Anybody have insider knowledge on this? If their other products pricing gives a hint, perhaps if my be the most affordable PM.
I like my HR monitor, and had good success with thier speed/cadence sensor, but that’s not good.
I’ve seen several power meters on Ali Express and Alibaba; none of which I want to spend several hundred dollars on until I’ve seen one in person.
Carbon wheels and frames? Yes.
Electronics? Not so sure yet.
I like my HR monitor, and had good success with thier speed/cadence sensor, but that’s not good.
https://www.coospo.com/faq-power-meter/
Sorry, I don’t understand. Why is this bad?
Only 1000w maximum? That’s not a huge number, with many folks easily able to exceed that, so what happens when you hit the top of the range?
Assimoa for example says they go up to 3000w
Most mortal cyclists can get above 1,000W in a sprint, if only briefly. Strong cyclists can sprint above 1,000 for several seconds. So, if the max power it can measure is 1,000W, my first thought that comes to mind is how accurate is the PM as it approaches its limits? It is probably fine for steady time trial efforts, but it might start to fall down a bit on attack & sprint efforts.
From an instrumentation view, a 1000 watt range puts most users in the nominal range of the device instead of the very low end. It’s not going to damage the device, it’s a crank arm or spider and we’re not going to rip the gages off of it.
Edit: The range of the device has more to do with the amplifier than the gage.
I don’t try and measure 50 psi with a 1000 psi transducer, I would pick something around 100 psi and not worry about the spike.
But you are assuming that accuracy is constant until it nears its max rated limit. Do you know if a PM behaves this way. A audio amplifier, for example, has non-linear distortion as it approaches its upper limit.
But you are assuming that accuracy is constant until it nears its max rated limit. Do you know if a PM behaves this way. A audio amplifier, for example, has non-linear distortion as it approaches its upper limit.
Per jaretj, any reasonable selection of gage, amplifying circuitry, and a2d sampling device should result in force measurement accuracy that’s pretty much constant across the usable range (and then some extra beyond that).
This is my experience with strain gages (in an application different from PMs, but not that different).
Metal strain gages are a pretty mature, well-behaved set of devices in general.
Of course the engineering can be done incompetently. That has happened from time to time.
I wouldn’t trust jaretj to engineer a Zwift scale, though.
PMs are REALLY hard to get right. Even companies like Shimano and SRAM have versions that reviewers like GPllama and DCR have significant issues with. I wouldn’t get a PM from any company until it’s been vetted both by reviewers and the marketplace. The Asiomas are a good example of a PM that has been well validated.
But you are assuming that accuracy is constant until it nears its max rated limit. Do you know if a PM behaves this way. A audio amplifier, for example, has non-linear distortion as it approaches its upper limit.
Per jaretj, any reasonable selection of gage, amplifying circuitry, and a2d sampling device should result in force measurement accuracy that’s pretty much constant across the usable range (and then some extra beyond that).
This is my experience with strain gages (in an application different from PMs, but not that different).
Metal strain gages are a pretty mature, well-behaved set of devices in general.
Of course the engineering can be done incompetently. That has happened from time to time.
I wouldn’t trust jaretj to engineer a Zwift scale, though.
You can’t use a 50 ton scale to weigh people? 
I’d be mildly interested.
Their HR sensor is rock solid, way better than any of the Garmin/Polar ones. FFS, it survives battery replacements!
But you are assuming that accuracy is constant until it nears its max rated limit. Do you know if a PM behaves this way. A audio amplifier, for example, has non-linear distortion as it approaches its upper limit.
The torque cell is linear throughout it’s range not because the signal from it is linear, but because it’s been characterized through a multi-point calibration.
An analog audio amplifier is subject to the transistors you use, if you stay between saturation and cutoff voltages it will operate just fine. A digital amplifier will be characterized from the A to D so the entire range should work correctly.
Like the transistors in an amplifier, the strain gages in a torque cell need to be chosen for the correct range. Measuring the signal in it’s nominal range (near the middle) normally gives the best results. I don’t know if this power meter uses the same gages as similar ones we see here often, but if they are copying something they are probably using the same gages and different electronics.
Choosing to only read up to 1000 watts is likely an A to D conversion that the manufacturers chose arbitrarily and in my opinion, the correct choice for their market. It gives a better turn-down ratio for the system. I can see where that may be argued as there is evidence for and against raising the range.
Don’t worry, that’s the triathlete model. I’m sure the roadie model goes to 5,000 watts.
Joking aside, I’d be super reluctant to trust one of these. I believe that GPlama finally gave a good review of the Sigeyi PM, but it was a really long time coming before they got it right.
The way industrial elements and transmitters work, until you get a really big multiplier difference on the measurement range between two devices measuring the same thing…the accuracy within range for identical sensors that are close will be the same.
So it makes zero sense for them to cap the measurement range at 0-1000 (or probably 50-1000) versus going with 0-1250.
If they chose 0-1000 instead of 0-10000, then yes, it could matter. But that 250w or 500w difference to get you into a more realistic range, no idea why.
Also can’t imagine strain gauges in this marker cost that much different for that difference. If so, someone pencil pushed the decision to save 1 cent per unit.
I’d be mildly interested.
Their HR sensor is rock solid, way better than any of the Garmin/Polar ones. FFS, it survives battery replacements!
Same, but for my MTB and not road/tri. I confess I don’t understand what the engineers on this thread are talking about. But I trust they know a LOT more about this than I do. For sure, a good DCR/GPLama review (where they can dummy it down for me) would seal the deal for me.
In general, in technology - sports and otherwise, I find strong correlation between when companies screw up wording/little stuff, and when companies screw up deeper stuff.
It’s exceptionally unusual to list a max wattage of 1,000w - in fact, I’ve never seen that before for either power meters or trainers. That seems a rather arbitrary number. First, because I’ve never seen it. But second, because usually the limiter for most companies claims isn’t the underlying tech, but rather, the automated system they use to test them. Now, these systems have plenty of issues, namely in that they suck at being real, but they do validate things in a clinical-pretend lab setting. And the picking of 1,000w seems to imply to me such a test hasn’t occurred. Instead, it seems to imply they put a random cyclist on a bike, and they got to 1,000w, and impossibly, some other power meter matched that.
Third, generally speaking, these components don’t stop measuring at 1,000w. If it did, it’d concern me too.
Look, I’m not saying it’s not accurate - but, to me, it’s just such a weird claim. And every time we see weird power meter claims, things end badly.
In general, in technology - sports and otherwise, I find strong correlation between when companies screw up wording/little stuff, and when companies screw up deeper stuff.
It’s exceptionally unusual to list a max wattage of 1,000w - in fact, I’ve never seen that before for either power meters or trainers. That seems a rather arbitrary number. First, because I’ve never seen it. But second, because usually the limiter for most companies claims isn’t the underlying tech, but rather, the automated system they use to test them. Now, these systems have plenty of issues, namely in that they suck at being real, but they do validate things in a clinical-pretend lab setting. And the picking of 1,000w seems to imply to me such a test hasn’t occurred. Instead, it seems to imply they put a random cyclist on a bike, and they got to 1,000w, and impossibly, some other power meter matched that.
Third, generally speaking, these components don’t stop measuring at 1,000w. If it did, it’d concern me too.
Look, I’m not saying it’s not accurate - but, to me, it’s just such a weird claim. And every time we see weird power meter claims, things end badly.
If Coospo is reading this, they now know there’s only one way to our pocket books. We need DCR review validation.
I’d be super interested in seeing a review on the whole damn Coospo line up. I’m very blue collar and despite my recent splurging on a Fenix 6 it’s not likely I can afford multiple power meters for multiple bikes. Or upgrading my on wheel trainer for direct drive. But recently buying a Coospo Hr and cadence sensor these things are so good it makes me mad I ever bought anything else. Granted I’ve only had them a week but solid is the perfect way to describe them at this point.
I think I would wait for the LamaLab report or stick with Power2Max affordable and accurate.