Guys, a lot of discussion on calibration of the powermeter and the ability to do this yourself.
This might be interesting for just a small group of people, but for most people a powermeter should just do its job. It should be flawless, easy to install, easy to maintain, reliable and accurate (in a certain window). But for me, just a cyclist, it should be accurate between rides over a longer period and used as a training aid. I do not have another powermeter and therefore, what does it mean if my powermeter is 2% off compaired to another one? For me it is okay if the powermeter shows 300Watt instead of 306Watt as long as it shows these values all the time. With this I can use it as a training aid to improve my overall performance.
Giving the possibility to change/adjust these powermeter yourself might also introduce a lot of problems by people not exactly knowing what they are doing and also giving P2M a bad name, because it are always these people who start complaining.
Just my 2 cents.
High accuracy may not be important for your particular use case, but it is necessary for lots of scenarios. An inaccurate PM is useless for aero testing, for instance, as well as tracking power across multiple power meters / bikes.
I've never heard of problems with SRMs or Quarqs related to people changing the slope. You can always revert to the original slope that came with your power meter. power2max prints it on a certificate, Quarq prints it on a slip of paper, and SRM puts it on a sticker on the back of the power meter itself. It's not that big of a deal.
Static torque testing has been the de factor standard for testing power meter accuracy since power meters first started being used. SRM, Quarq, et al. are all open about using it verify the accuracy of their units. Quarq has a video tutorial on how to use Qalvin to do a static torque test - https://www.youtube.com/watch?v=4IZL3QXtYv0
. Garmin Vector also has a section in their manual describing how to perform a static torque test to verify calibration. I don't remember where I read it, but I believe the forthcoming 4iiii's calibration procedure also involves a static torque test.
So I'm a bit surprised we're even having this discussion.
If the slope on a power2max was adjustable, then it would all be a moot point. Because at the end of the day I shouldn't really care what power2max's position on static torque testing is - I just want my device to be properly calibrated and to be able to verify it's working properly. If I want to use static torque testing to verify the accuracy of my power2max unit, that's fine. If I don't care either way and trust power2max, that's fine. If I want to use some other verification method, great.
But if I have to send my unit in to be re-calibrated, then that's when I do care what their views on calibration are.