Tacx Vortex Power Accuracy Test

bobones

I recently replaced my Vortex at home with a Neo 2 and noticed that it felt much harder. I compared the output of the Neo 2 with my Vector 3 pedals and it was very consistently 15-20 watts lower. I still use a Vortex in work so thought I'd compare it to the Vector pedals, and I was blown away by how accurately they matched. The Vortex has often gotten a bad reputation, but I always thought it was pretty accurate compared to my PM, and this result seems to back this up.

Here is a comparison of this morning's workout using the DC Rainmaker Analyzer tool. Points of interest - average power within 0.01 watt (!) max power within 5 watts, Mean Max Power graph shows very accurate tracking across power range.

https://analyze.dcrainmaker.com/#/public/45b738b5-c6ec-496c-5d95-dbce2869dfb9

I did have a couple of dropouts on Bluetooth, but they don't really affect the figures. I'd didn't go to any great lengths to calibrate the Vortex other than pumping the tyre up to 100 psi with the tension set from a previous roll down with the Tacx app.

For comparison, here's the Neo 2 v the Vectors. Contrast the Mean Max Power graph showing a fairly consistent and significant difference.

https://analyze.dcrainmaker.com/#/public/fa834e5d-e3ab-406e-6eb9-7dcf6955f815

Of course, without a 3rd known accurate power meter to compare, I can be sure which of the Neo or Vectors is closer to the truth.

dannbodge

Neo is generally the most accurate.
Vortex and Garmin Vectors are notorious for bad power reporting.

Most people see a drop in their FTP/poweer output going from a cheaper trainer to a Neo (it's called the Neo effect)

bobones

dannbodge said:

Neo is generally the most accurate.
Vortex and Garmin Vectors are notorious for bad power reporting.

Most people see a drop in their FTP/poweer output going from a cheaper trainer to a Neo (it's called the Neo effect)

You just seem to be repeating unfounded hearsay: a case of say/read something often enough and it becomes fact?

The Neo forums/groups are full of people complaining about it reading low compared to their power meters, so how is it generally considered the most accurate?

Where is your evidence of the Vectors and Vortex being notoriously bad for power reporting?

Did you look at or understand the charts and stats I posted? If so, you would see that the cheap, wheel-on Vortex trainer did an amazing job of tracking a real dual-sided power meter. Much better than I would have expected, especially given all the negative stuff you read on forums like this one. The Neo also tracks the Vectors incredibly well, just with an offset of -15 to -20 watts, which ties in with the reports of the Neo reading low: the so-called "Neo effect".

I'm just putting it out there that the Vortex is still a great trainer and surprisingly accurate despite what you read on forums. If I'd known what I do now, I wouldn't've bothered "upgrading" to a Neo 2 and spent the near £900 on something else. The only way I'll use my Neo now is with the power numbers being produced by the Vectors, which is a sorry state of affairs given how much it cost.

StillGoing

You're just ignoring the experience of experienced testers. Why do you think the Neo is Shane Miller's go to direct mount trainer when comparing power meters, be they crank or pedal based? Pedal based power will always be slightly higher than power recorded further along the chainline due to drivechain losses. But the Vectors are notoriously inaccurate. That they match the Vortex shows how inaccurate they are.

Oh are you Milemuncher in disguise?

dannbodge

bobones said:

dannbodge said:

Neo is generally the most accurate.
Vortex and Garmin Vectors are notorious for bad power reporting.

Most people see a drop in their FTP/poweer output going from a cheaper trainer to a Neo (it's called the Neo effect)

You just seem to be repeating unfounded hearsay: a case of say/read something often enough and it becomes fact?

The Neo forums/groups are full of people complaining about it reading low compared to their power meters, so how is it generally considered the most accurate?

Where is your evidence of the Vectors and Vortex being notoriously bad for power reporting?

Did you look at or understand the charts and stats I posted? If so, you would see that the cheap, wheel-on Vortex trainer did an amazing job of tracking a real dual-sided power meter. Much better than I would have expected, especially given all the negative stuff you read on forums like this one. The Neo also tracks the Vectors incredibly well, just with an offset of -15 to -20 watts, which ties in with the reports of the Neo reading low: the so-called "Neo effect".

I'm just putting it out there that the Vortex is still a great trainer and surprisingly accurate despite what you read on forums. If I'd known what I do now, I wouldn't've bothered "upgrading" to a Neo 2 and spent the near £900 on something else. The only way I'll use my Neo now is with the power numbers being produced by the Vectors, which is a sorry state of affairs given how much it cost.

Nope. I'm going off my own experience of switching from a Tacx Flux to a Neo and dropping watts (and that's not a cheap trainer either)

My Neo is around 3w different to my Assioma Duos when I'm at threshold so I'm inclined to believe the figures.

There's a lot of reports on various cycling forums and groups about the Vectors being unreliable in their readings.

redvision

The neo and kickr are the most accurate turbo trainers for power.

Most direct drive trainers are more accurate for power than wheel on.

As others have said, vector pedals, even the 3rd gen, are not reliable or consistent*. The assioma pedals are and any differences between them and the neo should be minimal and due to different points of measure.

*Worth noting the vector 4 (or whatever they are to be called) are being announced in the second quarter of 2020 and supposedly address the accuracy issues.

StillGoing

6:52 https://youtu.be/oarGDmFrlZc

Go to trainer for power accuracy and when testing other power meters. He's not paid by TACX.

bobones

That’s a Neo Mk1. There are 3 types Neo and I’m talking about the Neo 2. There are numerous reports of Neo 2 and 2Ts reading low. The mk1 may be the most accurate trainer on God’s earth but that’s not what I’ve been testing.

pblakeney

God forbid that people's egos should be burst! Mine was. Then I realised that it reflected my real life cycling and that my previous turbo was simply massaging my ego.
'tis a hard lesson.

jollygiant

It all means nothing if you can't match the same power and avg speed outside in the real world.

bobones

It’s about having consistent numbers between outdoor rides using a PM and indoor with a turbo. The results in my OP show that I have that in spades with the much maligned Vortex and the Neo 2 is actually a huge backward step in that regard.

redvision

bobones said:

It’s about having consistent numbers between outdoor rides using a PM and indoor with a turbo. The results in my OP show that I have that in spades with the much maligned Vortex and the Neo 2 is actually a huge backward step in that regard.

Training to power outdoors is much harder than indoors due to the nature of outdoor road riding.

Seriously though, if you think your vortex is more accurate than the neo you're fooling yourself.

The neo 2t did have accuracy issues when first launched but these were ironed out. The neo 2 did not suffer the same and along with the kickr is regarded as the most accurate (for power) turbo trainer.

I think the fact that your vortex compares well to your vector pedals says it all tbh.

dannbodge

If you really do think that your Neo has power accuracy issues then get in contact with Tacx/Garmin
They will look through the logs that you send them and determine if there is an issue or not

If there is then they will generally replace or repair the Neo.

Is the firmware on the Neo up to date?

StillGoing

bobones said:

That’s a Neo Mk1. There are 3 types Neo and I’m talking about the Neo 2. There are numerous reports of Neo 2 and 2Ts reading low. The mk1 may be the most accurate trainer on God’s earth but that’s not what I’ve been testing.

So send the log files to TACX who will check it and if faulty, no doubt repair or replace it. It doesn't alter the fact the Vortex is no way more accurate than a non-faulty Neo 1, 2 or 2T. I can't think of a single wheel on trainer that is more accurate than a direct drive one from the same or another manufacturer.

daniel_b

I believe my vortex was over reading by about 10% when I switched to my neo 1 (still going strong after 3 years)

At the end of the day they are only numbers, so to favour one trainer because you believe it is more accurate / matches your pedals, is imo missing the point.

Worst case, just tweak your ftp up / down depending what you are riding.

I look forward to riding the turbo now.
No tyre pressure to check
No roller to engage
No puctures to be had (had one once even with a specific turbo tyre)
The neo is quiet, the vortex is noisy as hell when you wind it up
The neo gives you some left to right movement, and for me the whole riding experience is far more realistic and enjoyable.

Having said that, if you really dislike it that much, they sell well second hand, and am pretty sure I saw the vortex on sale for £200 earlier this year, so maybe flog the neo, buy a brand new vortex, and pocket several hundred pounds towards an upgrade / bike fit / cycling holiday.

dannbodge

Another easy way to check the Neo is to connect it to the Tacx Utility app on your phone. At 90rpm you should be around 150w and 30kph (see below from a Tacx guy).

It might help you determine whether there is a major issue or not

"Yes, in the Tacx Utility App, but you have to take it with a grain of salt. It is a ballpark test designed to exclude serious flaws, and by itself is not especially useful for diagnosing anything. It's very challenging to hold 150w in Tacx Utility App, as there is minimal resistance to inform your pedal stroke.

It may take several minutes of riding to get a consistent result at 90 rpm"

bobones

redvision said:

bobones said:

It’s about having consistent numbers between outdoor rides using a PM and indoor with a turbo.

Training to power outdoors is much harder than indoors due to the nature of outdoor road riding.

I use Xert so training with power outdoors is just as easy as it is indoors. I know very accurately what my threshold power is day to day without having to go through periodic formal testing protocols so it becomes very important that my indoor power meter matches my outdoor power meter to continue to have accurate data and for workouts to be properly matched to my threshold.

redvision said:

Seriously though, if you think your vortex is more accurate than the neo you're fooling yourself.

I don't just "think" this, I measured it. I've tested the devices on an indoor ride and I found the Vortex matches the Vectors much more closely than I could have imagined. Leaving the Neo out of it, the Vectors and Vortex matched on average power for a ride of over an hour to within 0.01 of a watt! That is no doubt a fluky, freaky result on its own, but the rest of the stats and charts show that the Vortex is more that capable of delivering consistent results when compared to a "proper" power meter, and that's what's actually important to me when training with Xert: the absolute power number doesn't matter so much as the 2 devices delivering stats that are comparable. My Neo 2 tracks the power graphs of the other 2 devices very closely so that they're all measuring the same thing, it's just the number produced by the Neo is 15-20 watts less than the other 2 across the board, and that is pretty much useless for training with Xert.

redvision said:

The neo 2t did have accuracy issues when first launched but these were ironed out. The neo 2 did not suffer the same and along with the kickr is regarded as the most accurate (for power) turbo trainer.

I could point you to the Neo owners group on Facebook, or the Garmin forums and you find quite a few people complaining that their Neo 2 produces significantly lower numbers than their other power meters.

redvision said:

I think the fact that your vortex compares well to your vector pedals says it all tbh.

That's a ridiculous comment. If you're prepared to dismiss cold stone facts to support your clearly biased opinions on the Vectors, Vortex and Neo then there is little point in trying to reason with you.

dannbodge said:

If you really do think that your Neo has power accuracy issues then get in contact with Tacx/Garmin
They will look through the logs that you send them and determine if there is an issue or not

If there is then they will generally replace or repair the Neo.

Is the firmware on the Neo up to date?

Yes, the firmware is up to date - I updated it just last week. Don't get me wrong, I like my Neo 2, it's much smoother, quieter and more powerful than the Vortex, but I will be contacting support about its apparent inaccuracy once I have all the facts at my disposal.

daniel_b said:

I believe my vortex was over reading by about 10% when I switched to my neo 1 (still going strong after 3 years)

The difference is that I am not believing anything about the Vortex compared to the Neo 2 or Vectors: I am actually measuring the differences and merely relating the facts.

daniel_b said:

At the end of the day they are only numbers, so to favour one trainer because you believe it is more accurate / matches your pedals, is imo missing the point.

Worst case, just tweak your ftp up / down depending what you are riding.

Sorry, I am not missing any point: if you're training with power indoor and out (which is easy with Xert as I have already said), then a 20 watt difference between your indoor and outdoor power meter is highly significant. This is why I need to use my pedals when on my Neo 2 (in garage at home), and why I can now truly trust the figures produced by my Vortex (in gym at work), which I already had a good deal of faith in.

daniel_b said:

I look forward to riding the turbo now.
No tyre pressure to check
No roller to engage
No puctures to be had (had one once even with a specific turbo tyre)
The neo is quiet, the vortex is noisy as hell when you wind it up
The neo gives you some left to right movement, and for me the whole riding experience is far more realistic and enjoyable.

I totally appreciate all the advantages of the Neo you list, but I still use a Vortex in work so it's not a case of either / or. I will be keeping my Neo 2 but may return it for repair or re-calibration once I can prove that it is indeed as inaccurate as it seems to be. I'll reiterate what I said earlier though: if I knew the Vortex was capable this type of consistency against my Vectors, I would have thought a lot harder about spending £850 on the Neo 2. I have had over 4 years of flawless performance from my 2 Vortexes, but I thought the Neo 2 would be a big upgrade in terms of accuracy, when it turns out, after measuring them, that the Vortexes are actually really pretty decent, whereas the Neo 2 I got sold is consistently under reading.

Let's get this clear. I am not slagging off the Neo in favour of the Vortex. My Neo 2 appears to be inaccurate and I want to get to the bottom of this. A side result is that my Vortex is a lot better at tracking power than I expected it to be.

StillGoing said:

bobones said:

That’s a Neo Mk1. There are 3 types Neo and I’m talking about the Neo 2. There are numerous reports of Neo 2 and 2Ts reading low. The mk1 may be the most accurate trainer on God’s earth but that’s not what I’ve been testing.

So send the log files to TACX who will check it and if faulty, no doubt repair or replace it. It doesn't alter the fact the Vortex is no way more accurate than a non-faulty Neo 1, 2 or 2T. I can't think of a single wheel on trainer that is more accurate than a direct drive one from the same or another manufacturer.

I am not disagreeing with that, but I my results show that the Vortex can be much more accurate/consistent than it's given credit for, and it seems to be much more accurate than my Neo 2. I will send log files if I think it's going to get me a more accurate trainer in return, but from what I've read, people are getting supposedly fixed machines back from Garmin that exhibit just the same or even worse inaccuracy.

Anyway, I now have a 3rd power meter in my possession: a 4iiii precision so I can compare the Neo2, the Vectors, and the 4iiii simultaneously. Here are a couple of comparison runs which show that the Vectors and 4iiii are reasonably close for the most part (within 3%) with the Neo 2 significantly lower. The single sided 4iiii reads a little higher than my Vectors, which ties in with my power balance slightly favouring the left side. The weight of evidence clearly points to my Neo 2 reading low and being well outside its advertised accuracy specification.of +-1%

https://analyze.dcrainmaker.com/#/public/78778d80-bf69-4e03-4ed2-8966f9a5d2c3

https://analyze.dcrainmaker.com/#/public/fd148085-7d9f-4232-7216-121fc7e45d90

The main point of my original post was to demonstrate how accurately the Vortex can track a real power meter and I stand by that. Here's a reminder of that amazing result:

https://analyze.dcrainmaker.com/#/public/45b738b5-c6ec-496c-5d95-dbce2869dfb9

redvision

Your making the assumption that the vortex is more accurate than the neo because the power figures match the vectors.

The vector pedals are notoriously one of the most unreliable and inconsistent power meters. The vector 3 are better but still plagued with inconsistent readings. My vector 3 pedals reported my power to be 20% higher than what it was!

The neo is a proven reliable and accurate trainer.

At the end of the day though believe whatever you want to believe.

pblakeney

The argument appears to be “My 12” rule is bigger than your 12” rule”.
😂😂😂

bobones

redvision said:

Your making the assumption that the vortex is more accurate than the neo because the power figures match the vectors.

The vector pedals are notoriously one of the most unreliable and inconsistent power meters. The vector 3 are better but still plagued with inconsistent readings. My vector 3 pedals reported my power to be 20% higher than what it was!

The neo is a proven reliable and accurate trainer.

At the end of the day though believe whatever you want to believe.

It's not a matter of belief. I am measuring these things for myself and reporting the outcome here.

Did you not notice that I tested these against a 3rd power meter: a 4iiii Precision? This changes the game entirely.

I can now assume that *MY* Neo 2 is inaccurate because it is the odd one out of Vector 3 and 4iii power meters. I am inferring that my Vortex is more accurate than *my* Neo 2 because it matches the Vector pedals, which match the 4iiii PM. This is all entirely reasonable. I am not saying anything about the accuracy of anyone else's Neo!

You are assuming that my Vector 3 pedals must be inaccurate because you read somewhere on the internet that all Vector 3 pedals are flawed and you think your Vector 3s were 20% high. How did you measure that? You'll have seen the Shane Miller tests on Youtube where his Vector 3 pedals line up almost perfectly with his Neo mk1. His Vector pedals must be OK then, but you'll assume mine aren't?

Then you come out with a blanket statement like "The neo is a proven reliable and accurate trainer", which is obviously not true 100% of the time as there are dozens of other reports of them reading low like mine and loads of them are being sent back for re-calibration and repair.

bobones

pblakeney said:

The argument appears to be “My 12” rule is bigger than your 12” rule”.
😂😂😂

Don't be ridiculous. I have posted some measurements on PMs and trainers that I possess and drawn some conclusion that a few people can't seem to handle because they go against the accepted "wisdom" on here.

The mantra is: all Neos are great. All Vectors are rubbish, All wheel on trainers are rubbish.

Can't really argue with the facts though ...

bobones

dannbodge said:

Another easy way to check the Neo is to connect it to the Tacx Utility app on your phone. At 90rpm you should be around 150w and 30kph (see below from a Tacx guy).

It might help you determine whether there is a major issue or not

"Yes, in the Tacx Utility App, but you have to take it with a grain of salt. It is a ballpark test designed to exclude serious flaws, and by itself is not especially useful for diagnosing anything. It's very challenging to hold 150w in Tacx Utility App, as there is minimal resistance to inform your pedal stroke.

It may take several minutes of riding to get a consistent result at 90 rpm"

Thanks for trying to help. I tried this this morning but it didn't really tell me much. I think I was about 25 kph at 90 rpm and 150 w.

I've now tested the Neo against 2 other PMs. The only other thing I can do is independently verify the accuracy of my Vector 3 s using a static weight test, but I am fairly convinced of their accuracy given the fact that they line up with this additional 4iiii power meter.

StillGoing

Of course 4iiii are also notoriously accurate

bobones

StillGoing said:

Of course 4iiii are also notoriously accurate

I'm struggling to find a bad review, and they were good enough for Quick Step and Bora Hansgrohe pro teams, but I'll await your evidence to the contrary.

https://www.dcrainmaker.com/2015/12/4iiii-precision-review.html
https://youtu.be/xnuR4-VgBu8
https://www.cyclingweekly.com/reviews/power-meters-bike-components/4iiii-precision-power-meter
https://titaniumgeek.com/4iiii-precision-power-meter-gen-2-review/
https://road.cc/content/review/205484-4iiii-precision-power-meter
https://youtu.be/RVgjb4W30J0

I really seem to have upset the Neo fan club here

redvision

Where's my post gone?? This new forum has a mind of it's own!

OP, to save further debate, just contact tacx. You clearly believe your neo is reading low and if that's the case it's faulty as the one thing which is proven is the top end trainers are very accurate with power readings.

And FWIW, I'm a wahoo kickr owner, not the neo

StillGoing

bobones said:

StillGoing said:

Of course 4iiii are also notoriously accurate

I'm struggling to find a bad review, and they were good enough for Quick Step and Bora Hansgrohe pro teams, but I'll await your evidence to the contrary.

I really seem to have upset the Neo fan club here

You mean teams that are provided them by their sponsors don't you. Look at any list of the best power meters and 4iiii won't be up there with Quarq, P2M, SRM etc.

You need to catch yourself on. Some of us have had numerous trainers to ultimately arrive at the top end of the trainer tree where it is on the whole problem free and produces the most accurate and reliable data. That could be the Neo, Drivo, Kickr, they're all similar. Some do things differently and a bit extra than the others, like the Kickr will accurately pair with a Wahoo head unit, the Neo won't. The Neo can do road simulation and will allow downhill coasting. etc etc.

Your argument is that a faulty Neo 2T is not as good as your old Vortex. Go figure.

bobones

Look, I dig all the cool things about the Neo, and I've never said the Vector is a better trainer than an accurate Neo, but I've clearly demonstrated that mine reads low. This is not just a belief, I've measured it against 3 other PMs (a left Vector, a right Vector and left 4iiii Precision) and it's significantly lower. Occam's razor says that *my* Neo 2 is faulty, but laughably some people on here cannot accept that, and imply that my Vectors are flawed and the 4iiii is inaccurate to suit their arguments without a shred of evidence in support of their claims. But, I'm the one who needs to catch themself on?

bigmitch41

Maybe just needs calibrating? contact the customer services dept.

bobones

bigmitch41 said:

Maybe just needs calibrating? contact the customer services dept.

Yes, I think so. Looking at the output charts from the 3 PMs, they all track each other pretty well in that the lines remain parallel so they're all OK at recording the power fluctuations. It appears that a simple linear calibration offset would get the wattage numbers to agree.

Here's my Zwift AHDR group ride this morning showing the Vectors and 4iiii within about 6 watts (3%) of each other most of the time, but my Neo 2 is fully 20-30 watts (10-15%) lower.





https://analyze.dcrainmaker.com/#/public/e0fdb223-8199-4217-633b-744dad2e6e8a

StillGoing

bobones said:

Look, I dig all the cool things about the Neo, and I've never said the Vector is a better trainer than an accurate Neo, but I've clearly demonstrated that mine reads low. This is not just a belief, I've measured it against 3 other PMs (a left Vector, a right Vector and left 4iiii Precision) and it's significantly lower. Occam's razor says that *my* Neo 2 is faulty, but laughably some people on here cannot accept that, and imply that my Vectors are flawed and the 4iiii is inaccurate to suit their arguments without a shred of evidence in support of their claims. But, I'm the one who needs to catch themself on?

No you've persistently intimated the Vortex is a better trainer than the Neo. When it's been pointed out that the Neo you have may be faulty and to contact TACX, you're still on here misrepresenting the facts. Just contact TACX and let us know what they say.