Seattle Forrest

Would you agree that a bathroom scale measures your weight? Because it's using the same proxy a direct force power meter uses.

LAJ

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.

surak

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.

merlinextraligh

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.

rubiksoval

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.

Metallifan33

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"

spelger

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

sfrider 

You're right. Late night math fail.

fstshrk

I am selling a Vector 2 dual-sided on Ebay for 375 right now. Just saying.

Seattle Forrest

​​​​​​​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.

Seattle Forrest

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!

RChung

https://en.wikipedia.org/wiki/Barome...'s_account

rubiksoval

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

Seattle Forrest

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.

sfrider 

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.
​​​​​​​

RChung

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).

sfrider 

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.

LAJ

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.

spelger

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.

ridethecliche

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.

RChung

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?

... please.

Boom, tish. Thanks folks, I'll be here all week.

guadzilla

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)

colnago62

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.

colnago62

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.

RChung

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.