Watts abnormally high when first starting ride.

I have noticed over the last few rides my watts (ANT+ stick reading SRM power data). I will be soft pedaling at 70 to 100w, but the power will read 270-300 on the screen. The head unit reads the real power. If I stop and pull over, or unpair/pair the PM again, it will fix itself. SRM is calibrated and z/o properly. Bike is inside at room temp when starting.

Hi Lauren,

Please submit a support ticket and include the log files of your ride when you can. That would help a bunch. You can find those files in Documents > Zwift > Logs


Sent in log files. Thanks for the help. Also posting under my account and not my wife’s… shared computer oops.

I am noticing the same problem. My SRM head unit is picking up the power accurately, however, it is showing high on Zwift. For instance, if I’m averaging 260watts, its showing up as 310. It’s still fun, but I know it’s illegitimately high when in Watopia…


Hmm. I think we may need to look into this further with regards to SRM.

Is there an answer to this? - I have just finally got my setup with a new pc with suitable graphics card - but using SRM it is as if Zwift is showing 2x the Power. 

I have almost the same problem… but my SRM is Reading higher… and getting worse the longer I ride… I can avg 150W on Zwift but my Garmin display is Reading 220W avg (wich I think is more correct…)  on my first intervall I did read a bit low… but not that much… both is using the same SRM Power meter With ANT+


I have the same problem as Torleif. The watts reported from my SRM to my head unit (Garmin Edge 500) on my bike are 10 to 20% higher (the difference gets larger the higher the wattage) than on Zwift. I’ve tried callibrating with my head unit. Doesn’t seem to help. Very curious if you have any recommendations.