The accurate power reading rabbit hole is real! I upgraded my trainer from a Flux S to a Neo 2T. I also have a stages L sided power meter. I was using the stages and flux together with powermatch. I want to use the Neo 2T without powermatch to simplify my setup and I am not concerned about getting the same exact numbers outside.
First ride on the new trainer was today and I recorded power from the stages and the neo for comparison. The results were not as close as I was expecting. I used the zwift power analyzer tool to compare the .fit files. See screenshot below. The difference was around 15 watts with the Stages reading higher than the Neo. The Neo does estimate L/R balance and says I have a 52/48 L dominance.
I think I will have to borrow a third source of power recording to see which one is correct but I think the Neo is a better source of power reading. Is anyone else experiencing similar results?
Drivetrain loss?
I don’t get the point in worrying about it. How will it change your training? Pick one and be consistent in it’s usage.
Drivetrain loss probably contributes. I did not test specifically for this but I did cross chain intentionally for short periods in another workout and I it looked like the delta in power between the two grew by a couple more watts.
There might not be reason to worry about but I do.
Given that my Neo 2T struggles to measure cadence at all accurately even when I’m pedalling steadily at constant power, I’d be suspicious of the accuracy of any left/right dynamics.
I have a Neo 2 and 4iiii L PM. I’ve always used power match, that’s what I’m using outside so figure it should be consistent when on the trainer also.
The rabbit hole gets even deeper if you test the results in different gears / at different flywheel speeds. (Also might try Erg vs resistance vs sim mode).
If you really want to dig deeper, here is a very good read:
https://tacxfaqx.com/knowledge-base/linearity-showdown/
This is pretty much a non existent problem with the Neo2T.
Been there. Done that.
This is a Stages G3 left set to 165mm vs a Neo 2. 175mm actual length on the Stages.
I don’t really care what my numbers are. This gets me close enough for training purposes.
I’d say go with the Neo 2T and base your training off of that. Stages isn’t a very reliable source imho. And it’s not possible to calibrate the Neo. If you were to purchase a 4iiii or Quarq or another pwoermeter that has the option of setting an offset then you’re golden. Just offset it to match the Neo. 