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Re: "Best" power meter - money no object [rruff] [ In reply to ]
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rruff wrote:
Field testing for CdA, where you are using the PM as a scientific instrument.

The only "accuracy testing" I've seen is when he compares the numbers from different PMs.

As long as there are consistency to the readings why would accuracy testing be all that important?
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Re: "Best" power meter - money no object [mickison] [ In reply to ]
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There are a variety of reasons you might want accuracy as well as consistency. For example when you someday switch power meters, or when you have power meters on multiple bikes. Or if you race on Zwift and don't want to be that jerk who is zdoping. You specifically might not have a good reason to care (at the moment), but others do.
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Re: "Best" power meter - money no object [el gato] [ In reply to ]
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Unlimited budget? 2 SRMs, so that when one goes in for service I have a backup. What I recall reading somewhere, but could be mistaken, is that while other PM's are as good for steady state and most riding situations, SRM still handles peak sprinting forces and power better. Although sprint power and force isn't applicable for 99.9% of my riding, it would be nice to know that its there if I do decide to unleash my massive 20,000W sprint..

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Re: "Best" power meter - money no object [JasoninHalifax] [ In reply to ]
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Lord knows you wouldn't want your PM to only indicate 19,990. /pink
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Re: "Best" power meter - money no object [Tom_hampton] [ In reply to ]
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Tom_hampton wrote:
Lord knows you wouldn't want your PM to only indicate 19,990. /pink

I would be really pissed if it showed a peak of 19,999.

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Re: "Best" power meter - money no object [mickison] [ In reply to ]
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mickison wrote:
rruff wrote:
Field testing for CdA, where you are using the PM as a scientific instrument.

The only "accuracy testing" I've seen is when he compares the numbers from different PMs.

As long as there are consistency to the readings why would accuracy testing be all that important?

1. If you ever switch pm's or use a smart trainer with a pm and your power numbers are now different, which pm do you believe? How do you now set your FTP or zones?
2. Aero testing - an inaccurate pm will lead to an inaccurate CdA
3. Analyzing data - whether you use the BBS tool or just want to compare w/kg to others on the same course. An inaccurate pm could lead you down the wrong path.

get comfortable being uncomfortable
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Re: "Best" power meter - money no object [stevej] [ In reply to ]
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I am with Steve on this one; money no object its a SRM hands down. I ride a quarq since money does matter.

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Re: "Best" power meter - money no object [jbank] [ In reply to ]
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jbank wrote:
There are a variety of reasons you might want accuracy as well as consistency. For example when you someday switch power meters, or when you have power meters on multiple bikes. Or if you race on Zwift and don't want to be that jerk who is zdoping. You specifically might not have a good reason to care (at the moment), but others do.

If I switch power meters, I retest my ftp. I used to attend a computrainer class. computrainer power numbers were always higher than my power meter. But the difference was consistence. Is there somebody out there that has done accuracy tests with most power meters and has charted the differences? so if ftp on power meter X is 256 then your ftp on power meter Y is 262. I don't think I've seen one but maybe it exists. If not, then you're back to if you switch power meters you need to retest. I can't say I've test a lot of power meters, but are there often such huge differences that you would cause a zdoping issue. I wouldn't think most differences would be greater than say 5-10 watts between power meters but I don't really have much experience with that.
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Re: "Best" power meter - money no object [mickison] [ In reply to ]
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You would think most wouldn't be different by more than 5-10 watts, but if you are including the power meters in various trainers, I think you would sadly be wrong. My stupid kickr was pretty wildly off as just one example. Fortunately had some quarqs that I trusted that helped identify just how inaccurate it was. Total pain to deal with its inaccuracy. It was consistent though.
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Re: "Best" power meter - money no object [mickison] [ In reply to ]
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To go back to the whole "just retest your FTP". Does your FTP never change? Do you test your FTP so frequently that you feel that you know it (for a given PM) precisely on any given day? If not, when you retest with your new PM, you will get a new FTP number, but you will lose the continuity in your training numbers. Was your recent training since your last FTP test effective? Maybe not a huge deal, but still pretty annoying if you are trying to monitor your fitness over a long period of time and trying to assess whether your training has been effective. Sure, this is probably not that big a deal if your PM is within 1-2%, but at 5% or 10% I would find that really annoying.

You can probably come up with some ways to handle that situation and work around the annoyance. I'm not saying that a consistent but inaccurate power meter is useless. But does accuracy add value? Yes, it does.
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Re: "Best" power meter - money no object [klehner] [ In reply to ]
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klehner wrote:
Benv wrote:

I have 3 powermeters - an old Powertap Pro+ hub, a Power2Max in a Rotor 3D crank, and a 3rd generation Stages (Left side only). They have all been very reliable, they give the same numbers


Do you have a frictionless drivetrain?
I do not have a frictionless drivetrain nor do my legs have the ability to apply power at a range of precision that is smaller than the differences between my power meters.
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Re: "Best" power meter - money no object [el gato] [ In reply to ]
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If only someone had done research on this very topic: OMG they did!!!!

Accuracy of Cycling Power Meters against a Mathematical Model of Treadmill Cycling
Authors Thomas Maier, Lucas Schmid, Beat Müller, Thomas Steiner, Jon Peter Wehrlin

http://dx.doi.org/10.1055/s-0043-102945 Published online: 8.5.2017 Int J Sports Med 2017; 38: 456–461

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Re: "Best" power meter - money no object [desert dude] [ In reply to ]
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how very Andrew Coggan of you... ;)

desert dude wrote:
If only someone had done research on this very topic: OMG they did!!!!

Accuracy of Cycling Power Meters against a Mathematical Model of Treadmill Cycling
Authors Thomas Maier, Lucas Schmid, Beat Müller, Thomas Steiner, Jon Peter Wehrlin

http://dx.doi.org/10.1055/s-0043-102945 Published online: 8.5.2017 Int J Sports Med 2017; 38: 456–461

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Re: "Best" power meter - money no object [el gato] [ In reply to ]
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SRM easily. The latest has a replaceable battery to avoid sending it in, which I actually believe is not a good thing. Sending in SRMs every 3-5 years for a battery replacement allows SRM to do a full PMCS on it and I believe that extends the life, as I have 3 SRMs, aging from 10 years old, 7 years old and 1 year old.

PT/Quarq, etc are very good, for sure...



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Re: "Best" power meter - money no object [desert dude] [ In reply to ]
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desert dude wrote:
If only someone had done research on this very topic: OMG they did!!!!

Accuracy of Cycling Power Meters against a Mathematical Model of Treadmill Cycling
Authors Thomas Maier, Lucas Schmid, Beat Müller, Thomas Steiner, Jon Peter Wehrlin

http://dx.doi.org/10.1055/s-0043-102945 Published online: 8.5.2017 Int J Sports Med 2017; 38: 456–461


The "Limitations" section is pretty important, though. Temperature, vibration, etc.
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Re: "Best" power meter - money no object [desert dude] [ In reply to ]
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desert dude wrote:
If only someone had done research on this very topic: OMG they did!!!!


Accuracy of Cycling Power Meters against a Mathematical Model of Treadmill Cycling
Authors Thomas Maier, Lucas Schmid, Beat Müller, Thomas Steiner, Jon Peter Wehrlin

http://dx.doi.org/10.1055/s-0043-102945 Published online: 8.5.2017 Int J Sports Med 2017; 38: 456–461


Yup, I've read that before. Hence this this comment in my original post:

"It seems to me that the top offerings from many manufacturers rival the accuracy of the SRM"


Though it's hard to draw any real conclusions about some of the PM's in the report, like the Vector's, when they only tested one sample.


So, if we make the assumption that most of the 'premium' offerings (i,e, not those targeted for budget-conscious buyers like single-sided pedals) have similar accuracy, what differentiates the 'best' PM nowadays?
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Re: "Best" power meter - money no object [CPT Chaos] [ In reply to ]
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CPT Chaos wrote:
SRM easily. The latest has a replaceable battery to avoid sending it in, which I actually believe is not a good thing. Sending in SRMs every 3-5 years for a battery replacement allows SRM to do a full PMCS on it and I believe that extends the life, as I have 3 SRMs, aging from 10 years old, 7 years old and 1 year old.

PT/Quarq, etc are very good, for sure...
I prefer to charge/change the battery myself rather than sending it in. I'm in the process of changing the batteries in my SRM and noticed the service center in CO used EVE batteries on the last change rather than the original Eagle Picher. EVE stands for "Energy Very Endure" so I'm assuming they are a lower cost option from China. I don't know what PMCS is but I think it's positive you no longer have to send the new ones in for service.
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Re: "Best" power meter - money no object [Tom_hampton] [ In reply to ]
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Tom_hampton wrote:
Not if you believe dcr :

https://www.dcrainmaker.com/...de-2017-edition.html

If you search you’ll find Coggan and dc rainmaker have gotten into arguments multiple times on here about the accuracy/precision/whatever about the testing the latter does. The gist of it is that there is a difference between power meters with SRM being the best but for 99% of riders it doesn’t matter.

Matt
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Re: "Best" power meter - money no object [el gato] [ In reply to ]
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el gato wrote:
Back when there were only a handful of players in the market, SRM used to be the 'gold standard'. Nowadays, I'm not so sure that's the case any more. It seems to me that the top offerings from many manufacturers rival the accuracy of the SRM, and most don't involve the hassle of having to send in your PM for service periodically. So, if you were to buy a power meter today and had an unlimited budget, what would you buy, and why? For argument's sake, let's assume that it will live on one bike permanently, so things like being able to easily swap from one bike to another aren't a factor.

Garmin and Pioneer will give you the most insight in to your pedal stroke, if you know what to do with that data those two are great. Stages dual leg are bullet proof.
I have PT wheel, Powertap P1 pedals, Garmin pedals, stages dual leg and stages single on my cross.
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Re: "Best" power meter - money no object [el gato] [ In reply to ]
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el gato wrote:
If we make the assumption that most of the 'premium' offerings (i,e, not those targeted for budget-conscious buyers like single-sided pedals) have similar accuracy, what differentiates the 'best' PM nowadays?
If you take accuracy off the table as a differentiator, which I agree is appropriate with the current offerings, then the differences become specific to each individual's preferences...

You already struck portability as a criterion, so that does not leave much as a differentiator.

Is it OK to assume "best" would be total power? If so, then that reduces choices to hub, crank, chainring, and dual-side pedal and crank arm offerings.

Is it OK to assume that "best" means accurate left/right power? Then, that reduces offerings to crank arms and pedals.

Is it OK to assume that "best" means pedal dynamics? Then, that reduces the offerings to pedals.

You eliminated budget-conscious, so does that filter Favero pedals?

By your filters and criteria, it seems like the best power meter is either PowerTap P1 or Garmin Vector 3.

OTOH, if your best diminishes pedal dynamics in favor of freedom to use any pedals, then Best would be Stages V3 dual sided or Shimano's new PM (when it is ready for prime time).

\Thread
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Re: "Best" power meter - money no object [el gato] [ In reply to ]
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Nobody has mentioned Power2Max yet. I have two - one for nearly three years, and the second for a bit over one year. Other than change the batteries once a year, I haven't had to do a single thing with them. They simply work. I had two Powertap wheels for eight years (race and training), and had a few issues over that time span with them. No experience with any other PM's, but highly recommend the P2M!


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Re: "Best" power meter - money no object [el gato] [ In reply to ]
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Does SRM have active temperature compensation yet?
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Re: "Best" power meter - money no object [mickison] [ In reply to ]
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mickison wrote:
As long as there are consistency to the readings why would accuracy testing be all that important?

If a PM is consistent (precise) then accuracy is a trivial matter of calibration. In other words precision is the main problem.
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Re: "Best" power meter - money no object [el gato] [ In reply to ]
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If money is no object, the answer isn't one powermeter, but several. First, get a hub-based powertap for each rear wheel you will be using. Then, just so you can keep an eye on drivetrain friction, get an SRM or Power2max.

IMO, there is no substitute for a Powertap hub when it comes to field testing - particularly Chung testing. Crank and pedal based power are too loosely correlated with what actually gets to the wheel to be useful for many things.

If I had relied on my SRM alone, I would have blithely gone through life believing that Q-Rings and Osymmetric Rings were actually gaining me an extra 20 watts. The powertap set me straight on that. Looking back, the rolling resistance tests I did with the SRM are far more variable than the Powertap tests, which were dead-on repeatable.
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Re: "Best" power meter - money no object [desert dude] [ In reply to ]
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desert dude wrote:
If only someone had done research on this very topic: OMG they did!!!!

Accuracy of Cycling Power Meters against a Mathematical Model of Treadmill Cycling
Authors Thomas Maier, Lucas Schmid, Beat Müller, Thomas Steiner, Jon Peter Wehrlin


http://dx.doi.org/10.1055/s-0043-102945 Published online: 8.5.2017 Int J Sports Med 2017; 38: 456–461

From that article:


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