New trainer setup, different zpower

I have a Road Machine trainer and was mounting my main road bike 52/36 11-28 700x25c wheels and my zPower matched a Stages power meter.

Switched my bikes to a 50/34 11-32 700x30c wheels and my power output plummeted to about 40 watts less overall.

I’m at a loss as to why my power output plummeted from one day to the next.

(Updated my cadence sensor setting in Zwift to 700x32 from 700x25 wheel and same results.)

Any help/suggestions are greatly appreciated!

My guess is that since you have different gear ratios you will have to have higher cadence on the new bike (50/34) to generate the same amount of power/speed.

Did you calibrate the trainer (if possible) before the rides?

Thanks for the replies. But, it looks like the issue was that I needed to do one full turn of the tension knob (not two full turns despite what the manufacturer recommends).