Quick question I have a single sided 4iii 105 crank based power meter, now this was working fine in TR but on apps like Strava and Cyclemeter was reporting x2 the power output on my display to resolve this on the 4iii app I had to select 3rd party compatibility now the power meter works fine when out on the road with said apps and displays correct power.
When these rides are sync’d with trainer road they now show 1/2 the average power compared to say strava so 1/2 the correct average power, whats going on? to note I have not yet done a TR session with the 3rd party app option selected so I am not sure how TR will display power using the app.
From my understanding the 3rd party compatibility only makes sense when using a dual sided PM. From the 4iii manual:
By default your powermeter adheres to the Bluetooth Smart standard and transmits power data from each leg to a Bluetooth Smart display unit independently. Some Bluetooth Smart display units and apps do not support this. You can enable third-party compatibility mode through the 4iiii App. With this option enabled your powermeter will combine the power data from both legs for the display unit or app.
So when you enable this feature on a single side PM it reports the left power + zero from the other leg (instead of doubling) so everything is fine with TR IMHO, but I may be wrong.