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Power meter comparison (powerpod?) - what is best/easiest without spending a fortune?

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Power meter comparison (powerpod?) - what is best/easiest without spending a fortune?

Old 06-26-20, 10:08 AM
  #51  
Seattle Forrest
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Originally Posted by spelger View Post
let me begin with the fact that I do not own power meter. That said, unless the meter is physically attached to your legs then the meter is not measuring leg power either. Both measure a cyclists power output via a proxy. Just a different one.
Would you agree that a bathroom scale measures your weight? Because it's using the same proxy a direct force power meter uses.
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Old 06-26-20, 10:25 AM
  #52  
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Let me begin by saying I don't own a gas oven, but your pedals aren't attached to your quads, but the bike still moves.
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Originally Posted by Bah Humbug View Post
In other news, to effect quick passes of other cyclists out this morning, I did dial it up to 400w to pass several times. It doesn't actually feel like much of anything for that duration. Not sure what that guy was on about.
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Old 06-26-20, 10:35 AM
  #53  
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I have multiple bikes so a single dual-sided pedal PM is cheaper that multiple PMs for every bike I want.

The conundrum of dual-sided vs single is that one won't know for sure whether a single-sided PM is sufficient without seeing what the dual-sided reports first.

I suspected I had a leg strength imbalance, which my pedals first confirmed and then a later bike fitting also showed, but interestingly after that bike fitting the imbalance switched over. So now I know that saddle height, along with fatigue, cadence, and torque, all have an effect on L/R balance. In turn, I can tell if my fit's gone too extreme after making changes to my saddle position, cleats, or other equipment by seeing if that balance changes noticeably. The PM isn't the only thing I use to gauge fit, since I can now estimate the numbers by feel from experience, but it's better than relying solely on subjective judgment.
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Old 06-26-20, 10:45 AM
  #54  
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Originally Posted by asgelle View Post
Your suspicion is wrong. Most cases I've seen show a variable imbalance which changes with power. In a fair number of cases even the dominant leg will change (though this mean that at some point there is a 50/50 distribution).
My sample of one, my power is virtually 50/50 when I’m working hard. Just cruising along I can see as much as a 6% difference (47-53).

my assumption is that when I working hard, I fully recruit both legs, but below a close to maximal effort I favor a dominant leg.
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Old 06-26-20, 11:05 AM
  #55  
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Originally Posted by merlinextraligh View Post
My sample of one, my power is virtually 50/50 when I’m working hard. Just cruising along I can see as much as a 6% difference (47-53).

my assumption is that when I working hard, I fully recruit both legs, but below a close to maximal effort I favor a dominant leg.
I've noticed similar. Harder efforts gets things split evenly, versus cruising is just whatever. My cadence changes quite a bit as well, though, with very hard efforts generally at 100 rpm+, threshold at 95+, and z2 in the 80s. When I want to go hard, it seems I default to whatever gets me the most watts, and apparently that's both legs spinning.
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Old 06-26-20, 11:26 AM
  #56  
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Originally Posted by Seattle Forrest View Post
I use Vectors. My L/R balance changes dynamically with effort, fatigue, and moon phase.
Originally Posted by phrantic09 View Post
I have the Vector 3, got them factory refurbished through western bike and only paid something like $500 for a dual sided set. Same warranty as new and they have worked great so far.
Originally Posted by guadzilla View Post
I used machine oil and that helped reduce the issues, but she still reported an occasional "low battery warning" that would then go away. In the end, it just wasnt worth the drama. But a couple of other friends - including one who rides 20k km a year - have not had issues either, so i suspect its a bit hit-or-miss. Glad to know yours are working well.

I got a single sided Stages PM - back when they first came out - to put on my rain bike, thinking i didnt really need an expensive power meter on a beater bike. The numbers were around 20% off. I sold it and got another Quarq.
I got the Vector 3s last month. Wanted the Assiomas, but they were sold out and a 60 day delay on their website (they are available now).
The V3's issues stemmed from the design of the battery door. They re-designed the door 2 times and I thought all the bugs may have been worked out. Apparently, in May of this year, they did another redesign, however they are back ordered on the new door.
I had power spikes and dropouts on mine. I removed the batteries that they came with and replaced them with the 1 battery type and that has helped some. It constantly reads higher than my Tacx Neo 2T (however that could mean that the Tacx is wrong or both are wrong)... I would however tend to believe the Tacx over the V3 based on my experiences with the V3. For example, the Tacx registered 597 kj of work on yesterday's ride vs. 672 kj on the V3.
Hopefully Garmin is able to restock the new doors soon and I'll be able to get them replaced. They call it the "Vector 3 Small Parts Kit"
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Old 06-26-20, 01:06 PM
  #57  
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Originally Posted by rubiksoval View Post
Come again?

Power output. Both are not measuring power output. One is measuring the amount of torque applied via strain gauges, the other is measuring opposing forces.

Two entirely different things.
Originally Posted by Seattle Forrest View Post
Would you agree that a bathroom scale measures your weight? Because it's using the same proxy a direct force power meter uses.
Originally Posted by LAJ View Post
Let me begin by saying I don't own a gas oven, but your pedals aren't attached to your quads, but the bike still moves.
not really getting the hate. the typical power meter measures force at the cranks (as an aside, not sure how a hub meter works) and converts that to power. this other meter measures the force of air and uses speed/cadence/weight/math to convert to power. just different. it ft really works i think it is pretty cool to be able to accomplish the same thing cheaper. bringing the price point down would open up to more users. just wonder if it is really reliable.

here is something i just found, (most) everybody likes garmin...

https://www.bicycling.com/bikes-gear...ctor-air-news/

-scott
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Old 06-26-20, 01:35 PM
  #58  
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Originally Posted by WhyFi View Post
I think that you should be doubling that error. If you're at 400w total, 55:45, your left leg would be putting out 220w (vs 180w of the right leg) and the Stages would then double that to 440w, which is a 10% difference vs the real total.
You're right. Late night math fail.
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Old 06-26-20, 01:41 PM
  #59  
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I am selling a Vector 2 dual-sided on Ebay for 375 right now. Just saying.
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Old 06-26-20, 01:44 PM
  #60  
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Originally Posted by spelger View Post
not really getting the hate. the typical power meter measures force at the cranks (as an aside, not sure how a hub meter works) and converts that to power. this other meter measures the force of air and uses speed/cadence/weight/math to convert to power. just different. it ft really works i think it is pretty cool to be able to accomplish the same thing cheaper. bringing the price point down would open up to more users. just wonder if it is really reliable. here is something i just found, (most) everybody likes garmin... https://www.bicycling.com/bikes-gear/a29788744/garmin-vector-air-news/ -scott
​​​​​​​Nobody hates you, or your opinion. People disagree, that's very different than hate.

Bathroom scales can't actually measure weight. They measure deflection, caused by weight. Most people would say that's a distinction without a difference, I bet you're one of them. Power meters measure deflection caused by force, and they measure how quickly and often that force is being applied. Know those things, and you know power with absolute certainty. That's why a lot of PMs can deliver accuracy and precision with with a maximum 1% error.

Air pod meters are not doing the same thing. They're measuring one of many things needed to derive ("back into") power, asking a couple other, and using standard assumptions about the rest. It's more like trying to guess what a person weighs from their clothes size, except even less accurate. What's the maximum error spec for a PowerPod?

A bike example. You can use a power meter to do aerodynamic testing. A PowerPod doesn't know if you're sitting upright in parachute pants or wearing a skin suit riding on the aerobars.
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Old 06-26-20, 01:46 PM
  #61  
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Originally Posted by Metallifan33 View Post
I got the Vector 3s last month. Wanted the Assiomas, but they were sold out and a 60 day delay on their website (they are available now).
The V3's issues stemmed from the design of the battery door. They re-designed the door 2 times and I thought all the bugs may have been worked out. Apparently, in May of this year, they did another redesign, however they are back ordered on the new door.
I had power spikes and dropouts on mine. I removed the batteries that they came with and replaced them with the 1 battery type and that has helped some. It constantly reads higher than my Tacx Neo 2T (however that could mean that the Tacx is wrong or both are wrong)... I would however tend to believe the Tacx over the V3 based on my experiences with the V3. For example, the Tacx registered 597 kj of work on yesterday's ride vs. 672 kj on the V3.
Hopefully Garmin is able to restock the new doors soon and I'll be able to get them replaced. They call it the "Vector 3 Small Parts Kit"
Sorry to hear it.

A pedal power meter should read a couple % higher than a hub meter because of drive train losses, but what you saw is crazy!
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Old 06-26-20, 01:57 PM
  #62  
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Originally Posted by Seattle Forrest View Post
Bathroom scales can't actually measure weight. They measure deflection, caused by weight. Most people would say that's a distinction without a difference, I bet you're one of them. Power meters measure deflection caused by force, and they measure how quickly and often that force is being applied. Know those things, and you know power with absolute certainty. That's why a lot of PMs can deliver accuracy and precision with with a maximum 1% error.

Air pod meters are not doing the same thing. They're measuring one of many things needed to derive ("back into") power, asking a couple other, and using standard assumptions about the rest. It's more like trying to guess what a person weighs from their clothes size, except even less accurate. What's the maximum error spec for a PowerPod?

A bike example. You can use a power meter to do aerodynamic testing. A PowerPod doesn't know if you're sitting upright in parachute pants or wearing a skin suit riding on the aerobars.
https://en.wikipedia.org/wiki/Barome...'s_account
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Old 06-26-20, 02:01 PM
  #63  
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Originally Posted by Seattle Forrest View Post

A bike example. You can use a power meter to do aerodynamic testing. A PowerPod doesn't know if you're sitting upright in parachute pants or wearing a skin suit riding on the aerobars.

Even better, if you read through the aeropod information , Velocomp even states this outright.

What's In The Box

  • AeroPod sensor and pitot tube
  • Handlebar mount
  • USB cable
  • Link to Isaac software for Mac/PC
  • Link to Comprehensive Instructions
  • 1 year warranty

Items Not included

  • ANT+ bike computer, required
  • ANT+ speed sensor, required
  • Direct Force Power Meter, required for CdA measurement
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Old 06-26-20, 02:21 PM
  #64  
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How do you estimate the height of a building using a barometer?

Drop it from the roof and measure the time it takes to fall to the ground.

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Old 06-26-20, 02:34 PM
  #65  
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Originally Posted by Seattle Forrest View Post
Power meters measure deflection caused by force, and they measure how quickly and often that force is being applied. Know those things, and you know power with absolute certainty. That's why a lot of PMs can deliver accuracy and precision with with a maximum 1% error.
You also need an angular sensor to measure power at the pedal. Integrate force over distance (i.e., the pedal spherical movement distance) and you get work; divide the work by the time it took, or the measurement interval, and you get average power for the time interval.
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Old 06-26-20, 02:35 PM
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Originally Posted by rubiksoval View Post
Even better, if you read through the aeropod information , Velocomp even states this outright.
We tried doing some comparison aero testing of the Power Pod, the Notio Konect, and the Alphamantis Aerostick in the wind tunnel and the road (with a Power Tap wheel). The Power Pod was hobbled by its software (this was in 2018 -- maybe the s/w is better now).
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Old 06-26-20, 02:48 PM
  #67  
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Originally Posted by Metallifan33 View Post
I got the Vector 3s last month. Wanted the Assiomas, but they were sold out and a 60 day delay on their website (they are available now).
The V3's issues stemmed from the design of the battery door. They re-designed the door 2 times and I thought all the bugs may have been worked out. Apparently, in May of this year, they did another redesign, however they are back ordered on the new door.
I had power spikes and dropouts on mine. I removed the batteries that they came with and replaced them with the 1 battery type and that has helped some. It constantly reads higher than my Tacx Neo 2T (however that could mean that the Tacx is wrong or both are wrong)... I would however tend to believe the Tacx over the V3 based on my experiences with the V3. For example, the Tacx registered 597 kj of work on yesterday's ride vs. 672 kj on the V3.
That's not a small error!

I do know with the Assiomas is it's super important to only pair with the left pedal, whereas pairing with the right pedal leads to extremely erratic readings.
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Old 06-26-20, 03:02 PM
  #68  
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Originally Posted by spelger View Post
not really getting the hate. the typical power meter measures force at the cranks (as an aside, not sure how a hub meter works) and converts that to power. this other meter measures the force of air and uses speed/cadence/weight/math to convert to power. just different. it ft really works i think it is pretty cool to be able to accomplish the same thing cheaper. bringing the price point down would open up to more users. just wonder if it is really reliable.

here is something i just found, (most) everybody likes garmin...

https://www.bicycling.com/bikes-gear...ctor-air-news/

-scott
It's not hate by any stretch of the imagination. It just makes no sense when an opinion is offered as fact, without a shred of real life experience. I know what works for me, and with a choice of a few power measuring devices, I can actually back that up with real life data. I can test the output of my hub based with crank based, or pedal based, and compare. I can also verify all the rest, with all the rest, based on that assortment. I will say, when certain forum members weigh in, I sit back and learn. That really works very well.
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Originally Posted by Bah Humbug View Post
In other news, to effect quick passes of other cyclists out this morning, I did dial it up to 400w to pass several times. It doesn't actually feel like much of anything for that duration. Not sure what that guy was on about.
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Old 06-26-20, 03:11 PM
  #69  
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Originally Posted by Seattle Forrest View Post
​​​​​​​Nobody hates you, or your opinion. People disagree, that's very different than hate.

Bathroom scales can't actually measure weight. They measure deflection, caused by weight. Most people would say that's a distinction without a difference, I bet you're one of them. Power meters measure deflection caused by force, and they measure how quickly and often that force is being applied. Know those things, and you know power with absolute certainty. That's why a lot of PMs can deliver accuracy and precision with with a maximum 1% error.

Air pod meters are not doing the same thing. They're measuring one of many things needed to derive ("back into") power, asking a couple other, and using standard assumptions about the rest. It's more like trying to guess what a person weighs from their clothes size, except even less accurate. What's the maximum error spec for a PowerPod?

A bike example. You can use a power meter to do aerodynamic testing. A PowerPod doesn't know if you're sitting upright in parachute pants or wearing a skin suit riding on the aerobars.
i know they are not doing the same thing. i said as much in my last post. if this meter can be accurate (they claim 2%) i would like to see them succeed. new stuff is always hard in the beginning. take autonomous vehicles, they scare the crap out of me today but sometime in the future they will be great, especially for someone who really can't drive to save their life (or ours).

the Cda thing is a little weird. Fitness Equipment supports this too but who tells the trainer in the drops now, on the hoods now, back in the drops...don't know why they bothered with that.
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Old 06-26-20, 04:12 PM
  #70  
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In this day and age, there's absolutely no reason to get garbage like a powerpod instead of getting a used crankarm based power-meter. You can get a used one for 200-250 with some searching.

Don't waste your time or money. Unless you don't care about accuracy or precision in which case you may as well get a random number generator app for your phone and run that instead.
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Old 06-26-20, 06:54 PM
  #71  
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Originally Posted by spelger View Post
i know they are not doing the same thing. i said as much in my last post. if this meter can be accurate (they claim 2%) i would like to see them succeed. new stuff is always hard in the beginning
I don't have a philosophical problem with the Power Pod or the way it measures drag force, and I certainly don't have a problem with measuring the "demand side" of power rather than the supply side and using that to make estimates and inferences. If it worked well, or even if it worked acceptably and fulfilled a value proposition, I would be happy. However, it's not new -- it's been around for a pretty long time, long enough to evaluate its accuracy, precision, and usefulness in comparison to other competing products at their price points. We buy power meters because we hope that the information they provide will answer hard questions that we couldn't otherwise answer. The empirical problem with the Power Pod is that when you have a hard and subtle question, it raises a new question: can you trust the data that it provides?

take autonomous vehicles
... please.

Boom, tish. Thanks folks, I'll be here all week.
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Old 06-26-20, 09:22 PM
  #72  
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Originally Posted by spelger View Post
not really getting the hate. the typical power meter measures force at the cranks (as an aside, not sure how a hub meter works) and converts that to power. this other meter measures the force of air and uses speed/cadence/weight/math to convert to power. just different. it ft really works i think it is pretty cool to be able to accomplish the same thing cheaper. bringing the price point down would open up to more users. just wonder if it is really reliable.
I think the issue is that one is a direct measurement of force - it is consistent and repeatable.

The other is a *calculation* of force, which cannot factor in things like rolling resistance and only estimates things like wind resistance. This may be directionally accurate but it is not even close to being precise enough to do structured power-based training: you might as well just stick to HR, in that case.

What I am waiting for is one of these wind speed sensors that can be paired with a power meter to do A/B drag. Would be a great way to tune my TT position and set up on the fly. I know that some of them are starting to offer this, but from what i gather, it is still not quite ready for primetime and requires far more analysis than my lazy ass could be bothered (if i was winning races, it is one thing - but as mid-pack bantha fodder, there are limits to how far i go for my geekery)

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Old 06-26-20, 10:08 PM
  #73  
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Originally Posted by Seattle Forrest View Post
Nobody hates you, or your opinion. People disagree, that's very different than hate.

Bathroom scales can't actually measure weight. They measure deflection, caused by weight. Most people would say that's a distinction without a difference, I bet you're one of them. Power meters measure deflection caused by force, and they measure how quickly and often that force is being applied. Know those things, and you know power with absolute certainty. That's why a lot of PMs can deliver accuracy and precision with with a maximum 1% error.

Air pod meters are not doing the same thing. They're measuring one of many things needed to derive ("back into") power, asking a couple other, and using standard assumptions about the rest. It's more like trying to guess what a person weighs from their clothes size, except even less accurate. What's the maximum error spec for a PowerPod?

A bike example. You can use a power meter to do aerodynamic testing. A PowerPod doesn't know if you're sitting upright in parachute pants or wearing a skin suit riding on the aerobars.
That YouTube guy that does all those in-depth reviews on bike equipment actually said the power pods were as accurate as other power meters out there under steady pace riding.
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Old 06-26-20, 10:09 PM
  #74  
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Originally Posted by Seattle Forrest View Post
Nobody hates you, or your opinion. People disagree, that's very different than hate.

Bathroom scales can't actually measure weight. They measure deflection, caused by weight. Most people would say that's a distinction without a difference, I bet you're one of them. Power meters measure deflection caused by force, and they measure how quickly and often that force is being applied. Know those things, and you know power with absolute certainty. That's why a lot of PMs can deliver accuracy and precision with with a maximum 1% error.

Air pod meters are not doing the same thing. They're measuring one of many things needed to derive ("back into") power, asking a couple other, and using standard assumptions about the rest. It's more like trying to guess what a person weighs from their clothes size, except even less accurate. What's the maximum error spec for a PowerPod?

A bike example. You can use a power meter to do aerodynamic testing. A PowerPod doesn't know if you're sitting upright in parachute pants or wearing a skin suit riding on the aerobars.
That YouTube guy that does all those in-depth reviews on bike equipment actually said the power pods were as accurate as other power meters out there under steady pace riding.
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Old 06-26-20, 10:36 PM
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RChung
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Originally Posted by colnago62 View Post
That YouTube guy that does all those in-depth reviews on bike equipment actually said the power pods were as accurate as other power meters out there under steady pace riding.
I'm not quite sure which "YouTube guy" you're talking about but "steady pace riding" is the lowest bar. For steady state riding all you really need is a speedometer.
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