Stages Gen 3 vs Tacx Neo waaaay off

A light bike doesn't replace good fitness.

Moderator: Moderator Team

spdntrxi
Posts: 3540
Joined: Sat Jul 20, 2013 6:11 pm

by spdntrxi

stages is better then 5%... claimed <1.5 I bet it's better then 2% for sure. People always shit on stages but it's actually a solid PM other then the glaring one-side issue. Would it be my first choice?...NO.. would I use it for sprint training? NO.. but I'd say most stuff between 100w-1000w its more then good enough.

by Weenie


AeroObsessive
Posts: 78
Joined: Wed Dec 12, 2018 7:42 am

by AeroObsessive

spdntrxi wrote:
Thu Feb 13, 2020 5:23 am
stages is better then 5%... claimed <1.5 I bet it's better then 2% for sure. People always shit on stages but it's actually a solid PM other then the glaring one-side issue. Would it be my first choice?...NO.. would I use it for sprint training? NO.. but I'd say most stuff between 100w-1000w its more then good enough.
It could have 0.05% accuracy, single sided power meters are simply a waste of time. Full stop. Humans are asymmetrical, unless you can quantify that variance at any given moment, the data merely tells you how hard one leg is working.

There are enough dual sided power meters now that single sided power meters should go the way of the dinosaur.

cdncyclist
Posts: 90
Joined: Wed Feb 17, 2016 12:10 am

by cdncyclist

AeroObsessive wrote:
Thu Feb 13, 2020 10:20 am
spdntrxi wrote:
Thu Feb 13, 2020 5:23 am
stages is better then 5%... claimed <1.5 I bet it's better then 2% for sure. People always shit on stages but it's actually a solid PM other then the glaring one-side issue. Would it be my first choice?...NO.. would I use it for sprint training? NO.. but I'd say most stuff between 100w-1000w its more then good enough.
It could have 0.05% accuracy, single sided power meters are simply a waste of time. Full stop. Humans are asymmetrical, unless you can quantify that variance at any given moment, the data merely tells you how hard one leg is working.

There are enough dual sided power meters now that single sided power meters should go the way of the dinosaur.
I won't disagree that dual sided may pick up assymettry, but what should one do with that information?

I would really love to see evidence or data that a dual sided powermeter used to inform power based training leads to better outcomes and perfomance than single sided. Do you have any to share?

AeroObsessive
Posts: 78
Joined: Wed Dec 12, 2018 7:42 am

by AeroObsessive

cdncyclist wrote:
Thu Feb 13, 2020 4:45 pm
AeroObsessive wrote:
Thu Feb 13, 2020 10:20 am
spdntrxi wrote:
Thu Feb 13, 2020 5:23 am
stages is better then 5%... claimed <1.5 I bet it's better then 2% for sure. People always shit on stages but it's actually a solid PM other then the glaring one-side issue. Would it be my first choice?...NO.. would I use it for sprint training? NO.. but I'd say most stuff between 100w-1000w its more then good enough.
It could have 0.05% accuracy, single sided power meters are simply a waste of time. Full stop. Humans are asymmetrical, unless you can quantify that variance at any given moment, the data merely tells you how hard one leg is working.

There are enough dual sided power meters now that single sided power meters should go the way of the dinosaur.
I won't disagree that dual sided may pick up assymettry, but what should one do with that information?

I would really love to see evidence or data that a dual sided powermeter used to inform power based training leads to better outcomes and perfomance than single sided. Do you have any to share?
Hopefully these links work.

The key thing about the pedalling asymmetry is that it is not a constant, it has been seen to fluctuate depending on intensity.

The statistical significance of the variance is usually pretty minor, but as the saying goes, it's not a problem unless it's a problem. If the variance is not causing undue biomechanical issues then it's all good. And sometimes, trying to arbitrarily "correct" the L/R balance can cause more issues than it supposedly solves.

So to Stages. The whole point of power meters is to get good, accurate and precise data of effort. Acutely, and longitudinal. If your power meter, because it measure one side only, and because of its own precision and natural human asymmetry means that your data could be totes accurate, or easily up to 10% or more higher or lower. To put that in numbers, imagine doing a 300 watts effort, but your Stage is only saying 270, or 330. That's a *massive* amount of unknown. MASSIVE.

Your dual sided power meter does not need to break down L/R balance, but at least it will give you a better picture of actual effort.

https://www.google.com/url?sa=t&source= ... 1621689870


https://www.google.com/url?sa=t&source= ... CMNK_H0axc

cdncyclist
Posts: 90
Joined: Wed Feb 17, 2016 12:10 am

by cdncyclist

AeroObsessive wrote:
Thu Feb 13, 2020 8:37 pm
cdncyclist wrote:
Thu Feb 13, 2020 4:45 pm
AeroObsessive wrote:
Thu Feb 13, 2020 10:20 am
spdntrxi wrote:
Thu Feb 13, 2020 5:23 am
stages is better then 5%... claimed <1.5 I bet it's better then 2% for sure. People always shit on stages but it's actually a solid PM other then the glaring one-side issue. Would it be my first choice?...NO.. would I use it for sprint training? NO.. but I'd say most stuff between 100w-1000w its more then good enough.
It could have 0.05% accuracy, single sided power meters are simply a waste of time. Full stop. Humans are asymmetrical, unless you can quantify that variance at any given moment, the data merely tells you how hard one leg is working.

There are enough dual sided power meters now that single sided power meters should go the way of the dinosaur.
I won't disagree that dual sided may pick up assymettry, but what should one do with that information?

I would really love to see evidence or data that a dual sided powermeter used to inform power based training leads to better outcomes and perfomance than single sided. Do you have any to share?
Hopefully these links work.

The key thing about the pedalling asymmetry is that it is not a constant, it has been seen to fluctuate depending on intensity.

The statistical significance of the variance is usually pretty minor, but as the saying goes, it's not a problem unless it's a problem. If the variance is not causing undue biomechanical issues then it's all good. And sometimes, trying to arbitrarily "correct" the L/R balance can cause more issues than it supposedly solves.

So to Stages. The whole point of power meters is to get good, accurate and precise data of effort. Acutely, and longitudinal. If your power meter, because it measure one side only, and because of its own precision and natural human asymmetry means that your data could be totes accurate, or easily up to 10% or more higher or lower. To put that in numbers, imagine doing a 300 watts effort, but your Stage is only saying 270, or 330. That's a *massive* amount of unknown. MASSIVE.

Your dual sided power meter does not need to break down L/R balance, but at least it will give you a better picture of actual effort.

https://www.google.com/url?sa=t&source= ... 1621689870


https://www.google.com/url?sa=t&source= ... CMNK_H0axc
Sorry if I am derailing this thread. I think we are talking about 2 different things. No debate that assymetry exists, and that single sided might not be accurate. But for training, it seems to me that precision, not accuracy, is more important. I disagree with the assertion that the whole point is to get 'data of effort' - the whole point is to be able to guide training to improve performance.

While I only read the abstracts, the first article is descriptive and speculative with respect to assymetry and injury. The second concludes with "applying large forces on the pedals and balancing pedal force application between the dominant and non-dominant limbs did not lead to better performance in this cycling time trial"

AeroObsessive
Posts: 78
Joined: Wed Dec 12, 2018 7:42 am

by AeroObsessive

The data contained in the studies show that the variance between left and right varies with effort. Hence any notion of precision with a single sided power meter is notional. At best.

TribesMan
Posts: 2
Joined: Sat Oct 19, 2019 5:51 pm

by TribesMan

When I first started using power meter, I was 100% sure there was something wrong with it. :D
My average L/R balance was 44/56 on most of the rides.
Considering I don't have history of any injuries, and from what I read online I was sure my balance should be below 48/52.
I did all kinds of tests and checks with weights, but all results I got from the power meter were spot on.

After riding for a month and analysing the data further I found out that this also varies massively depending on my cadence and power output.
At low cadence (75-80rpm) and high load (>90% FTP) it could be close to 49/51. At high cadence (95+rpm) and low load (<60% FTP) it can be even 38/62.

So yeah, in my case I guess trainig with left only power meter would not be the best choice...

AeroObsessive
Posts: 78
Joined: Wed Dec 12, 2018 7:42 am

by AeroObsessive

^ your experiences here are amazingly normal, in terms of the changing L/R outputs at different cadences/power.

And this is the point I am doggedly banging on about, you don't know if you don't know.

In the application of training - due to the above mentioned variations in L/R balance, accuracy and precision of the power meter in question, a 30 watt variance or more is highly probable. This makes it a worthless training tool.

If an athlete came to me with a Stages and a HR monitor I would not prescribed any power based training, HR would be a more reliable metric in this case. And I think most know my stance on HR.

cdncyclist
Posts: 90
Joined: Wed Feb 17, 2016 12:10 am

by cdncyclist

AeroObsessive wrote:
Fri Feb 14, 2020 9:55 pm
^ your experiences here are amazingly normal, in terms of the changing L/R outputs at different cadences/power.

And this is the point I am doggedly banging on about, you don't know if you don't know.

In the application of training - due to the above mentioned variations in L/R balance, accuracy and precision of the power meter in question, a 30 watt variance or more is highly probable. This makes it a worthless training tool.

If an athlete came to me with a Stages and a HR monitor I would not prescribed any power based training, HR would be a more reliable metric in this case. And I think most know my stance on HR.
I concede you may have a point for some people (although still lacking performance data - again the article you provided specifically stated there was no difference in performance). To declare no power is better than single sided (for most people) I find a little outrageoues - and contradictory to many others experience (including mine - I started with single sided and went to double and find no appreciable difference) from not training with power to training with power. But I won't argue, you have provided your rationale, I will wait for better evidence.

spdntrxi
Posts: 3540
Joined: Sat Jul 20, 2013 6:11 pm

by spdntrxi

I started with powertap and crank based.... went dual pedal.. and now have multiple dual pedal and multiple left crank only.
My numbers are solid and repeatable for my useage... I have no issues with stages and other 1 arm PM's I have tried.

AeroObsessive
Posts: 78
Joined: Wed Dec 12, 2018 7:42 am

by AeroObsessive

cdncyclist wrote:
Fri Feb 14, 2020 10:54 pm
AeroObsessive wrote:
Fri Feb 14, 2020 9:55 pm
^ your experiences here are amazingly normal, in terms of the changing L/R outputs at different cadences/power.

And this is the point I am doggedly banging on about, you don't know if you don't know.

In the application of training - due to the above mentioned variations in L/R balance, accuracy and precision of the power meter in question, a 30 watt variance or more is highly probable. This makes it a worthless training tool.

If an athlete came to me with a Stages and a HR monitor I would not prescribed any power based training, HR would be a more reliable metric in this case. And I think most know my stance on HR.
I concede you may have a point for some people (although still lacking performance data - again the article you provided specifically stated there was no difference in performance). To declare no power is better than single sided (for most people) I find a little outrageoues - and contradictory to many others experience (including mine - I started with single sided and went to double and find no appreciable difference) from not training with power to training with power. But I won't argue, you have provided your rationale, I will wait for better evidence.
Why would there be any effect on performance? The variance of L/R output is perfectly normal. Where the variance of L/R output would cause issues is with the Stages (and other single sided power meters) readings in relation to collection of data and subsequent utilisation of of power readings for training purposes. Maybe y'all have bigger tanks than me, but a variation of 20-30watts (for example) is rather large for a prescribed effort.

As for your anecdote - some people may have perfect 50/50 balance regardless of power output or cadence. But, again, you have no way of knowing that unless verified by another source.

I may be wrong, but I am going to guess you have not performed any direct comparison of your power meters and efforts to accurately state there was no statistically significant variance.

You don't know what you don't know.

spdntrxi
Posts: 3540
Joined: Sat Jul 20, 2013 6:11 pm

by spdntrxi

I for one have used my Tacx Neo and stages arm and vectors attached to left power arm.. using a garmin 820/1030 and a pioneer head unit and then DC rainmakers power utility. Only done it once. nothing something I feel like repeating very often... maybe when I get another new PM.

typically I am 51/49 balance.. worse is 53/47 at times.

cdncyclist
Posts: 90
Joined: Wed Feb 17, 2016 12:10 am

by cdncyclist

AeroObsessive wrote:
Sat Feb 15, 2020 12:49 am
cdncyclist wrote:
Fri Feb 14, 2020 10:54 pm
AeroObsessive wrote:
Fri Feb 14, 2020 9:55 pm
^ your experiences here are amazingly normal, in terms of the changing L/R outputs at different cadences/power.

And this is the point I am doggedly banging on about, you don't know if you don't know.

In the application of training - due to the above mentioned variations in L/R balance, accuracy and precision of the power meter in question, a 30 watt variance or more is highly probable. This makes it a worthless training tool.

If an athlete came to me with a Stages and a HR monitor I would not prescribed any power based training, HR would be a more reliable metric in this case. And I think most know my stance on HR.
I concede you may have a point for some people (although still lacking performance data - again the article you provided specifically stated there was no difference in performance). To declare no power is better than single sided (for most people) I find a little outrageoues - and contradictory to many others experience (including mine - I started with single sided and went to double and find no appreciable difference) from not training with power to training with power. But I won't argue, you have provided your rationale, I will wait for better evidence.
Why would there be any effect on performance? The variance of L/R output is perfectly normal. Where the variance of L/R output would cause issues is with the Stages (and other single sided power meters) readings in relation to collection of data and subsequent utilisation of of power readings for training purposes. Maybe y'all have bigger tanks than me, but a variation of 20-30watts (for example) is rather large for a prescribed effort.

As for your anecdote - some people may have perfect 50/50 balance regardless of power output or cadence. But, again, you have no way of knowing that unless verified by another source.

I may be wrong, but I am going to guess you have not performed any direct comparison of your power meters and efforts to accurately state there was no statistically significant variance.

You don't know what you don't know.
I am wary of derailing this thread. What I mean by performance is - does the use of a dual sided power meter lead to power based training that leads to better cycling performance? There are many people that appear to be data obsessed, but I am only interested in data that is usable to improve performance - the rest may be interesting but not of value (responding to your barb that I "don't know what I don't know" with how does knowing help?).

As another example, there are people that may have the same FTP, and the usual approach is to apply zones based on this FTP (although there is the emergence of multiple points to assign zones). However a time trialist vs. a sprinter may have the same FTP, and with the usual approach may have the same zones, but may have different zones if based on physiological testing - so not accurate. But most still extrapolate from FTP testing. The same could arguably apply to drift in PM or power with L/R balance.

In my opinion, the key is precision. If you have a precise powermeter (reproducible readings) you can tailor training to it. Accuracy is important if you are moving between different methods of measurent (as the original post outlined), but at this point I am not convinced that it provides information that is useful to modify power based training that ultimately results in better performance. As mentioned, would love to see evidence of this!

I don't think I have more to add and this might be getting circular so will end here.

Cheers!

golty
Posts: 22
Joined: Sat Feb 15, 2020 5:55 pm

by golty

I'd always trust a tacx neo power reading Vs any other power meter. Mine reads the same as dual side vector 2

by Weenie


davidalone
Posts: 606
Joined: Fri Feb 10, 2012 4:27 pm

by davidalone

I have a Stages, a Quarq, and an Elite Direto ( one of the more accurate Smart trainers in power measurement.)

The Quarq and Elite Direto are within 5 watts of each other.

The Stages reads higher than both. by a really big amount - 20-30 watts higher.

At this point it's pretty much useless as a training tool. I just use it as a rough gauge.

Post Reply