Indoor Vs Outdoor FTP

I’ve been involved in this thread since it’s inception and nobody has come up with a proven reason. I have the same problem. Lower power and HR indoors and increased RPE. Have tried so many things, none solving the problem. Main reason why I prefer to do workouts outside. My latest opinion is that I’m not using my upper body indoors, so HR doesn’t need to be as high and the upper body does contribute to power, so power indoors is lower. I thought it was temperature related at one time, but I’ve tested that may times and it didn’t make a difference for me.

I even purchased an Inside Ride to test the upper body theory. But the movement on that wasn’t what I expected and actually made RPE worse. Actually looking to sell it. (At no fault of Inside Ride)

So keep asking the questions. I’m paying attention closely for any other ideas.