Originally Posted by kfried

I use a Stages L-only power meter and I did calibrate it before each ride. It is still really hard to get an accurate comparison in terms of speed because the very first day with my new bike, my speed sensor battery died. That's now been replaced, and the early conclusion seems to be that those extra watts for the same heart rate were a combination of new bike exuberance and the 10 days off the bike leading up to building/riding the new frameset. I've been out the past few days and my power output per given heart rate seems to have returned mostly to the previous range.