Tacx NEO 2 power accuracy

I’m in talks with Garmin now for a solution. Had to send them data and do a test now I’ve sent them my receipt. Pending a reply. Literally bought the trainer as they advertised most accurate on the market, so I went straight to the top. If they solve the issue I’ll be happy and will continue with Garmin products.

RMA procedure and replace by Garmin. Btw one of my friend has a 2T and he has 10- 18% overreporting! (depending on flywheel speed, with 0.0.38fw, comparing to a reliable and accurate Power2Max)... i dont know how could they miscalibrate these units in the factory, from original Neo1 there were minimal (or none) faulty calibrated, but from the Neo2 and 2T have "tons" in both ways... (of course, if it shows higher value that is good for the EGO and users dont complain too much  )

I'm now on my second Neo 2, my fourth Neo in total. This Neo 2 is better for accuracy than the previous one for averaged power, reading around 5% below my Assioma Duos at cruising power. Its predecessor showed a deficit of 7-8% across all power levels. 

However, the new one (refurbished warranty replacement) appears to be very bad at responding to peak power, with 15% lost from the maximum today. But I do not have extensive data for comparison. This is just one data point from today's ride. 

Here is some data for my power curve over 60 minutes from a 90 minute ride today.

I can live with the -5% for daily training and social rides, but it makes racing on Zwift a bit disenchanting, so I've given up racing. 

@eezytiger 1s peak power difference is not an issue, You can experience (almost) such a difference if You record the SAME power source with 2 head units due to the 4 or 8HZ data transfer (but the recording has only 1s resolutin  and averaged. ). Nobody will win a race with an 1s +40w difference in Zwift :) 

The problem in your comparison is the rest of part of the CP curve, are You using your Duos via ANT+? both pedals are checked with known weight that they are absolute accurate? (how is your balance, 50-50?). This 5% difference is huge, should be 1-2% maximum (except on 1-5s interval)

But here is an example about the 1s peak "problem", You need to analize the full chart , i think it´s clear why it is not a problem :) 

I'm not bothered about the peak on its own. It is the largely consistent 5% deficit overall. As I posted earlier in this thread my previous Neo 2 was -8%. That's when I gave up racing on Zwift and I haven't resumed since receiving the new trainer. 

Remember I also had two Neo 1 trainers. I was able to compare the second of those with my pedals and they matched within +/- 1% at all power levels, so no penalty at all from the Neo 1. By feel and heart rate vs power at steady state (say 200W erg) the original Neo also matched the second Neo.

So that's two Neo 1 trainers matching each other and matching the pedals, and two Neo 2 trainers under reporting power by 5-8%.

Also, not that it has anything to do with the trainers, at 58 years I can ill afford to be robbed of 5% of my power, never mind 8%. That's not something I can easily make up after over five years on Zwift. So, for now at least, I no longer race on Zwift. 

Yes, yes, now i remember, then You should send back this refurbished Neo2 also, it is not accurate. (just working :) )

Has anyone got anywhere on this with Garmin? 

I had a Neo 2 as a warranty replacement. I thought the 10% power loss was my own fitness (suspected long covid etc.). After lockdown I got some help from a friend who proved that the Neo 2 was 8-10% below using multiple power meters reading consistently with a Wahoo KickR (so don't blame the bike). All evidence sent to Garmin - including the Wahoo KickR reading the same output as the PM within 0.2%

Garmin sent me another Neo 2 refurbished replacement and it's the same 8-10% below.

Garmin are arguing that this is "well within" the margins ...duh, advertised as within +/- 1%

I've nowhere left to go, other than ebay the damn Tacx and pass the problem on to someone else :-(

Show them this page, where accuracy for the Neo 2 is claimed to be better than 1%.

https://buy.garmin.com/en-GB/GB/p/690886#specs

If there is any additional reason for complaint, such as unacceptable noise then use that as a reason for exchange.

Thanks eezytiger, but I've done that and they are still arguing that 8% is within a 1% margin. I've told them it's embarrassing that they would claim this. They are suggesting it's drive train losses.

Four different power meters, two different bikes, checked against a Wahoo KickR. Everything is consistent apart from the Tacx Neo 2.