Someone here is auditioning for a job doing smart trainer technical support 
Also, note how all of DCRâs and GPLamaâs reviews show the trainers are consistently 2-5% lower than the comparison power meters. /s
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I donât really see the problem. If you have a separate power meter on your bike you should be using that as a power source anyway so your inside and outside numbers match.
I am a happy camper with my Neo 2T so far. The power readings seem to be super consistent for me, which is what really matters and aIlows me to train properly.
I donât have an external power meter yet, but I am looking forward to my free 20W FTP bump, should I ever get one.
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for what itâs worth, i have a 2t and dual sided assiomas. same problem as you. 20w less at 300w. iâd say it averages around 8-10% less.
you donât see the problem that a person needs a second power meter to make their $1400 trainer accurate? ok.
I donât think that the mean max graphs are all that interesting when comparing two different measuring devices, and certainly not the main thing I care about. With the mean max graph, we donât even know if the â10 minuteâ max power is even over the same interval or not.
What I care about, and what I think what others care about, is âfor a given intervalâ, do my power meters agree. Average power is the way to do this. This matters for things like âwhat was my power up that climbâ, or âwhat was my power during my 20 minute FTP testâ, or 'what was my power during the last minute of my FTP ramp test.
For the Neo 2t (DC Rainmaker Analyzer) for the entire ride:
Dzero: 246.20 watts
Powertap P2: 243.19 watts
Neo2t: 240.56
The neo2t was 2.3%lower than the dzero over the entire ride, and closer to the P2s. Looking at several sections the error was fairly consistent in the 2-3% range to the Dzero, and less to the P2s.
Results from the original neo were generally slightly better, although the SRM pedals used in that test seem way off. DC Rainmaker Analyzer
If people are seeing 20 watts low at 300 watts (ie a 6.7% error), I donât think this is âexpectedâ, or inline with review results. Yes, if you have a horribly maintained drivetrain, you will see higher losses than if it is in reasonable shape. People who are spending for power meters and high end smart trainers, and are detail oriented enough to compare them likely have at least decently maintained drivetrains.
Having dealt with smart trainer inaccuracy issues and customer support for my trainer and a friends, it is absolutely amazing at what customer support thinks is normal and acceptable. Trainers that are 10-15% off from 3 other powermeters are just fine, and itâs the power meters that are wrong.
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Iâve done countless dual analysis with different powermeters and the Neo 1 and 2T. At the end of the day, the same conclusion has been reached - the 2T reports power lower than any of the powermeters used and the Neo 1.
Whatâs interesting is that flywheel speed seems to really matter. At lower flywheel speeds the Neo 2T begins to read closer to whatever powermeter Iâm comparing it to.
Whilst the discrepancy doesnât matter for many, at the top end of eRacing where you must connect your trainer as the primary powersource to Zwift, a difference of 4% is hugely significant. Whilst probably within the accepted tolerance for the manufacturer, weâre getting into the situation that trainers are being required to be absolutely precise and accurate, and used in ways that they were never designed.
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Iâve seen this kind of thing with ERG before, and I think the problem is with Zwift and ERG rather than the Neo or powermeter. Iâve linked a dual recoding I did with my OG Neo and old Powertap P1S pedals. This was a workout I imported to Zwift from Xert. Notice how the power reading on the pedals ramps down during the work interval, but the Neo reports a consistent power.
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So I did get a pair of Assiomas recently and so far I am happy to report that they track quite closely to my Neo2T (so no big FTP bump for meâŚ). I have done three TR workouts with dual tracking.
Pallisade (interval):
Neo2T: Avg 282W ( -1,5% )
Duos: Avg 286W
Mills:
Neo2T: Avg 194W (+1,2 %), NP 245W (-1,4%)
Duos: Avg 192W, NP 249W
(about 7W seperation at ~320W, so 2,3%)
Jepson:
Neo2T: Avg 211W (-0,5%), NP 241W (-1,6%)
Duos: Avg 212W, NP 245W)
After a hard effort on a local climb, intervals.icu gave an eFTP of 278W with the Assiomas and my last ramp test with the Neo2T gave me 279W.
Both devices show a L/R power distribution of 50%/50%
In conclusion, I cannot really confirm the bad rep the Neo2T seems to get on forums in this regard and I am happy with both purchases 
Although I guess for people with FTP north of 350W the difference could become substantial.
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As a Tacx owner, and a background in science (where measurement matters), this is one of the silliest threads Iâve ever seen.
The real answer is none of them are technically correct and the answer that makes the most sense is to use the power measurement you use outside for inside (ie: the crank or pedals).
As for eSports, youâre not after âcorrect powerâ, just the one that inflates your numbers the most. That will likely be some kind of single leg crank arm meter only. If you have to use the trainer, find the one that reads highest. If youâre really a baller, you buy 5 of the same âhighest model/ brandâ at a time and test all to see which of them reads even the highest. People do this with engines in stock / spec classes all the time, spending tens of thousands of dollars and keeping the one that only makes 1-3hp more.
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As a consumer Iâd love to get my moneyâs worth though. And for $1400 itâs not unreasonable to want a more accurate power meter than what 2T offers. Iâm not even arguing everybodyâs 2T is reading wrong but thereâs a HUGE chunk of people who noticed the discrepancy.
At the end of the day, sure, I use my power meter to drive Neo. But why did I pay $1400 then?
What if I wanna use a cheapo bike on my trainer with no power meter and trust that 2T measures very close with my quarq or favoro assiomas on the other bike.
Anyway⌠I gave up long time ago. Only want to share my experience so that the next âsuckerâ might make a better decision than I have. I wish I bought the original NEO when I had the chance.
âA background in scienceâ. Lol. I too, believe in science.
Thank goodness you have the real answer that addresses none of the concerns.
The whole thing is just about equipment working as expected. Some 2Ts donât work as expected. We know this because we compare them to the way we measure power outside and/or other trainers. Itâs not about chasing a trainer for the best esports numbers. Come on.
Much like @Wirt, Iâve found my workaround. But that doesnât change the frustration of spending a large chunk of change on something on something that is wonky, but not quite wonky enough to get Tacx to care.
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