 over 4 years ago in reply to FTGPMB

if You have a stronger laptop then that could be a solution (strong gpu is mandatory for fast and stable fps). You can check your device's performance on Zwiftalizer webpage, upload your log(number).txt to there and You will see it .

Yes, unfortunately the Zwift's programmers didnt give higher priority for the accurate timing for recording... (and there are so-so many bugs in that app since years without fix...)