Built it up yesterday, very easy.
It seems to consistently read around 5% lower than my Tacx Neo 2t.
So for the next ride I’ll be trying to adjust the Magenes power scaling and let’s see.
The weight penalty compared to the latest Ultegra 12s was 70g on 170mm cranks and 50/34 for the ww’s.
Update on the accuracy: In short, I'm very happy about it.
After some test runs,
average power and normalized power are on average
only 0.4-0.6% (!) off from my Tacx Neo 2t wih a 104% power slope setting.
I found that the reason for the larger differences I previously experienced stem from the varying temperature in my workout room. The PM was always correctly zero'd. By having a +- constant room temperature the previous inaccuracies were greatly reduced as I found.
But that's not the full story, there's 2 more things to consider:
1. Eventhough the average power is basically identical to my indoor trainer, the actual power data is not always as close as the average would insinuate.
Actually, the Magene is often surprisingly above or below the tacx ("outliers"). The attached screenshot shows this nicely, where the blue line is the Magene and the purple line the Tacx.
2. The max power, is still off a bit, I think DCRainmaker noted the same thing. In my case it's still 6-7% in difference. Also, the 1s critical power is off by the same percentage, while all other CP value differences are negligible.
All in all a fantastic product and I'm wondering whether I can use it again for my upcoming gravel build. Maybe this time with a lighter 1by crankset as some have done here already.
