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Don't know if it's already been mentioned on here? Looks like voodoo to me 🙂
Cheap if it works though.
😯
Looks like a load of rubbish to me!
LBS owner has the full head unit version, he's used PM's for about 10-12 years and he's amazed at how close it's tracking his Powertap (comparing it side by side on Training Peaks (I think)).
It's not really a power meter though is it? It's a (possibly quite accurate) power estimator.
I guess it might work road bikes with (virtually) no friction between the road and the bike. I can't see it being any use for MTB though.
It'd have to know a) your exact weight and b) your friction coefficient, no?
a) is relatively easy to get to within a kg or so but b) is hard to estimate, no?
i guess, with a lot of power stuff, it doesn't have to be accurate with its numbers, it just has to consistent with its numbers
How does it know when your freewheeling though? Sounds like a novel concept, I'm just not sure how well it'll work in the real world.
How does it know what riding position you are currently in?...and therefor the drag coefficient. What about the road surface? Do you have to weigh your water bottle before you set off and update the device when you go to the toilet?
Sounds very inaccurate to me. Not that I would ever want a power meter...
How does it know when your freewheeling though?
To be fair it should be able to work that out. If you know the gradient of any hill from the accelerometers and the wind force opposing the cyclist then it should be able to calculate a freewheeling speed for these conditions with its estimated drag coefficient. Since it knows the actual speed its simple subtraction to get the rider input part...but there is lots of room for error.
I think you do some kind of roll down test both ways on a flat road which must give it the basis of your drag coefficient.
Agreed, and either way I'd be more inclined to use PowerCal.
How does it know when your freewheeling though
Well if I were designing it, I'd have it measure your pedalling via the accelerometer on the basis that you can't pedal perfectly smoothly so a low frequency regular wave would indicate pedalling.
300 dollars, not going to be much cheaper than direct force PM's soon.
And unless I'm misunderstanding it, it wouldn't be any use on a turbo/rollers.
Correct.
Well if I were designing it, I'd have it measure your pedalling via the accelerometer on the basis that you can't pedal perfectly smoothly so a low frequency regular wave would indicate pedalling.
If I were designing it, I wouldn't design it 🙂
It's pointless, it's inaccurate - can only be used in a very limited set of circumstances and is at price point that you might as well get a proper power meter.
They would be better off re-factoring the guts of it into a CdA measurement device in conjunction with a power meter, then at least they have a potential to tap into a less exploited market sector.
And unless I'm misunderstanding it, it wouldn't be any use on a turbo/rollers.
I've got a big fan set up in front of my turbo so it should work fine 😉
They would be better off re-factoring the guts of it into a CdA measurement device in conjunction with a power meter, then at least they have a potential to tap into a less exploited market sector.
That would be very cool if you could somehow work it out from power, speed over ground and air speed.
The Ashton instruments one that goes into the BB seems a better bet as it's still about force not extrapolating all kinds of things from accelerometers and airflow.
That would be very cool if you could somehow work it out from power, speed over ground and air speed.
Should be fairly doable.
Have a google of chung method cda
The ability already exists to get wind tunnel resolution of CdA from road rides, but it comes with some caveats and is not particularly accessible without quite a bit of user effort, but there's no reason why it couldn't ultimately become some form of phone app.
^ Yep, it'd be a testers wet dream if they didn't call it a "power meter" but instead called it a "CdA measurerer", it would actually be pretty sweet if they came up with a separate ANT+ display once coupled with a PM. It'd take Garmin to play ball though unless they used their own headset, not sure why they don't do this anyway.
Wouldn't be a too bad to just do it with post processing of data files for testing kit, but real time CdA feedback on a head unit would be very nice indeed.
Looks pretty much the same as the iNewton power meters, except it's talking to a garmin rather than having it's own display/dataloger. and despite what the internet forum experts say, they seem to get good reviews in terms of accuracy, they're even recommended as the best budget power meter in the Allen/Coggan power meter book.
The iNewton works by measuring airspeed, speed over the ground, acceleration and gradient, and each time you coast it re calibrates the CdA value. It'll display it, but it only updates when you coast. If you combine an iNewton with a direct measurement power meter it displays real time CdA, which I suppose is cool if you're into aero stuff.
One thing that I always thought whenever people knocked the iNewton for not measuring power directly was, why is that a problem? If a position on the bike gives you more power but is less aero then the SRM/P2M/Quark/vector/stages is lying to you in just the same way, you're making more power but not going any faster, whereas the iNewton is more useful in the real world where what you actually want to know is "am I going faster corrected for gradient and windspeed".
It's made by iNewton, just their latest product, I didn't realise the iNewton head unit could connect to a PM though and get CdA, that's pretty sweet!
Here's a screen shot from a dude I know who's been messing with the iNewton.
[img] 
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The full iNewton head unit is mucho pricey though IMO.
One thing that I always thought whenever people knocked the iNewton for not measuring power directly was, why is that a problem?
Mostly practicality I guess. I'd assume most of the people buying such things are also going to spend a fair time on the turbo doing structured workouts, so they'd either then need another power meter. They could use a smart trainer with a built in power meter, or a turbo with a known power curve, but they still then need to come up with a method of transposing the different watts from the two different systems.
Brief (by his standards) review by DC rainmaker here - he thinks it is ok, and knows his power meters...
[url= http://www.dcrainmaker.com/2015/08/first-powerpod-power.html ]review[/url]