CanadianBiker32

What are your thoughts on this power meter for a date bike. To use off road and also in winter snow in cold temperature s. Like -20c. Etc


Power pod

Link is herr
https://m.probikekit.ca/cycling-power-meters/powerpod-powermeter-v2/11514777.html?affil=thggpsad&switchcurrency=CAD&shippingcountry=CA&thg_ppc_campaign=7170000001309292 6&gclid=CjwKCAjwos7NBRAWEiwAypNCe82e6Ft5rneU1bYwHaRLltnZQ9rkQ92hRQP1-VswLwKELy_VQ1iNtRoCUS8QAvD_BwE&gclsrc=aw.ds&dclid=CJv5zKyQmdYCFVe5TwodqGoO7Q


Thoughts? I know not as accurate as a crank or pedal.type..but to have it protected from off road stuff

Would.u think one could.get an idea of power out put with this device?

noglider 

Very interesting. I want to know how accurate it is. If it's nearly as accurate as the other power meters, this could represent a big change in things.

Seattle Forrest

That's not a power meter.

It's a wind sensor, and an algorithm. It's very much like Strava Power, with a little bit more info. It still doesn't know enough to actually get it right. Maybe it's 10 % off, maybe it's 100 %, you'll have no way of knowing.

For the same $400, you can get a direct force power meter from Stages or 4iiii. They'll be left-only, which means if you have an imbalance they'll be off by 2x that amount. But they actually measure power, and you can probably find a dual sided meter to use for a few minutes (like at the shop) to get an idea whether you have an imbalance and how to adjust the numbers if so. That won't be as accurate as a crank based meter, but it will be night and day better than a power pod.

CanadianBiker32

Thanks

Seattle Forrest

gauvins

I think that you mean that it is not a strain gauge based power meter.

See this review here by DC Rainmaker

Seattle Forrest

@gauvins

A meter is a device that measures something.

A power meter is a device that measures power.

This is NOT a device that measures power.

This is a device that measures wind.

Therefore, this is not a power meter.

gauvins

The powerpod estimates power in watts using a wind gauge. Other meters estimate power using strain gauges.

Some bathroom scales rely on springs. Others on strain gauges. Others on sliding weights as is commonly the case at your doctor's office.

What matters is the concordance (or lack of it) between instruments.

Seattle Forrest

Power meters measure power, they don't estimate it. Let's not play semantics.

A PT has a maximum error of 1.5 %, what's the spec for the wind meter?

gauvins

Please read DC Rainmaker review. Then we can argue if you feel like it

noglider 

If the power inference that this thing makes is accurate, then I'll call it accurate. I think you're saying you expect it to be inaccurate, and you may have good reasons for saying it. But if it proves to be accurate, power meter is a good name for it.

Seattle Forrest

I have, and didn't see an answer to my question. Apparently the thing can be 100 % wrong and it's still operating within spec. Because it's not measuring power.

Seattle Forrest

The only way this thing is "accurate" is if we relax the definition of "accurate" very much.

Bottom line: Why would you pay $400 to get the wrong power numbers when Strava will give them to you for free or you could buy a legitimate power meter for the same $400?

noglider 

I don't know much about these sensors and their usefulness for this application. Why do you expect this system to be inaccurate?

I'm not willing to pay even $400 for a power meter, but I like watching the progress of this stuff.

gauvins

According to this review, the difference between powerPod and a Direct Force Power Meter is less than 2% on average, on rough roads (where powerPod is less accurate because estimating rolling friction becomes delicate).

So, 2% difference would be an upper bound, and it is not entirely clear that the reference DFPM is absolutely correct. If you look at other reviews, you'll see that the charts show several PM tracking closely but with some differences (measurement error).

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I personally would not spend close to a thousand dollars for a power meter. I was lucky to get a used Stages (left crank only) for $200, and am happy with it. Otherwise, I would have seriously considered the PowerPod.

Note that the powerPod is a computer without display. It will record data, meaning that you do not have to ride with a computer (Garmin or other). The downside is that the battery is said to last 20h, so you'll have to recharge every few rides. (Stages runs on 2032 batteries and lasts something like 200hrs. I ride with a Bontrager Node 1.1 with battery life measured in months).

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Final note: DFPMs, contrary to what the name implies, do not directly measure the rider's power. They measure the amount of tiny deflection in sensors. This deflection is used to infer how much pressure is applied on the metered instrument (pedal, crank, wheel, hub and such) and this amount of pressure is used to estimate the amount of watts produced by the rider. This is not trivial. For instance, in another review DC Rainmaker notes that most DFPM (at the time) lose accuracy with elevation changes (because elevation impacts temperature and pressure).

khutch

I know this is an old thread but as an engineer I have to comment. There is no way that I know of that any device can directly measure either power or force. In both cases you measure an effect that a power source or a force produces and you calculate the power or force from that something that you can measure. In this regard the PowerPod is no different from any other power meter. It is unlike the so called DFPM devices in that it does attempt to measure the effects your pedaling force produces on some structural component of your bicycle. The Powerpod measures the accelerations rather than the forces produced by pedaling and it measures wind pressure to produce a good estimate of the aerodynamic force acting on you. From those it solves the Newtonian force diagram to derive your pedaling force and calculate your power. This is a perfectly accurate procedure, the stuff of the homework questions in the back of your physics 101 textbook. Doing it in real time in the real world is trickier of course and Velocomp has developed quite a bit of intellectual property over the years to allow them to do this quite well, actually.

Is it as accurate as a DFPM (and I won't try to change that name even though it is inaccurate)? Much of the time it is! You can read DC Rainmaker's review. It is not as accurate under all conditions however. Over the years Velocomp has refined their software and have closed the gap between their product and the competing products. Clever software can do amazing things. Ultimately clever software may not be sufficient to close every gap in performance between PowerPod and the others. But it still appears to me to be a very useful product. I do not own one but I am thinking of getting one. If you need the best possible performance under the broadest range of conditions then you should consider one of the other power meters. But if you just want a power meter that you can afford and you are not doing something critical to your personal income level, like training for the TdF, then the PowerPod is well worth considering.

redlude97

According to DC Rainmaker's review, its off by as much as 100w and isn't consistent for when it is off or what conditions? Is that to be viewed as accurate?

khutch

Actually according to DC Rainmaker:

"Overall, I’ve found that the PowerPod can be solidly accurate in most situations, assuming you are aware of the limitations – or aware of changes to configuration that could impact it. Further, it’s ability to seemingly ‘heal’ itself does act as a bit of a safety net should the aerodynamic profile change significantly enough to otherwise impact power readers. I’d sum it up as: If you do a clean calibration ride – things are impressively accurate across a wide range of riding environments and positions."

After looking at his data I agree with him. The biggest problem he noted was with cobblestones and there has been a software update to address that which seems to work well. And the unit does tend to overestimate power peaks so if you are really serious about training for whatever reason and need the best power meter technology available then the Powerpod is not it. The Powerpod is a classic disruptive technology, it is not as good as the others but it is cheaper and it is useful for many consumers. And it is improving. The worst thing I can say about it is that it should be sold for half its current price. But, I think that the reason that it is not is that they are still improving the software and they need to keep the price as high as it is for as long as they can to fund that. Eventually someone will make a Powerpod clone which will lower the price and perhaps the DFPM technology will decrease in price too, a decrease that is also long overdue. One thing to keep in mind if you are a Powerpod hater is that it does put price pressure on the technology that you love. You should be rooting for it to succeed and should be grateful for those of us who use it because that will force the DFPM companies to compete!

All things considered I think that it is a good fit for my needs and that makes it a good value. If it doesn't work for you (and DC Rainmaker says it does not meet his needs either even though he is fairly positive about it) then you just buy something else at a higher price. The two next cheapest options are pedal and crank arm meters. Both are one sided in their cheapest form, not a serious deficiency in my case. If I buy a pedal based meter then I have to use pedals that I do not like and I have to buy shoes that are compatible with them which adds to the cost. If I buy a crank arm meter then I have to buy a new crankset and possibly one that will screw up my gearing and which will add to the cost. In both cases while the cost differential between the other meters and Powerpod is relatively small the added costs to put them on my bike increase the differential substantially AND I will have to compromise on a bike setup that I like in order to use them. Not so great a deal for me!

Powerpod is great for a casual power meter user wannabe and that is exactly what I am.

redlude97

On average its similar, but look at the differences in sprint power and the lag in intervals. If you all you want a PM for is to use as a fancy speedometer its probably good enough, but Strava's estimated power is probably good enough also. If you want a PM for training I don't think it would cut it, unless all you do is hold a specific position in an interval

khutch

As I have said I have looked over his data and my conclusion is that it is accurate enough for my purposes. I will blame neither he nor you if that turns out to be untrue. I'm not training for anything and I have no specific application in mind for the data. Having the data will lead to the applications and if I have to be careful about how I collect or use the data for some future purpose that is much better to me than to compromise a bike that I like for every mile that I ride it on the odd chance that I will "need" a DFPM and only a DFPM for some future purpose. Surely the data will be useful for training if used appropriately and surely it is better than Strava which has no estimate for aerodynamic forces, does it? People trained quite effectively before we had power meters or heart rate monitors. If a less capable power meter cannot be used exactly the way you use a DFPM that does not mean it cannot be used.

Velocomp has a new "Aeropod" version of the device that can be used to do useful things when paired with a DFPM so the technology is expanding into an area you might find useful after all. A company called SwissSide apparently thinks so since they are supposed to be coming out with a competing product, also called Aeropod. The squabble over who has the rights to own the name could be interesting if nothing else about the product interests you!

khutch

So, based on the fact that I consider the usual objections to the PowerPod's method of measuring power to be well intentioned nonsense for the most part I finally ordered one. Traditional power meters are better for many purposes because they are a lot harder to fool. In fact it seems unlikely that they can be fooled unless either their mounting or internal components fail. Riding conditions seem very unlikely to fool them and you cannot say that about the Powerpod. It can be fooled under some conditions and while Velocomp has done a lot of work and has had a lot of success in reducing the range of conditions where the device can be fooled significantly there are still some conditions that it handles less accurately and if those really bother you, well you know what to do.Because it uses different (but perfectly valid from a scientific standpoint) techniques to measure power it also provides some interesting data. Things like Cda and Crr. My hope was to have that data, especially the latter since it is hard to get anywhere else. There are some excellent websites where you can get Crr measurements of tires, but only on the tires that they are interested in testing which is a tiny fraction of the tires on the market. I was excited therefore to unbox the PP and start to put it through its paces.

Ah,, but none of that means anything if the device is not reliable and my experience so far says that you need to be concerned about that. The new PP charged fine and it connects properly to my laptop although the included instructions left me on my own to get the proper driver for Windows 10/64. Once I did that I connected it to their Isaac software and I was easily able to pre-configure it for my weight and the bikes weight, my riding position, and some other things. I slapped it on the bike, a very simple task, and tried to pair it with my speed/cadence sensor. No go! Nothing in the instructions and nothing I could think of on my own would make it pair with my speed sensor ( a Bontrager DuoTrap S if anyone cares). Interestingly the pairing process was supposed to end with a solid yellow status light indicating success or a solid red light indicating failure. I got neither. After five minutes of a blinking green lights indicating it was attempting to pair the light just turned off, no status displayed. My professional opinion as an electrical engineer and a radio design engineer at that is that the absence of any status light most likely means that the ANT+ radio in the PP failed to "hear" any signal from the speed sensor at all. I know that the speed sensor is operating, my Lezyne computer hears it just fine.

I am currently waiting to hear back from Velocomp about this. Maybe I've done something wrong, which I doubt because the pairing process is so very simple. Maybe the two are just incompatible although they are not listed as incompatible and I would think I would have gotten the red light in that case. Or maybe the ANT+ radio in the PP has failed since it left the factory or the factory simply is not testing the units for functionality before shipping them. If it is the last possibility then I have to strongly reconsider whether I want this device or not. I am perfectly fine with its known limitations but I don't want it if it will not function reliably out on the road and I have a bad feeling about that based on what I have seen so far. I'll report back when I get some resolution on this....

unterhausen

people always start out positive about pitot tube-based power meters and eventually grow tired of the unreliability. IIRC, Polar used to sell one. Strain gauge based devices get enough hate, and the calculations they use are more straightforward.

sierrabob

@khutch: Have you tried initially holding the PowerPod right next to the Bontrager speed sensor? When riding a spin bike at the gym, pairing of cadence/power/hr frequently won't happen until I almost touch devices and sensors. After that, they work fine.

khutch

Unless they have had more than one oddball power meter in the past the old Polar power meter (which I also had/have) was actually a DFPM whether most "haters" recognize that or not. Most DFPM units measure the pedaling force by the changes it produces in an electrical strain gauge. The Polar measured the pedaling force by using what amounted to a guitar pickup to measure the vibrational frequency of the chain. This seems ridiculous to the average bear but anyone who plays bass guitar or another stringed instrument or who tunes pianos can tell you that it is a perfectly sound method of measuring the force/tension on a vibrating "string". The Polar's problem was that in the field the failure rate after two years was close to 100%. It's hard to make a product succeed in the marketplace with that reliability record....

As it turns out I was able to get approved to post on the Velocomp forum in less than 8 hours. I feared it could be a week or more. An email to them last Saturday has still not been answered but I posted the same story to their forum yesterday and got a response this morning asking me to email them. Again. So I have just done that and I will wait a little while to see if they respond quicker once you've gotten their attention in their forum. Don't know what the odds of that are since I have seen people posting there asking when they would get a response a week after getting the same request to email them privately. I'm not going to wait a week. An out of the box failure like this should be embarrassing enough to a company that they would respond immediately. If they won't then I don't think they are a company I want to deal with.

Sure, I'd be willing to take the time to position the PP right next to the speed sensor and try to pair them. As an RF engineer I would not normally do that because putting the receiver right next to the transmitter can be as problematic as putting it too far away. The strong TX signal may overload the RX! But it's worth a shot, thanks for the suggestion and for the report that it has worked for you. It's odd if the PP can receive the speed sensor signal from the handlebars once it has been paired but cannot hear it from that location before it is paired. I guess I have seen odder things however.

I do have the nuclear option: an RMA and a prepaid shipper to return the PP to the retailer for a refund. I'll use it if I have to....

khutch

Velocomp has responded to my latest email already, so no complaints about the response time to the second email. Still no response to the first and I don't suppose I will get one now since they undoubtedly know that both are from the same person. I would typify the response as "it can't be our fault, it must be the other guy's product"!

In this case they say it must be the wheel speed sensor.

Which works perfectly fine with my Lezyne computer.

And which, along with it's battery and the bicycle, is just a few weeks old.

Their suggestion is to remove the battery from the sensor, PUT IT BACK IN BACKWARDS FOR 10 SEC, reinstall it correctly and try to pair again. Kids, kids, kids I am an electrical engineer and I do not trust other electrical engineers to design their products with reverse polarity protection. They should on battery powered equipment where the user can easily install the battery backwards but did they? Do you feel lucky today, punk?? I would never tell anyone to put a battery in backwards unless it clearly says to do that in the owner's manual for the equipment. So, I must reject this suggestion but I will take the sensor off the bike so that I can get to the battery compartment, remove the battery for a few minutes, replace it with a fresh battery, and try it again. Reversing the battery on a product that has reverse polarity protection will do nothing because the reverse polarity protection is there specifically to prevent that from doing anything. Reversing the battery on a non protected product may, of course, damage or destroy it. I don't get the advice to reverse the battery at all. But removing the battery for a few minutes will guarantee that the sensor does a full power on reset when it comes back up and a fresh battery will guarantee that my present battery has not drained during the four/five weeks it has been in use. As if....

They also suggested that I try to pair it with the GSC-10 sensor on my other bike. Their literature clearly states that the PP will not work with the GSC-10 but they say I should try it anyway because, you know, it might work! Curious .... but easy enough to try.

So I have three things I can try tonight. If any of them work, great. If not I can report back to Velocomp and see if there is anything else they can or will do. If not then back to the dealer the PP goes! My plan is to try the suggestions in the order of easiness:

1) sierrabob's suggestion to move the PP close to the sensor
2) try to pair to the GSC-10 sensor
3) replace the battery

Thanks for listening and making suggestions.