Power Lower on the turbo than on the road

Hi iv been riding Zwift for awhile now and iv have noticed that my Garmin Vector 2s petals read about 50 Watts lower on the turbo than on the road. I calibrate the using my garmin before I ride on Zwift but this doesn’t seem to help. Does anyone know whats going on or how to fix this problem? Thanks

How are you comparing the 2 rides? 

Watts are watts and should not matter if it’s on a trainer or on the road.

Are you running the Garmin head unit at the same time as Zwift to see if the numbers are reporting similarly?



The Zwift ride page is showing 10-20% less power and cadence than my Garmin 810 head unit. Also the speed and distance covered is far less!

I should have said thats on my rollers so going to see how turbo compares next time?


Are you comparing the rides using the same power meter on the road as you are using within Zwift? If not the difference can be attributed to not having the rollers/trainer calibrated correctly or that you are not using a power meter at all on the roads and are just getting an estimate.

You cannot and should not compare speed and distance within Zwift to what you are seeing on your Garmin, the Garmin knows nothing about the elevation changes within Zwift.

Ah ok I didn’t think about the Garmin not taking hills etc into account? I am using my Vector Pedals power meter and always calibrate them before each ride. They are showing more power on the Garmin than the Zwift page during rides.