What to do when switching power meters?

Hi Armando! For the last 4 months or so, I’ve been using a Stages left-only PM on my primary training bike. So a lot of the Xert data is based on the readings from this device. As of this weekend, I’m testing a Pioneer dual leg PM. Looking at the data, I believe that Stages my have overestimated my actual power output, relative to the Pioneer. We could debate calibration, etc. but I’m riding faster up the same hill now with power numbers lower than with Stages, and with the same bike/rider weight and ambient conditions (actually hotter now, too!).
So the end result is that I am riding harder or as hard as before, but because of the lower readings, the XSS are lower and impact on MPA is lower as well. Are there any solutions to this issue, while preserving past data?

I’m looking for a solution to this as well as I have 6 months of data from a Smart trainer and 1 month or data from a powertap G3 I recently bought. The difference between the two is around 8-10%, I wish there was an easy way to % down a large subset of power data so it can be uploaded and essentially “normalized” with the new PM.

The easiest solution is to open the Activity Details page for the first activity you have with your new power meter and using the Advanced tab, adjust your Fitness Signature parameters down but what you feel would be correct and then Save/Lock that signature to the activity. That activity and all subsequent ones will reflect the change.

I used this advice and meticulously fixed the difference between these two powermeters, will use powermatch in the future!

Thank you, Armando. Should I adjust the Threshold power, or all the parameters?

The change in power meters will likely affect all three. For starters, I would suggest adjusting each by the same percentage.