Power2Max NG ECO In-Depth Review


I know, you’re confused.  You’re thinking to yourself – didn’t he just review the Power2Max NG last month?  And indeed, I did.

But this isn’t the Power2Max NG.  It’s the Power2Max NG ECO.

Well, that’s a different beast.

The ECO is essentially Power2Max’s new budget lineup of power meters.  At about half the price of the NG (making it $490/490EUR with crank arms), it carries with it many of the same core traits of the NG, while skipping on some of the higher end features.  Quite frankly, it’s an incredible deal.  But let’s not get too far ahead of ourselves.

This unit was just announced this morning, but I’ve been riding one for a bit now with plenty of indoor and outdoor rides this summer, in rain and sun to sort things through.  As usual, I’ll hand back this trial unit to the Power2Max folks when I see them at Eurobike in a week.  With that – let’s dig into it!


First up is what’s in the box.


The box, in this case, looks an awful lot like the Power2Max NG box.  In fact, about the only difference you’ll notice is the little ‘Eco’ label on the white SKU sticker:


Inside, you’ll find only two items (three if you count the protective foam):


You’ve got the power meter spider, as well as the decorative stickers:


Here’s a closer look at the front of the unit:


And then the back of the unit:


And…that’s basically it.  Of course, your exact configuration may (and likely will) differ on which package you’ve bought.  There are a few different ones, some of which do include crank arms, here’s the low-down. Note that all prices are the same whether in USD or EUR.


Do note that every power meter has different compatibility nuances.  Some only work with certain cranks (mostly spider or crank arm region power meters), some certain pedals/cleat types (pedal based power meters), and others certain wheel configs (hub power meters).  Same goes for things like bottom brackets.  You’ll want to double and triple check your specific config, and in most cases I find these power meter companies are more than happy to confirm or deny whether your bike config is compatible via a simple e-mail.  For example, in this case, that the Power2Max NG ECO  is not compatible with Shimano 4-bolt spiders, though it is compatible with 4-bolt chain rings from Shimano.  So if that’s you – then you might need to either look elsewhere or consider changing things around.

Ok, with that unboxing out of the way, let’s get onto the installation.



Getting it installed will vary a bit and depend on what specific crank options and bottom bracket configuration you have and/or bought.  In my case, it was a super simple swap of ‘like’ crank types, so the whole process only took a few minutes to change out.  At worst, if you’re inexperienced in swapping out crank sets and chain rings, you’re looking at 20-30 minutes.  And in a best case scenario a couple minutes.

In my case I was swapping from the Power2Max NG…to the Power2Max NG ECO. Just a case of what happened to be on my bike last.  So that meant I needed to remove the crank arms first, and then the chain rings from the existing unit, and move them to the new unit.


With that all completed, I got to work installing the crank arm on the new ECO spider.


And then get the chain rings added back on:


Wondering how you tell the difference between a Power2Max NG and a NG ECO from afar?  One way, and one only: Power2Max NG ECO has a thicker battery compartment (since it’s coin cell), versus the thinned down cover over the USB re-charging port on the Power2Max NG.

DSC_8636 DSC_2147_thumb

It’s far easier once the lids are off of course:


Oh, and in my case, I had white stickers on it (versus no stickers on the other one).  That made it easy too.

From there I got the the unit attached to the bike, and plopped the left crank arm on as well:


Lastly, if you hadn’t done so yet, remove the little white piece of paper keeping the coin cell battery from activating.  I did so earlier in the process:


And thus, we’re done.

I’ll cover calibration and such in the next section – but you’ll want to do a zero offset at some point before you start riding.

General Use Overview:


Let’s start off with what’s different between the Power2Max NG and the NG ECO, since that difference basically saves you $500…or…doubles the price (depending on how you want to look at it).  And there’s no better way to do that than a simple table:


While I may not be an expert in these such matters – I’d say Power2Max pretty much just gave people almost no reason to buy the higher end Power2Max NG unit.  I wouldn’t.

So why don’t I care about left/right power balance (which the ECO lacks)?  Well because in the case of how the Power2Max measures it, it’s not real.  It’s actually not left/right balance, but rather whether you’re pulling up or not.  You can easily trick this by simply single-leg pedaling, and you’ll note the unit totally misses that.  Compare this to true left/right balance capable units like the Verve Infocrank, ROTOR 2INPower, PowerTap P1, Garmin Vector, Favero Assioma/Bepro, and so on – which actually measure the left and right sides.

As such, since it’s giving you useless power balance data – then it honestly doesn’t matter. Plus, I virtually never look at power balance data when doing ride analysis.  The only place I think that’s valuable today is injury recovery, and in that case you *really* want to have legit left/right numbers.

In any case, like the NG and all past Power2Max power meters, the ECO is silly easy to use.  There’s little to do day to day other than simply riding with it, as it’ll automatically turn on for you.  About the only maintenance you’ll need to do is to check the zero offset every once in a while to validate it hasn’t gone askew (though, I tend to do it every ride).  Still, it’s worth going through some of the ECO basics just to cover all the most common questions.

First off is that the ECO differs from the NG in that it doesn’t use the USB rechargeable battery, but rather the CR2450N coin cell battery which is the exact same as before.  It’s also what the FSA PowerBox uses (Secret: The ECO and the FSA PowerBox are the same thing).  With this coin cell battery you should get about 400 hours of juice:


The battery does sit below a rubber battery cap that honestly isn’t all that awesome.  I’d be concerned about leakage over time (or it even just falling off), so we’ll have to see on this one. It’s not exactly the same as the NG’s new battery cap (that I also dislike), but it’s secured slightly better than that is.

DSC_9270 DSC_9301

The ECO has a status light which will illuminate when you first rotate the unit, indicating it’s awake.

Next we’ll want to get the unit paired up to our head unit.  To do so we’ll simply search for the unit as a power meter.  Once found you can usually give it a name (like P2M ECO).

DSC_9272 DSC_9273

Note that the ANT+ ID is actually written along the edge of the spider, so you can double-check that at any time should you need to figure out (or confirm) which ID is yours.  You can see above how the ID shown above (50512) matches that of below.


The ECO also supports pairing via Bluetooth Smart, though in my case that wasn’t enabled on my unit.  So once Power2Max sorts that out next week at Eurobike I’ll validate it works the same as it did on the NG last month.  Given it’s the same code just enabled/disabled via firmware, I don’t expect any issues.  In that case I was able to easily pair it with the Fenix 5 & FR935 via Bluetooth Smart, as well as Polar’s M460 via Bluetooth Smart.

Like the NG, you should be aware that the ECO has a unique Bluetooth Smart pairing mode. This means that for the Bluetooth Smart side of things you have one minute upon powering on the unit (pedaling) for Bluetooth Smart head units to find the NG/NG ECO units for a new pairing.  If you were to try and pair a head unit 10 minutes later instead, it actually won’t find it.

When it comes to calibration, the unit supports doing a manual zero offset.  Zero offsets are valuable because they allow you to track what’s going on inside your power meter from a calibration standpoint. While most modern power meters will stabilize themselves with regards to temperature compensation and such, by tracking the zero offset you ensure that if something is amiss you catch it before it impacts your training/racing.  It’s sorta like that engine temperature gauge on your car – you can ignore it 98% of the time, but the 2% of the time that it lights up – you probably want to do something about it (and no, putting electrical tape over it isn’t the right something).

To complete a zero offset on the ECO you’ll find the calibrate button on your head unit, while also ensuring you aren’t placing any weight on the pedals/crank arms.


A few seconds later it’ll return to you a calibration value:


Note: I did have a handful of times where the unit would report a calibration failure error.  In talking with Power2Max, it sounds like it’s pretty sensitive to being absolutely still, and indeed, I found that to be the case.  You can still hand-hold the bike, but just make sure your pedals aren’t swinging around or such.  In other words – take 2 seconds longer before pressing calibrate.

The key with this value is watching for significant change.  You don’t want a lot of shift here, especially if the environment hasn’t changed.  Like the NG, the ECO will automatically perform a zero offset behind the scenes anytime there’s no force applied to the unit for at least two seconds.  This could be at a stoplight or when otherwise stopped pedaling.

When it comes to data recorded by the head unit, it’ll vary by protocol.  Here’s what each supports on the ECO:

ANT+ Power (total power)
ANT+ Cadence
ANT+ Power Balance (Only with paid software upgrade)
ANT+ Pedal Smoothness (Only with paid software upgrade)
Bluetooth Smart Power
Bluetooth Smart Cadence
Bluetooth Smart Power Balance (Only with paid software upgrade)

As an example, here’s a file recorded with an Edge 520 via ANT+ on the Power2Max ECO without the paid software upgrade.  And a screenshot from that of the relevant data sections.


Now before we dive into the power meter accuracy pieces, it’s notable to point out that at this point there is not yet an app for the Power2Max NG ECO unit.  That was certainly a major piece of having Bluetooth Smart, which would enable you to update the unit’s firmware more easily via your smartphone.  Other manufacturers like ROTOR, PowerTap, and Quarq also offer more detailed diagnostics and related data via the smartphone app.

Even more important for the ECO is that with this app you can pay the fee ($50/EUR) if you’d like to upgrade the firmware to support the handful of additional metrics that the NG has (specifically power balance).  Note that each function is $50.

Power2Max says it’s coming though, likely in September. At the moment it’s not a big deal either way, since you can still calibrate and such with any head unit.

Power Meter Accuracy Results:


I’ve long said that if your power meter isn’t accurate, then there’s no point in spending money on one.  Strava can give you estimated power that’s ‘close enough’ for free, so if you’re gonna spend money on something it shouldn’t be a random number generator.  Yet there are certain scenarios/products where a power meter may be less accurate than others, or perhaps it’s got known edge cases that don’t work.  Neither product type is bad – but you just need to know what those use/edge cases are and whether it fits your budget or requirements.

As always, I set out to find that out.  In power meters today one of the biggest challenges is outdoor conditions.  Generally speaking, indoor conditions are pretty easy to handle, but I still start there nonetheless.  It allows me to dig into areas like low and high cadence, as well as just how clean numbers are at steady-state power outputs.  Whereas outdoors allows me to look into water ingest concerns, temperature and humidity variations, and the all important road surface aspects (i.e. vibrations).  For reference, the Power2Max NG ECO has a claimed accuracy rate of +/- 2% (vs +/- 1% for the NG).  It also does not require any magnets for cadence, while also automatically correcting for any temperature drift. Both of these are pretty common though on most power meters these days.

In my testing, I generally use between 2-4 other power meters on the bike at once.  I find this is the best way to validate power meters in real-world conditions.  In the case of most of these tests with the Power2Max NG ECO I was using the following other units:

Favero Assioma DUO pedals power meter
PowerTap G3 hub based power meter
PowerTap P1 pedals based power meter
Stages left-only power meter
Elite Direto Trainer
Wahoo KICKR SNAP V2 Trainer
Wahoo KICKR Trainer

In general, my use of other products is most often tied to other things I’m testing.  Also, when it comes to data collection, I use a blend of the NPE WASP data collection devices, and a fleet of Garmin head units (mostly Edge 520/820/1000 units).  For the vast majority of tests on the ECO I just used Edge 520 & Edge 820 devices.


Note all of the data can be found in the links next to each review.  Also, at the end is a short table with the data used in this review.  I’ll likely add in other data not in this review as well, once I finish consolidating that data.  I’m a bit behind on getting data off some of my head units into folders.

With that, let’s get right into it and start with analyzing an indoor trainer ride.  You can view the Analyzer file here (as well as download the data itself), should you wish to look at the live view.  This was a TrainerRoad workout on a KICKR SNAP 2007 (V2) as controlled by their iOS app.


At a high level things look pretty good, though this was a relatively tame indoor workout with relatively flat chunks.  But that’s interesting though, as it provides a way to validate whether or not drift is occurring.  Let’s smooth things out a little bit and look more closely at some of the shifts in power as I go from easy to hard.


Here’s a shift from about 170w up to about 300w. You’ll notice all three units track very closely. Don’t fret too much about the gaps between them, the scale on this graph is really small – so those gaps in this case are a mere 3w once it stabilizes.  During the actual increase we see more variability, but that’s normal due to recording rates and update rates (usually a 1-2 second difference in sprints is expected).  So all is good here.

Again, as I come down off the interval, we see very similar results too:


I’ve done about 3-4 indoor workouts now on the ECO since late July, and all are the same.  I’ll add the remainder of these indoor sets next week, but at present they were using other unannounced products (ahead of Eurobike), thus, no inclusion here.  They included a variety of Zwift, TrainerRoad and manual ERG controlled workouts – and all of which were solid.

So instead, let’s head on outside.  This ride is cross city, and then some sustained power loops around a park for about an hour before returning.  This allows me to see if there’s any drift over a longer period of time in the park doing loops at a relatively steady state, as well as to see how it handles all the constant stops/starts of cross-city riding.  Here’s the Analyzer link.


First, let’s start with that nice 700w spike around the 13 minute marker.  I must have gotten excited chasing Grandma on a bike-share Velib or something.


As you can see, the three units track beautifully across that.  Even at 670w, there’s only a 15w spread between the three units, which is expected given they are measuring at different places.  And nicely, the PowerTap G3 is the lowest of the bunch, and the P1 the highest of the bunch – with the NG ECO right in the middle – perfect ordering.  Of course, one could argue whether one or the other should be a couple watts higher, but really – they’re all within the +/- 2% they’re claimed at.

The above graph is smoothed at 10-seconds, what if we remove the smoothing though?  Here’s that:


You’ll notice that the P1 and its head unit happens to take an extra second or so to see that pop, but then catches right up.  I haven’t see that before, so my guess is that it was just a random isolated interference thing.  In any event, even at 1-second sampling in the above graph, the units track really close (which is actually usually hard to show in a sprint like this).  Good stuff.

Let’s look at the stability of those loops I did for an hour (in a car-less area):


As you can see, it was like the three units were glued together.  Picking a random point around the 48 minute marker, we’ll look in more closely:


You do see a bit of changing of ordering here – but all of this is within a few watts of each other – and thus within the +/- 2% stated accuracy of each of the units.  But otherwise really nice.

Next, let’s go to another outdoor ride.  I like this one because it has a wide variety of terrain, including a beastly cobbles section.  Actually, two beastly cobbles sections.  Note, I don’t talk about all the non-beastly cobbles, since those are normal in Pairs.  But these two are among the roughest in the region – and ones I often use for testing/breaking devices.


Since we’ve established that steady-state is fine and stops and starts, let’s just go straight to the half-mile section of miserable cobbles.  The reason cobbles are worthwhile evaluating is that most power meters these days use accelerometers for cadence, and when cadence goes out – accurate power values soon follow to crapland.  Here’s me coming off the stoplight and into the cobbles:


Everything tracks pretty well.  A slight bit of variance from the P1 about a minute later for some reason, but it settles out shortly thereafter.  And if we switch to the cadence view, you can see why.  Remember – when cadence fails – power follows along with it:


But throughout this, the Power2Max NG ECO stays true and to the plan.

Within that same ride later on I did a 850w or so sprint, somewhat out of the middle of nowhere.  You can see the three units track very well – though as always the 1-second update rates make it look a bit blocky.


For those interested, here’s another ride from another hour-long ride.  Like the others, there’s no issues in it.  One quick way of spotting any abnormalities in comparative power graphs is to look at a mean-max graph, which shows the power values plotted over time duration:


Note that it’s totally normal at the sub-15 second range to see slightly more variation due to recording/transmission rate differences.

Overall I’m seeing exactly zero power accuracy issues with the unit.  Same goes with cadence.  This honestly isn’t too surprising, as there’s good reason Power2Max has become so popular in recent years.  They offer a tried and true solution that’s accurate and easy to use.

(Side note: All of the sets are analyzed using the DCR Analyzer.  This allows you to open the sets up yourself, look at the data, and even download the original data files for your own comparisons and analysis.  These days you can also use the DCR Analyzer for your own comparisons, more info here.)

Comparing the Power2Max Models:

Since publishing this post I’ve seen a ton of questions on the different models, in particular between not just the NG and the NG ECO, but also the previous generation Type S models (which are similar in price now).  Here’s a handy-dandy chart that may help folks, that I’ve put together:

Power2Max Model Comparison

FeatureNGNG ECOType S
PriceFrom $940From $490About $500
Battery TypeUSB RechargeableCR2450 Coin CellCR2450 Coin Cell
Battery HoursUp to 150hUp to 400hUp to 400h
Accuracy+/- 1%+/- 2%+/- 2%
Under the covers strain gauge designNG-styleNG-styleType-S
Power (ANT+)YesYesYes
Power (Bluetooth Smart)YesYesNo
Cadence (ANT+)YesYesYes
Cadence (Bluetooth Smart)YesYesNo
Power Balance (ANT+)Yes$50 via appYes
Power Balance (Bluetooth Smart)Yes$50 via appNo
Pedal Smoothness (ANT+)Yes$50 via appYes
Pedal Smoothness (Bluetooth Smart)Yes$50 via appNo
Torque (Bluetooth Smart)Yes$50 via appNo

So what’s the key takeaways here? Well, in my mind, if you’re trying to decide between the NG and the ECO, I’d almost always go for the ECO, unless you really…really…really care about some of the additional metrics (I wouldn’t, personally).  And if you did, you could buy them for $50 a shot extra (note: You get both the ANT+ & Bluetooth Smart variants for that ‘level’.  So if you buy power balance, you get both ANT+ & Bluetooth Smart power balance).

Then you look at the +/- 1% vs +/- 2% piece on accuracy.  Honestly, this is another area that I’m just not seeing it matter much to most folks to have that difference.  The power meter world is generally pretty good at +/- 2%, especially since most systems exceed that anyways (the +/- 2% is really a ‘worst case scenario’).  Most of these companies will explain they’re usually closer to +/- .5% in the vast majority of cases.  As I noted above in the chart (probably confusingly), the under the covers strain gauge aspects of the NG ECO is very similar to the NG, and not the Type S.

Next – the biggie – Bluetooth Smart.  This is the core reason I’d generally recommend the ECO over the Type S.  If you plan to use phone apps or Polar/Suunto head units/watches, you’re going to need Bluetooth Smart support.  So if you want to pipe your power into Zwift on an iPad for example – you’re gonna want Bluetooth Smart.  If on the other hand you only plan to use a Garmin or Wahoo device – then no worries.

Finally, battery design.  I’ve made no secret that I’m not a huge fan of the new NG/NG ECO battery cover.  I think it’s mostly stupid and prone to falling off.  I’ve had mine fall off indoors when I didn’t fit it right.  Now the NG unit is internally waterproofed anyway, so losing it in a rainstorm or twelve won’t hurt you. However, on the NG ECO if you lose it in a storm you’re hosed as the battery would be exposed (I’d yank the battery immediately).  Meanwhile, the Type S requires a screwdriver to change.  But again, that’s once every 400 or so hours.  So not that often.  If you rode 10 hours a week (a fair bit), that’s once every 10 months.

All that said – my general recommendation between those three models (crank compatibility items notwithstanding) is the NG ECO.  But as always, use the above info to figure out what works best for ya.

Power Meter Recommendations:

With so many power meters on the market, your choices have expanded greatly in the last few years.  So great in fact that I’ve written up an entire post dedicated to power meter selection: The Annual Power Meters Guide.

The above-noted guide covers every model of power meter on the market (and upcoming) and gives you recommendations for whether a given unit is appropriate for you.  There is no ‘best’ power meter.  There’s simply the most appropriate power meter for your situation.  If you have only one type of bike I’d recommend one power meter versus another.  Or if you have different needs for swapping bikes I’d recommend one unit versus another.  Or if you have a specific budget or crankset compatibility, it’d influence the answers.

Now I last published my annual guide last September, so some things have changed since then. Here’s the quick and dirty version of what’s been released review-wise since that time:

A) 4iiii Precision Dual System In-Depth Review
B) WatTeam PowerBeat Gen2 Dual System In-Depth Review
C) Quarq DZero In-Depth Review
D) ROTOR 2INPower In-Depth Review
E) Power2Max NG In-Depth Review

I’ve also got one more in-depth review coming up in the next week or so:

F) FSA PowerBox (here’s a first look)
G) Favero Assioma Pedals (aka BePro Gen2) – first look here

Of course, at this point we’re a mere week away from Eurobike – the epicenter of most cycling power meter announcements.  I expect some new products there, but not a huge number.  And maybe one at Interbike.  As such, I plan to release my annual power meter guide the week after Interbike in late September, as normal.  Maybe a touch earlier if I don’t believe there’s to be any announcements at Interbike.



In many ways, I feel like the Power2Max NG ECO is what Power2Max should have announced a year ago when they announced the NG.  And I’m specifically talking about the price here.  Given the significantly lower price than the full NG model, I suspect the ECO will completely cannibalize sales of the NG.  It takes the tried and true Power2Max platform, updates it slightly and stuffs Bluetooth Smart in it – making it more competitive with others, and in fact – incredibly competitive in the marketplace.  $490 for full and accurate power capture with both crank arms?  I’m not aware of anything in that range.

Do note though that the NG ECO is more akin from an accuracy standpoint to the Power2Max Type S – rated at +/- 2% versus the +/- 1% of the normal NG.  Not that I see that really mattering much, power meters for years have been rated +/- 2%, and there’s no real issue there for most.  Also, keep in mind it maintains the coin cell battery instead of being rechargeable.  I actually prefer that, but to each their own.  And of course unless you pay for the upgrade via the app it won’t show power balance.

Also note that the Power2Max NG ECO is the same unit as the rebranded FSA PowerBox.  Each company though sells slightly different crank arm configurations with them, but with the PowerBox you pay for the Bluetooth Smart power connectivity via firmware update.  You’ll see my FSA PowerBox review in the next week, though I’ll give you a spoiler: I’ve got no accuracy issues with it.

With that – thanks for reading!  Feel free to drop any questions below, I’d be happy to try and get answers for ya.

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  1. andy

    Any word on whether p2max is going to allow user-settable slope via the phone app?

  2. Dominique Lüber


    I saw you installed this power2max on a SRAM Force crankset. I have a question concerning the pin bolt (preventing the chain from falling between crankarm and chainset).

    I’m using the same setup with a power2max S Type. Which would be the easiest/quickest setup for adapting? Right now this pin is located on the opposite site. Somebody told me each chainset gets shipped with 2 pins. is that true?

    I know, a perfect aligned/installed front derailleur will prevent this from happening, but I had some occasions where this happened to me

    • Eric Schiller

      @Dominique Lüber

      SRAM now includes two pins on new Force and Red chainrings. If you buy the crank they probably just include one. I’ve adapted it before, you just need to put the ring carefully in a vice and use a small punch to hammer the pin out, and then carefully press it into the hole on the other side of the ring.

    • Tim

      Does the ECO use the three bolt retaining system on the SRAM cranks or the same 8 bolt as the Quarq?

    • Eric Schiller

      You can clearly tell from the photos that it is the 3 bolt system. SRAM has not really been selling the 8 bolt crank arms alone aside from OEM on some bikes.

    • Tim

      Ok let me be more specific then. Will it be available in SRAM 3bolt mount and for 1 X or 2x mtb drive trains? Currently P2M don’t have any SRAM MTB compatible

  3. Jeff D

    Great value unless you use a Campag groupset like me :-(
    I guess its a case of smaller manufacturing run size that makes it less viable and more expensive for tooling.
    Still interesting though, and I expect to see further significant price drops across the range of manufacturers in the next few months.

    Great review as always.

    PS. Still waiting to see the pics on theGirl’s wrist and unboxing video of the latest Suunto Spartan (not that you’re busy or anything!)

    • Sorry – gotta get that Spartan unboxing video finished (multi-cam/audio track things are a PITA). I took photos somewhere around here, will try and find and upload today.

    • Phil Buckley

      Yep – I was excited about this until I saw the €1390 tag for Campagnolo! I think we are stuck on the pedal-based meters for now, but always good to see new things coming out.

    • Alex

      Same for me – I would also love to see an affordable solution for my campa record

  4. mike Hensen

    OMG, game changer, imo

    • Yup, it’s a really solid deal. Sure, we’ve seen Power2Max in that range before on sale (+/- $50)…but that was often without cranks. To have this be the base price is solid.

  5. Nathan B

    I was just about to recommend this to a friend, then realised that it’s not compatible with Shimano’s 4 Bolt cranks.

    This seems an off omission from the review, considering they’re the most popular cranks out there.

    I tried searching for the words “shimano” “bolt” “BCD” and “compatible” and only got one result on the last word, which wasn’t related to what I was trying to find.

    I realise you can see from the picture, but still. Could save someone from making an expensive mistake by mentioning it.

    • Good point. I guess I’ve become used to the nuances that every power meter has some level of compatibility type issues. Just a matter of which issues matter to which people (oddly enough, four-bolt has never much mattered to me personally). But I’ll find a place to sneak it in.

    • Clearly communicating compatibility seems to be a big challenge for Power2Max. You can’t assume everyone who is interested in power meters is fluent in the language of cranks, bottom brackets, and bolt patterns.

      I contacted Power2Max support a few months ago to figure out which of their products would work with my bike (a Giant Defy 1 Disc 2016). The support team replied quickly and they were friendly, but still, it should be communicated more clearly. I shouldn’t have to contact support to figure out if I can use a product.

      The P2M support person told me I should use the “Rotor 3D” version of their product. Looking at the new list of ECO versions, I’m not confident if the one for me is the 3D+ or the 3D24. I’m sure their team would help me figure it out again, but it’s an odd layer of friction in their buying process. Perhaps they are forbidden from mentioning certain manufacturers for legal reasons, or something along those lines.

      Anyhow, this power meter looks excellent. Totally agree with Ray that this is the one I was hoping for last year.

    • The spider isn’t replaceable on Shimano so they have no way of being compatible

    • I think the compatibility thing is tougher than it might appear. It’s something that trainer companies also struggle with.

      The problem is that compatibility often starts to differ year to year. Especially around things like bottom bracket standards. What starts off as a simple question ends up spiraling into something far more complex. I think for big ticket items (like Shimano 4-bolt), it’s a bit easier with a blanket ‘no’. But where it gets messy is when the answer is ‘maybe’.

    • Tom

      Totally agree, I’ve been looking for a PM for over a year that I can use on my Ultegra chainset. I’m not super clued up on the world of bottom brackets so have been put off making a purchase. I get that it might be difficult but surely they are missing a massive chunk of the market. I don’t know numbers but would guess Ultegra must be one of if not the most popular set ups out there.

    • Regan

      If you use Shimano cranks at the moment they are likely 24mm cranks. The Rotor 3D is 24mm the same as a Shimano (hence 3D24) and is considered a straight swap. The 3d+ is different and is a 30mm crank.

      There is also GPX cranks which is 24mm on the drive side and 22m on the non-drive side, just to add to confusion.

      I only know this as I have just been through he same process and bought the NG with the Rotor 3D24 cranks.

      Personally I wouldn’t blame Power2Max for this confusion BB/Crank standards and what fits with what it overly complex with so many ‘standards’ from manufacturers.

    • Regan

      You can use Shimano Chainsets (Chainrings), they have a 4 bolt pattern available (I just bought one). what you can’t carry over is the crank arms as the Spider itself only mates to a range of cranks. It’s actually a decent range, but you do have to buy a new set of crank arms if you run Shimano. Personally, I just considered it the cost of change – it’s no different with most other powermeters.

    • Frank

      Giant = BB86. Inside diameter is the bearings = 24 mm. So, you will need the 3D24 version. The regular version has a 30 mm axle (will not fit, the hole is simply too small); the axle will also be too short.

    • Gerald Brown

      I am using a P2M with BB30 on my Giant Defy Advanced SL and also on my Giant Revolt 0, originally with 24mm shimano /GPX BBs

    • Marcelo Iannini

      Difference between Rotor 3D24 and 3D+ is that the first is for Shimano Hollowtech II bottom brackets, which have the 24mm spindle, the later is for BB30 (or BB386) with it’s 30mm spindle. If your cranks are Shimano, you can not go wrong with Rotor 3D24: just swap them out.
      Power2max is making these Rotor powermeter in both the older 5 bolt chainring and the newer 4 bolt chainring configurations. Order accordingly.

  6. Why is it so hard to find a crank power meter that fits the bolt pattern of 2016 Shimano Ultegra? I keep looking for a Power2Max or PowerTap unit that will, but can’t find anything! Am I missing something? And why are they all avoiding that Shimano bolt pattern?

    • Shimano cranks don’t use a removable spider so its not possible. SRM uses custom FC-SR70 cranks

    • Mathijs

      You can get the Quarq DFOUR. Installed it 2 months ago, and works with Shimano chainrings. Only had to change bottombrackets to GXP (22mm left, 24mm right axle) from a Shimano pressfit. But this was a easy job for my LBS. Since then, works great.

      Other options for total power: Pioneer, 4iii (only Dura Ace)

    • Steven


      That is because of the 1 piece design of the Shimano arms and Spider.

      You cannot get a spider based Power Meter into the crank like this. It’s just not possible.

      But you can Use Pioneer , 4iii or any of he left arm only companies out there.

    • Just as a minor point of clarification that the P2M folks just sent me via e-mail:

      “We do have a version for Shimano chainrings. It is the 110 4-S. Since Shimano cranksets are not modular and the crank arm cannot be removed from the spider the crankset cannot be used. But with our Rotor 3D24 or FSA Gossamer or K-Force light 110 4-S versions you can use the chainrings.”

    • Dr_LHA

      Yes, they have a version that works with Shimano 4-bolt chainrings. You end up with a weird looking crank afterwards though, mixing FSA/Rotor crankarms, Power2Max spider and the shapely Ultegra chainrings though!

    • Stuart

      Another vote for the DFour here – one DFour, one GXP bottom bracket, and everything is working smoothly. Apart from a bit of fun and games with the mechanic, there was no issue with getting it installed and operational. (He was convinced that it wouldn’t work; I insisted that it should and asked that he try. He got some pretty serious egg on his face from that one when everything fitted properly.)

      I think it may be a patent or trademark issue; possibly Shimano wanting more money than it’s worth for manufacturers to make such things? I don’t know. But I do agree that it’s more than a little bit annoying; just another reason why pedal power meters tend to be the default option, I suspect…

    • Don

      It’s not a trademark issue. The Shimano cranks simply don’t have a removable spider, so you can’t replace it with a power-measuring spider, which is what all of these are.

  7. Easy

    I have just purchased the S-Type two weeks ago and it costs at least 50€ more. Now I’m asking myself if I should have waited longer for the new model. Maybe you could explain a little more about your perspective on comparing the ECO with the S-Type. Thanks!

    • Jorick

      I’m thinking about this as well. The only difference with the type S (that’s now on sale) seems to be the BT smart connectivity as far as I can see. Maybe I’m wrong, who knows. As said by someone else, communication is not power2max strongsuit.

    • John Vance

      The type S has a less convenient but more secure battery cover. It also provides left/right balance and pedal smoothness. Furthermore, on several models right now, the price includes Praxis chainrings. $565 with shipping for the FSA Gossamer + Praxis chainset version.

  8. LittleSaul

    Most power meters are just for roadbikes. Is there any recommendation for MTB, specifically for Shimano XT?

    • Anton Peterson

      Unfortunately it is very limited. Stages power meter is the only one I think and it is left leg only (they still haven’t announced their dual sided power meter yet)

    • Fred2

      I put a PowerTap G3 disc hub on my MTB this year. It seems to be a good solution.

    • Don

      There aren’t going to be any options like this for Shimano XT since it doesn’t have a removable spider. All of these options are essentially replacement spiders with power meters built in. No way to replace the spider on XT, that leaves Stages as the only option, or just getting different cranks. The P2Max option with cranks is almost the same prices as a Stages crankarm anyway. You can always sell the XT cranks, they’re only a $99 crankset brand new, so you’re not losing that much. It’s not like it’s some really high end bling crankset. They’re certainly functional, just not worth crying over. For reference, Stages XT crankarm $580US, P2Max Type S MTB Rotor Rex 3 PM and crankset – $820US, so a $240 for two-side power. Plus you could probably sell your XT cranks for at least $50, well, that might just cover the cost of new chainring you’ll need, so yeah, $240 difference gets you two-sided power, but lacks BT. Most other options are far more (SRM, etc.)

  9. Jacques

    Thanks for another terrific review and yes, I’m kicking myself for having bought a P2M NG two months ago as I don’t really see anything of significant use that I’d be giving up with the ECO. C’est la vie (accompanied by the usual Gallic shrug). Also agree on the whole charger plug/battery cover issue. I complained to the Vancouver office of P2M about my concern on losing the cover during a wet ride (Québec weather….) and they sent me a couple of spare covers (no charge). I’m less of a fan of coin batteries however – on my old PowerTap – the low battery warning always seemed to come at the least opportune times – now, I use the same cable as for my Di2 charger and plug it in once a month or so. It’s a question of getting into a routine about it I guess.

  10. Ben de Wet

    Hi Ray,
    Quick Q. Any info on whether these will be available in 130 BCD? Checked their site, but couldn’t find the info. BTW, bought Powerbox recently, and it tracks nigh on perfectly with two different PowerTaps that I own, so quite impressed.

  11. Michiel

    I have a NG and I see in the differences table that it is a paid feature with the Eco, does that mean that in the near future it is possible to collect the torque data? This is now not possible for as far as I know… it is not send over in the garmin fit files?

    • Meredith Lewis

      You can always calculate the torque yourself if you want to. Power = Torque x rotational velocity. Therefore torque in Nm = Power in watts / rotational velocity in radians per second (easy to calculate from rpm).

  12. Nicolas

    I also get the “calibration failed” error a lot with my Power2max NG. It usually takes 3 or 4 calibration attempts before it succeeds. And it fails even if the bike is perfectly still and the pedals aren’t moving.

    • Markus

      Same here with my NG

    • Marcelo Iannini

      I usually get one calibration failed message. I find that the NG is different than the S-type in a few areas:
      1) Calibration always fails the first time. I need to unclip me feet from the pedal.
      2) It’s slower to start transmiting than S-type. After each stop, I need some 10-50 seconds for power to begin displaying (using Garmin 510)
      3) Sometimes, it’s found by my Garmin, but no power reading. Have to disable/re-enable to start working. Happened during a race, I almost lost the peloton forever trying to fix it (I’m watt-watching-addicted)
      4) It’s faster in refreshment once it has communicated. In fact, so faster that I thought I’ve changed the “average 3s power” to “instant power”. Now I’m used to it.

  13. Remco Verdoold

    Ray do you think there ever will be power meters for a triple configuration (not pedal based)? I can imaging this would be a good solution.

  14. Robin

    Sorry for the lazy question, Ray, but am I wrong in thinking that the NG ECO is equal to or better than the S type? They both have ±2% precision.

    • Frank

      NG is better, since the NG has BT-support (type S doesn’t). And you can replace the battery on the go, with type S you need a small Philips screwdriver.

    • jeff

      the S has no issue with water – though the battery screws are a pain they are confidence inspiring. The NG/NG Eco cover ……. less

  15. Mick

    Although the unit uses a CR2450 at 3.0V, is there any possibility of swapping in a 3.7V rechargeable LIR2450 coin cell? Stages in particular does not support this as there’s no built-in regulator.

  16. Keith Wakeham

    Mathematically, the PS and TE metrics can’t truly be calculated with a spider. In fact, torque effectiveness is impossible and PS would at best be similar to L/R balance on spiders (I.E: very inaccurate). So I’d love to see how these line up.

    So they are just trying to file in blanks for money?

  17. Ben

    Does the $50 open up all 3 upgraded functions or just 1 function for $50?

  18. Jonathan

    what about mountainbike? any new spiders for 1x? SRAM spider? Cinch spider?.. pretty please p2m.. power to the off-road people too :!

  19. Chris S

    Has P2M indicated when these will be ready to ship?

  20. Antonios

    Just bought a Type S with rotor 3d24 and Praxis chainrings for 680€ on their summer sale. I guess that’s 40€ than the corresponding NG eco without the (priced at 99€) rings. Apart from the type S being a bit heavier I think it is still a a better deal!

    • True, unless you need Bluetooth Smart support for your device (like a Suunto or Polar unit).

    • velobob

      I don’t think their summer sale pricing makes much sense now – I was looking at getting the Rotor 3D30 without cranks and the Type S on sale is $540US vs the NG Eco at $490US. The NG Eco includes bluetooth which I would like as well as my assumption that the NG Eco has other improvements over the older Type S that we may not initially be aware of as it is newer technology. Unless the Type S drops to less than the Type S, and at least $50 less, I would go with the NG Eco.

    • Marcelo Iannini

      Plus, when you have Bluetooth and your computer runs out of battery, you can turn your smartphone’s Strava and still have power metrics on your file for the end of your ride. This is what I like about having it!

  21. DC, would you grab Type S which is on summer sale now for 540 EUR or wait for this NG Eco?

  22. Mark F


    Thanks for the review. I notice you didn’t mention the weight of the power meter…Would you be able to check it out and let us know?


  23. I don’t understand the rubber battery-cover-flap design, feels like a step back compared to the Power2Max Type S battery cover. ;(

    • Frank

      True but there’s one advantage, you can change the battery on the go. For type S, you need a small philips screwdriver.

  24. Howard

    Hi Ray,

    Does it make sense to switch from a left side 4iiii Precision with Cannondale SiSL 2 to Power2Max NG eco with FSA chainring and crank? Please give me some thoughts as I am having a hard time to make the decision. Thanks a lot


  25. Christian


    do they support osymetrics chainrings?
    I’ve read, that some powermeter shows higher values with nonround chainrings because of rough angle velocity measurement.


  26. Brady

    Trying to decide on this (with Force arms) vs a Quarq Dzero Carbon. I get can get a pretty good deal on a quarq so with pricing aside what would you recommend?

    • Frank

      Battery cover of the Quarq is certainly better. Battery life is worse (approx. 200 hours). You can swap the battery on the go, and another advantage is that Quarq uses a very common coin cell (2032) which is sold at most gas stations. Other than that, not really must between them I would say.

  27. Geoffrey

    Hey DC thanks as always for the great reviews!!! I really don’t know how you do it. Anywho…what do you think of using this with my QXL rings?

    • Mike Zimmermann

      I’ve talked to P2M about this issue some time ago and I’m using Q-Rings for 2 years together with a Type S without any problem.
      Regarding accuracy P2M told me, that the irregular (uneven) chain-speed (e.g. the speed of one single tooth on a single revolution) compared to a even cadence while using an oval chain ring will lead to a constant calculation offset of your power.
      Therefor in reality my Type S, compared to a Powertap Hub, shows constantly 7% higher values while on standard Q-Rings. For QXL-Rings this would be even higher, but still the same over the whole range of power, cadence, and so on…

    • Rein

      Not sure how Mike got this information, but they Seems to track accurate with any oval rings due to their high sampling rate.
      link to dcrainmaker.com

    • L D A

      I was about to order a Rotor Inpower (left only) powermeter (long time Q ring user) but as this powermeter is in my budget I m hesitating. Any of you guys have experience with both? Can you “tell” the P2M to deal with a 7% offset so the values are correctly displayed?

    • Aero

      Sampling rate doesn’t have anything to do with accuracy when it comes to oval rings. They are sampling TORQUE at 50hz (which they claim is fast – but SRM and rotor are sampling at something like 200hz), with no mention of how fast they are samplying cadence/rotational speed. The only way to make a crank-based power meter accurate with oval rings is to calculate power at that same rate (i.e. take every torque reading x distance x 1/50th of a second) and average out those readings every second. an average of torque x distance/time readings around the rotation will give accurate readings.

      The problem is now that all the readings are averaged, then multiplied by the distance traveled in 1 second. This uses an average speed that isn’t representative of the varied speeds occurring across each pedal rotation when using an oval ring.

  28. Sounds like a great opportunity to enter the world of power meter.

  29. Hicham

    Hi Ray,

    Thanks again for the in-depth review. Always appreciated.

    I don’t think the left/right is completely useless just because it does not measure directly the real power per leg. I find it useful because it does measure how your symetrical my pedaling is: for the p2max device to give a balance of 50%/50%, not only you need to apply during 1s (ant+ sampling frequency) the same amount of power per leg but also distribute that power equally across both legs.

    o picture this, let’s imagine I only pull with the left leg and push with the right leg with the same power per leg (hard to do in reality), then a dual sided power meter with measure a balance of 50%/50% but the p2max would display 0%/100% (more 20%/80% in practice).

    Also the left/right balance does help you spot overtraining and injuries that are about to happen in a specific leg.


    • The challenge is that it’s actually not even doing that. In that situation it’s only evaluating the power coming off your right leg from a balance standpoint. And specifically it’s just evaluating your power as distributed on a ‘clock’ where anything between the bottom of the crank (6PM) and the top (12PM) as you pull is given to the left leg, and any power generated on the downstroke between 12PM and 6PM (going down) is assigned the right leg.

      Which isn’t to say that metric by itself isn’t interesting (it could be), but it’s not really true power balance. It’s just making assumptions.

  30. Mike Zimmermann

    Hi Ray,

    any word from P2M about the difference between T(emperature) C(ompensation) + on NG an TC w/o + on ECO?
    I’m currently (and happily) using the Type S and just refused to upgrade my secondary bike with the NG since the Type S isn’t available as no-crank-version anymore, so the ECO would fill the gap…

  31. John

    Do any of these support 30t or 32t small chainrings?

    • Marcelo Iannini

      No, with 110 mm BCD you can’t go smaller than 33t. Usually these chainrings are 34 or 36t, but you can find a few (stronglight and Specialites TA, i.e.) in the 33t.

  32. Patrick J.

    Hey Ray, clarifying question here. Do you know if the Eco is built on Type S technology, or on the purportedly refined NG internal measurement?

    I think you noted somewhere the FSA Powerbox (which, as you mention, is the same thing as the Eco) is built on Type S internals, and the Eco’s +/- 2% accuracy is what the Type S claims. But the Eco hardware looks the same as the NG hardware, so double checking.

    For what it’s worth, I’m a happy Type S user, and as such, a cheaper unit with the same guts would give some slight assurance as to consistency between devices, at least in theory …

    Thanks for doing these reviews!

    • Yeah, I went back to them about that today. They’re saying the NG ECO is more like a twin sibling of the NG, than it is of the Type S. Meaning that their earlier statements about the PowerBox vs the Type-S aren’t super accurate. The PowerBox and NG ECO are the same hardware units.

  33. Rob

    P2M has always been the best value option for anyone who already owns a SRAM crankset and wanted crank based power. Given that quarq isn’t backwards compatible with existing SRAM cranks, you could either buy a P2M and swap out your spider on your existing crank or spend twice as much and buy a quarq power meter and crankset. The second option just doesn’t make sense! Will this prompt quarq to rethink and bring out a compatible power meter for its parent company cranks or is it going to watch a truck load of business go the way of P2M as the price differential is just too much to justify the switch to quarq.

  34. Patrick

    Hmm, so about this Type S I bought LAST week…

    • Don

      At least it was on sale. There’s usually a reason for those great sales right before Eurobike/Interbike. Did you get one with the free chainrings? That was a pretty good deal if you don’t need BT.

  35. James

    2 questions

    – Is this type of pricing enough to start another step down in general for power meters?
    – Does that type of battery cover make this a non-starter for “rougher” uses such as cyclocross and tough mixed terrain?

    Great review as always. Loving that a high degree of power accuracy has become pretty much table stakes.

    • I think it represents about half a notch down. :) Not quite a full-notch (that would have been them going to $399), but solid.

      I don’t want to say it’s a non-starter, only because I haven’t tested those scenarios. I’d be more comfortable with it on the NG vs the NG ECO, because with the NG the USB connector is still internally waterproofed (just gotta get sand/etc out). Whereas with the ECO the battery is totally exposed if cap falls off and in rain you’re hosed.

    • Scott E

      Dielectric silicone is a realitively cheap and easy solution. Coatting the battery-compartment and cap will solve most harsh conditions from ruining a ride. Won’t solve a cap loss, yet still provides for a good water and debris barrier.

  36. Mark

    This is what I was looking for when the NG came out!

    Any idea if it’ll work fine with 1x gearsets (i.e. SRAM Rival/Force 1)? They say the non-Eco work with Rival and Force 22 (double cranks)

  37. Thomas

    Thanks for the review. Now, I’m toying with the idea of getting a new bike, maybe, but I’m also just really attached to my current frame (it’s only a cheap entry-level Rose Pro-SL from 2011, but in the insanely rare white/brown decal). That bike is an Ultegra 10-speed setup. So, question: Is that anything that has an influence on compatibility, or is it the same as what is said elsewhere for Ultegra?

  38. rodrigo delgado

    which is a better option this eco model or the favero single sided pedals you just had your first look at. i have a caad12 with cannondales hollowgram crankset so the pedals are an easier fit. im a enthusiast no races, just want to start using power to get better.

  39. Hi All-

    Given the number of questions comparing the NG, NG ECO, and Type S models, I’ve added a new section to the review. I cover the differences, as well as my general recommendations if you’ve narrowed it down to a Power2Max unit.

    You can find that in this section here: link to dcrainmaker.com


    • Easy

      Great, thanks!

    • Great, thanks DC!

      Now all I need to figure out if it will fit my 3DF cranks

    • StevenShaw

      Should do. Get the 3d+ version. The 3df/3d30 and 3D+ are exactly the same in terms of size.

      I have some rotor 3df cranks and am finally seriously thinking that of getting a power meter.

    • Marcelo Iannini

      Yes they will.
      It also fits nicely in the Rotor Flow. I have my NG on a Flow. Just make sure you follow all dealer manual instructions to adjust your front derailleur, if using Shimano 11 speed first generation: my cable was routed wrongly by Canyon and was almost rubbing the crank arm.

  40. Jimmy

    “If you plan to use phone apps… you’re going to need Bluetooth Smart support.”

    You don’t really _need_ Bluetooth Smart to use several apps on lots of Android phones. I’ve used Strava with ANT+ sensors on my HTC U11; it has ANT+ built-in. Every Galaxy Note phone has had ANT+ built-in, and all the Samsung Galaxy S phones since the S4 have had ANT+. Samsung even put it in their mid-range J series phones. And if you don’t have ANT+ built-in, you could even use a short USB OTG adapter with a Garmin (or other) ANT+ USB dongle. I did that a few times on an LG G4.

    Several apps support ANT+ on phones, too, including:

    Kinomap Fitness & Kinomap Trainer
    Endomondo Sports Tracker
    Run.GPS Trainer
    Wahoo Fitness Workout Tracker

    • Yeah, but most ‘muricans don’t use proper phones. What they instead have is an overpriced fruit growth with major compatibility issues that’s missing half the features all other phones have. But hey, they are still stuck in the 19th century with their imperial measuring system.

      Hence the huuuuuge need for BT.

      Why anyone would use their phone as a cycling headunit in the first place is a completely different question…

    • Fun fact: Most readers of the site are actually iOS, regardless of country – yes, even in Europe. It’s roughly 2/3rds iOS, 1/3rd Android.

      Totally get the sentence should say ‘iOS’, happens when I write things at the airport/airplane with no sleep. But other phones like Google Pixel don’t support ANT+ either.

  41. Kale Bushmeyer

    Looks like a great product, thank you for the review.

  42. Dave

    As a SRAM crank rider looking to maybe start riding with a PM… the ECO looks like an awesome way to go!

  43. Lee Gilchrist

    Hi Ray,. I am reading all your reviews on the current crop of Power Meters. I am torn between this Power2Max and the Favero Assioma.

    I want left/right balance probably at the beginning to see how The pedel but after that just a accurate display of power without the “Double the Left” approach.

    As a long distance triathlete I work on averages most of the time so having a average readout over a 50 mile ride will be what I am looking for most of them time.

    I also like the changeable battery as you will never get battery fatigue.

    What is your preference so far at the budget end of dual power meters? Are the Favero Assioma still best for bang for your buck and offering the most flexible solution?

    I live in the UK so prices tend to be more expensive than US equlivant☹️

  44. Sui


    Would you go for a “power2max NG” eco or a “quarq DZero” if pricing is on pair?


    • This is an excellent question. No wrong answer. Quarq has slightly higher accuracy (claimed) and 2032 batteries, which are easier to find. P2MEco has a greater selection of crankarms and slightly lower price.

      I have both Quarqs and P2Ms and both are great.

      – If I’m on a SRAM bike I would go Quarq.
      – Campy obviously P2MEco.
      – Shimano? Probably Quarq.
      – Undecided? P2MEco Rotor.

      Overall I probably lean towards Quarq based on customer service. Again, can’t go wrong.

    • Well, at the same price I’d probably go DZero. It’s got all the features of the full NG, except…not at that price.

      Obviously, as GH noted, if you’re constricted by crank arms, then that might drive the decision. And I’d agree with him that Quarq customer service is very solid.

    • Sui

      Thanks :)

      I’m located in Germany, so p2m would maybe be the easier choice in terms of service, but I’m running a SRAM Red and i think I will take the Quarq due to the optical line up.

      THANKS folks :)

  45. _tido_

    I have a non standard Shimano RS-500 50/34 Crank, and I would like to purchase a cranck base powermeter (because i have spd pedals).
    Does someone has a recommandation ?
    I am due to change the crank or using a Shimano 105 / ultegra power meter crank ?
    Any help is welcome !

    • _tido_

      sorry i meant I would like a crank arm powermeter

    • Antonios

      If you want to change the crankset anyways, a Power2Max Rotor 3D24 would just fit your current bottom bracket.

    • _tido_

      Tx Antonio.
      1/ For my personnal knowledge, what makes you conclude that it fits my current bottom bracket.
      Shimano website says Bottom Bracket for RS-500 is SM-BB4600 / SM-BB72-41B. I can’t find any of BB46 BB72 BB41 on the list of compatible Bottom Bracket on the Power2Max webstite.
      2/ If i go to that solution, am i forced to change the chain rig, or can I keep the one i currently have
      3/ are the right and left crank arm included ? Pics shows only the right crank arm, and i did not find the option for the left crank arm.

      I looked here and there on internet, and found that some people used the RS-500 with a stages 105 / 5800 crank. I might go with that option.

    • Antonios

      Shimano Cranksets for at least the last decade have an axle of diameter 24mm. Since you have a shimano hollowtech II crankset your bottom bracket bearings are for 24mm axle cranksets. the 3D24 has a 24mm crankset (hence the name). If you are thinking about this power2max, i think their sales people can also help you find the right model.

  46. Robert

    Is the SRAM version compatible with a hidden bolt Force22 set-up? From the pictures, Ray, you seem to have a NHB version.

  47. _tido_

    Tx Antonio.
    1/ For my personnal knowledge, what makes you conclude that it fits my current bottom bracket.
    Shimano website says Bottom Bracket for RS-500 is SM-BB4600 / SM-BB72-41B. I can’t find any of BB46 BB72 BB41 on the list of compatible Bottom Bracket on the Power2Max webstite.
    2/ If i go to that solution, am i forced to change the chain rig, or can I keep the one i currently have
    3/ are the right and left crank arm included ? Pics shows only the right crank arm, and i did not find the option for the left crank arm.

    I looked here and there on internet, and found that some people used the RS-500 with a stages 105 / 5800 crank. I might go with that option.

  48. Lars

    Great review. Does it work with scram red?

  49. Louis

    I have a Type S model and am considering switching it out for a NGeco model. I’m interested in if the data on the NGeco is also 3 seconds old before it comes up on the head unit? This is a little issue I don’t like in the Type S unit.

    Thanks for your reply and the review, awesome stuff!

    • Hmm. It was never three seconds old on the Type S. You have standard delays in transmission/recording, but in an absolute worst case scenario that’d be 2 seconds (one second for rotation-transmission, one second for display update) – but that’s the same for all power meters.

      I showed in my Type S review it’s identical across other units. Same here too.

  50. Martin

    So what’s the difference between this new NG Eco powermeter and the older Type S powermeter? They have a nice discount on the Type S (€679,- for Rotor 3D24 with cranks and blades). What, in your opinion would be the beter option, the much older Type S or the much newer NG Eco?

  51. David Manley

    Any word from power2max when the ECO will appear on their website?

    Weighing up between one of these on my new bike build over some assioma pedals – or something else that may or may not drop in price in the next couple of months!

  52. I dress in Europe and are undecided between this powe2max eco, quarq dzero or srm origin with pc8. I know that the three units have a different cost, but spending less then having poor after sales service maybe is not a good investment. Which of the three meters would you recommend me to buy? What is the best quality / price / reliability service meter?

    • I think you’re likely in a pretty good spot on service in Europe on any of those choices. They all have service centers in Europe. And honestly, it’s rare any of them need service.

      All of them are mostly equally accurate, though the P2M and DZero units have better temp compensation than the SRM does.

    • Denis

      Thanks ray, what do you think about this table showing the results on repeatability of the various powermeter measurements?

      https://thumbor-static.factorymedia.com/2GA6nFmNVe6m9LzUPvstuXryCgk=/678×238/smart/http%3A%2F%2Fcoresites-cdn.factorymedia.com%2Frcuk%2Fwp-content%2Fuploads%2F2017%2F08%2Fpower-meter-accuracy .jpg

      Quarq SRM and Power p1 seem to be better than the power2max

    • My problem with that table (and I’ve talked to the authors), is that there was actually no control over the devices used. Meaning, they don’t specify what generation devices many of the types are (i.e. a 7 year old Quarq vs a 1 year old one)? Nor did they have ownership of those devices or do static testing to at least baseline accuracy.

      It was sorta a collection of devices they could find from people, regardless of history.

      Don’t get me wrong – I think what they were aiming for is solid, but these little things kinda matter.

    • denis

      Very kind you have been very clear.

      So in conclusion, according to your opinion, the price difference between srm and quark or power2max does not correspond to an actual increase in the accuracy and reliability of the right power meter

    • Correct, zero difference in real accuracy there.

      The main difference between Quarq and P2M ECO is around the metrics at this point, and of course various compatibility type items (same as any crank unit).

      As for SRM, the price there is ‘just because’. There’s no longer a valid reason for the high prices, which is quite frankly why their market share has evaporated.

    • Denis

      Ok, but it is also true that srm has the advantage of having the pc8 and a fairly comprehensive analysis software. I also have the help center a few miles from where I live (but this is just a coincidence ;-)).

      I do not mean that srm is better, I’m just trying to figure out where to make the investment considering all variables like after sales service. Sadly I had a bad experience with garmin support for vectors 2 and in case of problems I do not want to find weeks without power meter.

    • I don’t really see the SRM PC8 as that competitive compared to modern head units. Heck, I’d argue the Stages Dash is more complete than the SRM PC8, and at half the price.

      As for software analysis – 3rd party apps are what most people use these days and they’re far more details.

      I’ve played with the PC8 a bit here and there, but never came away impressed. It’s just not competitive anymore. About the only reason even dealers can come up with for buying the SRM PC8 is ‘doesn’t lose data’, except, that’s really not the case for Garmin Edge units either these days (and in that very thread, someone lost PC8 data). Certainly comets hit people every once in a while, but loss of ride data simply isn’t something I hear more than maybe once a year from people these days. And again, Stages is doing fantastic stuff in the data-focused realm here.

    • Denis Taccola

      Ok if I decide to take a quarq meter to your opinion what is the cyclocomputer that I would suggest to match (polar m460, Elemnt Bolt, Garmin) I like a lot wahoo elemnt bolt? And how do analytics software? sorry if I ask you many questions but for me it is important not to mistake buying since I do not have great economic demands

    • I’d look at:

      Garmin Edge 520
      Wahoo ELEMNT Bolt
      Polar M460
      Stages Dash

      All will capture the data more or less equally, and without issue. The Stages Dash will give you the most flexibility (and most SRM-like) head unit for data display (up to 16 fields). Garmin will give you 3rd party apps on your unit. Wahoo will give you largely proper navigation, and Polar will give you more cash in your pocket since it’s about $100 less than the others.

      They’ve got tons of nuances between them, so check out the product comparison tool on the sidebar to figure out what makes the most sense in terms of the features you want.

      For software, there are tons of options. Free options include Training Peaks, Today’s Plan (free variant), as well as Golden Cheetah (totally free). Paid options includes Training Peaks, Today’s Plan, and many more. Plus sites like Strava.

      Polar and Garmin also have their own free platforms that will likely fit the bill to get you going too.

  53. Moritz Sauer

    Is there any information on when I am able to buy it?

  54. Simon

    Interested in one of these power meters though completely lost on the one(s) compatible with my bike – a (stock) 2012 CAAD10 Ultegra, 10-speed, BB30 with FSA K-Light cranks. Can anyone help me though this minefield?! Thanks.

  55. Guy C

    If this power meter is exactly the same as the FSA Powerbox, does anyone know if it’s possible to upgrade the Powerbox’s alloy cranks to something like the Rotor ones later on?

  56. thomas

    so … they build this nice item here and decide to leave the Shimano bikes out ? This is something I would put on the “cons” list so that people affected do not need to read further. Assuming that Shimano has a remarkable market share this is something which sounds strange to me anyway. However – I will just move on and look for another solution which is affordable for me. (max. 500$ )

    thanks D.C. for the great work and greetings from Germany

  57. Orus

    Are power balance and pedal smoothness useful ?

    Why do you “virtually never look at power balance data when doing ride analysis” ? It is not important to have a 50%/50% L/R balance ?

    In order to win a race, you don’t need to be symmetric ?

    Same question for pedal smoothness.

    If these data are useless, p2m ng eco is a bargain!

    • No, attempting to achieve 50/50% balance will likely decrease your overall power. Most cyclists have variable balance, it’s rarely 50/50%, especially over the course of a ride, different power levels, or fatigue levels.

      Thus, except for injury recovery tracking, it’s mostly useless.

  58. Orus

    Thanks for the answer.

    So if balance power is useless, it seems p2m NG eco is the power meter I need, because I want the cheapest solution for only one bike (don’t want left only power meter, 4iiii is more expensive for european riders and PowerBeat has some weaknesses).

  59. Flavio

    The power meter market will commoditize in a couple or three years. Sometime soon most high-end bikes will be sold with some power meter. It will be part of the groupset.

  60. Marcos E. Kurban

    Thanks for the post, very useful.

  61. Teemu

    I got mine yesterday. Someone might be interested about weights.

    Spider model Rotor 3d24, BCD 110-S (=to be used with shimano chainrings).
    Spider weight = 159g including battery.
    Total weight with Rotor 3d24 crankset (170mm) and 53/39 DA 9000 Chainrings = 779g

    • Orus

      Thank you for the information!
      The official weight for a DA 53/39 172.5 mm is 637g, so your new crankset weights 142g more.

      According to my computations (I don’t know if all my data are correct), the weight for Rotor 3D24 BCD110S + Ultegra FC 6800 50/34 chainring is 801g

    • Orus

      I got new data

      P2M Type S 110S 3D24 175mm = 653g
      Type S = 174g
      NG Eco = 160g
      Ultegra FC6800 50/34 chainring = 148g

      Total weight = 787g

      Ultegra crankset 50/34 175mm = 690g, so with P2M my bike will weight 97g more.

    • Teemu

      I did scale also the DA 9000 crankset. The weight was 630g (length 170mm and chainrings 53/39).

    • Orus

      Is it possible to use Shimano chainrings bolts or do you need to buy the ones from p2m ?

      Do you confirm the special tool for rotor 3D24 is not needed if you buy the crankset from p2m ?


    • Teemu

      You can use Shimano chainring bolts, no need to order a new ones. However Rotor 3D24 special tool you need to order (if you cannot borrow it somewhere). At least on my case the cranks and the spider were no assembled (I think on Europe there is no “professional assembly” option on order form what is possible on North America). Mounting the spider to Rotor 3D24 cranks is relatively easy and only couple of minutes task. To be also noted: a vise will help with mounting a lot (here you can get the idea: link to youtube.com).

    • Orus

      I don’t like hidden costs…

      Is it possible to buy the k-force light by replacing the bottom bracket (I have an Ultegra CrankSet) ?

  62. Marco

    I saw recently on the p2m website that both the cannondale version of the ng-eco and type-S are avaiable at the very same price, 590 euros.
    In your opinion, given this, what pm would you recommend? My concern in particular is due to the poor battery cover of the ng-eco version.
    Have you experienced any issues with the ng-eco battery cover since this review came out?

    I thank you in advance for your kind reply, cheers from Italy. Marco

  63. Kevin

    Thanks for the great review! Has the Bluetooth functionality been released for the Eco yet? My intention is to use this power meter for Zwift on an iPad/Apple TV. If it has been released, have you had any issues with the Bluetooth signal strength or intermittent drop outs?

  64. Chris

    Is it possible to connect Power2Max NG ECO with Polar V650?

  65. Andrew Thomson

    I’m recovering from knee surgery and developed a leg imbalance. If they offer the $50 upgrade to see what each leg it doing is this worth it? If you don’t which crank based system would you remcommend for me?


  66. Hi great review, I am interested to buy a powermeter, my computer is Polar v800.
    Is it possible to connect Power2Max NG ECO with Polar V800?

    Do you recommend Power2Max NG ECO with K Force Light or Power2Max NG with FSA Gossamer?
    I am road amateur and my budget is about 900 $

    Thanks for your help

  67. Casey

    Wanted to let everyone know that the power2max customer service has been exceptional (thanks Michael & Evan). I had numerous questions to ensure I was buying what would work on my bike, and email replies were flowing fast–even on the weekend. I just had the NG ECO installed and everything was exactly what my bike needed.

    Note that the stickers are 3D and shiny, they look a lot better that the ones pictured above.

    I haven’t used it yet, but looking forward to it. Thanks for the detailed review – really helped in my final decision.

  68. JensFeed

    I bought a NGeco. I am very satisfied with how it works. Unfortunately, I have a little problem with the batteries. After a very short time (10 hours use), there is the Baterie warning from my Garmin. Does anyone have the same problem?

    • NGEco User


      I have got same notifications than you: Battery level low on garmin head unit. On my case I have seen the warnings on “cold” weather (like +5 degrees of Celsius). I do know that cold can affect to batteries but is +5 degrees of Celsius too cold.. I have contacted p2m support and would like to propose you to do the same that they get input more than one user only :)

    • JensFeed


      I also contacted the support.
      I got the message from the weak battery outside (8 °C) and inside (17°C).

      I measured the voltage of the battery = 3,09V Maybe it’s a mistake from Garmin?

    • NGEco User


      I also measured the voltage when doing indoor training. Before ride the battery voltage was 2.95V and right after ride it was 2.85V. Battery was inside Power meter when I measured it. I did rode 1h03min.

      I have not got any low battery warnings during indoor training’s but to be said those indoor sessions has been maximum 1h20min.

      Need to ride more and see how the battery is really lasting.

  69. Evin Kaless

    Yes! I have contacted P2M regarding ‘low battery’ notifications after just 48 hours after installing a new battery. They initially told me it was just some bad batteries. I replaced the battery the night before a ride. Battery status was ‘new.’ The next morning before the ride I checked again and the status changed to ‘good.’ The next day I checked before a ride and it was down to ‘okay.’ About 1.5 hours into the ride I got a ‘your power meter battery is low’ warning.

    Long story short – P2M now says the there’s an error in the software that is telling the Garmin that the battery is low when it isn’t. How on earth does something like that not get found in the very earliest stages of testing. Seems very suspect IMO.

    It doesn’t end there for me: I’m also getting power & cadence drop-outs at regular ~1 min. intervals. The whole thing has been very disconcerting.

    • Evin Kaless

      BTW, I’m a Type S owner and have been very happy with it which is why I jumped on the NGeco.

    • NGEco user

      There seems to be power2max beta app on play store (for android users). Also noticed some webpage: link to apps.power2max.com

      Let’s see if the new firmware is goming soon. Some FSA Powerbox users has also reported battery and dropout issues (garmin forum). I haven’t have a single dropout issue so far.

    • Gasman

      P2M are wrong. The low battery warning isn’t false. Keep using the low battery and it will be completely dead within about 20 hours of use. That’s some way short of their claimed 300+ hours. For some reason the Eco is draining battery power rapidly, just like those awful Stages units do too.

  70. Russell

    So just to confirm, how does one perform firmware updates without an app? Do they have a PC application?

  71. Evin Kaless

    Ray, you tested the NGeco with the Edge 520 and had no issues. Myself and others are having issues with cadence & power dropouts occurring a ~ 1 minute intervals with the Edge 520. Is it possible it due to the latest firmware (12.30)? Do you know what version your Edge was on at the time?

    As has been mentioned earlier there is also an issue with the battery status incorrectly indicating low battery. But P2M has already told me that they found the cause of that in the NGeco’s software. If that’s the case then I don’t see how you did not run into the issue in your testing.

    • NGEco User

      I’m using Edge 820 with firmware 8.50 and I have not seen any dropouts (to be honest, I have seen one when Garmin did reset ALL the sensors: speed, hr, power and cadence, so I do not count that). Also the same was with firmware 8.40, no power or cadence dropouts at all.

    • I don’t see any dropouts (and I’m riding with an Eco still on a test bike every other day), data is solid, all with an Edge 520.

      As for battery, I had seen a few low battery alerts, but didn’t think much of it. Mostly because I like to test the battery to death, so I just kept on using it waiting or the battery to die. As others have noted, it’s not actually every time, and I’m horrible at remembering the battery alert 2-3 days later until I’m outside ready to start my ride…at which point I forget again. Had it been the peak of indoor trainer season, I’d probably remember.

      While it’s a bit of an annoying bug now, it’s one of those bugs that bugs you for about 2.6 seconds, and then you forget about (like the PowerTap P1 ‘Right pedal error’), given how long the battery life on the unit is (400 hours), most people wouldn’t have to worry about whether or not it’s real for a really long time.

    • Evin Kaless

      Is your Edge on firmware 12.30?

    • Ahh, very interesting – good catch. Just looked at Sunday’s data set (I had uploaded it to the Analyzer, but not looked at it yet). Yup, with 12.30 on the Edge 520 it looks like crap:

      With my previous ride on 12.20 it looks good. I had upgraded the day or two before. :(

      12.20: link to connect.garmin.com
      12.30: link to connect.garmin.com


    • NGEco User

      I agree with the low battery warnings. It seems to be an bug in p2m software but the battery life is still ok (but too early to say that).

      I just updated p2m firmware with android app. Let’s see does it help the situation.

    • Evin Kaless

      Any chance you can get Garmin to look at this issue any faster than the average user? Or, suggestions otherwise? Can we revert back to 12.20?

    • I’ll poke them.

      As for firmware updates, all historical firmware versions are here: link to gawisp.com

      I’ll likely roll back as well. Just drop the GCD file in your ‘Garmin’ directory via USB.

    • Gasman

      P2M are wrong. The low battery warning isn’t false. Keep using the low battery and it will be completely dead within about 20 hours of use. That’s some way short of their claimed 300+ hours. For some reason the Eco is draining battery power rapidly, just like those awful Stages units do too.

    • I have reported the power dropouts to our engineering team for investigation. Thanks for the feedback.

    • MCA

      I rolled back to 12.20 and the dropouts are still present – every 55-60 seconds. Can’t update the firmware for the power meter either – app crashes when I attempt to do so. Profoundly annoying.

  72. Sumit Jain

    I just got mine today! I am using 920XT as my head unit. There is no calibrate option I could find. Any tips on how to calibrate and how often and when (just before a ride etc..) to repeat the process ?

  73. Dennis

    Can you calibrate the powermeter with the polar m460?

  74. Gasman

    I’ve been using an NG Eco for about a month now, and in that time I’ve clocked up about 450 miles, and I’m already on my third battery!

    When my Edge 820 warned me that the original battery the Eco shipped with was low after maybe only 5 hrs use, I put it down to a duff battery. When the second battery (which I’d ordered as a spare from P2M) did the same, I contacted P2M and was told that they suspected a bad batch of batteries. Oliver at P2M adviced continuing to use that battery until it really was dead and then to switch to a premium brand. I probably got about 20 hrs out of that second battery until the power readings became a bit erratic, and when I checked it with a battery tester it was indeed flat. So I was confident the problem wasn’t the PM or the Garmin head unit incorrectly reporting a low battery.

    Today I was out riding with a new Duracell battery, and after 5 hrs use at most I got my first low battery warning!

    So the problem isn’t the batteries and it isn’t a false warning. The problem is the PM draining perfectly good batteries quickly.

    I’m very frustrated by this as the Eco is my third powermeter in the past 4 years. My first was a Stages first generation unit which suffered from the well documented battery consumption problems. This was repalced under warranty with a second generation unit, which ate 4 batteries in 8 days. When I got a refund for that I switched to a pair of Powertap P1 pedals. These suffered with the well documented play in the bearings, as did their warranty replacements. I persevered with the replacements until after about a year the left hand pedal began to rapidly drain batteries too. I sold the next set of warranty replacements immediately and switched to P2M because of their supposed reputation for reliability!

    What the hell is going on here? I’m not hard on my equipment, infact the care I take over my cycling equipment is a frequent source of humour in our club. Without wishing to diminish in any way the excellent work Ray does with his reviews, it is obvious to me that the manufacturers of these PMs seem to be able to supply exceptionally reliable units for Ray to test, yet when supposedly identical units are used by ordinary riders they fall far short of their claimed reliability.

    If anyone from P2M is reading this; until it’s sorted out you should be providing your affected Eco users with a lot of free batteries!

    • Robin

      There’s no evidence to support the notion that manufacturers–in this case P2M–are cherry picking which PMs they send to Ray. There’s no upside to doing as much if a manufacturer knows there’s an issue with their product. The more likely scenario is that Ray’s experience with a given power meter is an n=1 sampling and thus may not be statistically representative of the whole population of a certain power meter.

      There’s nothing in P2M’s history that would suggest they engage in such dodgy behavior. If there is an issue with the hardware or firmware, it’s likely that it just wasn’t uncovered during development and testing.

    • Aaron Coady

      I’ve got a 2 week old powerbox, which is just a rebranded ng eco. I had a few dropouts where the power/cadence disappears from my garmin 920 for a short period of time and them comes back. It happens infrequently, but is still annoying. I’ve only used it ~6 hours.

      I tried the new app and it immediately told me there was a firmware update available. When I try to update the firmware it say the battery is empty and I need to charge it before I can update the firmware. When I start the app it has >80% battery, and then when it forces me to the upgrade screen it says the battery is 0. If I restart the app it says the battery is again in the 80s and then when the upgrade is prompted it says battery is at 0.

      The power meter seems to be working well other than these dropouts, but I’m worried about the battery consumption, and the inability to update the firmware.

    • Gasman

      Well given how easily several people on here (including me) have uncovered the firmware issue (i.e. just riding with it for a few hours) the manufacturer’s own testing procedures can’t have been particularly rigorous!

    • Quite simply, it sounds like you’ve got a defective unit. While others have pointed out low battery (but fake warning) issues, nobody else has stated theirs in burning through batteries at the rate you’re noting.

      I’m on the same set of batteries I’ve had on it since July or so. Obviously, I’m not riding that bike every day, but it’s there and low battery bits I ignore aside, it’s still the same battery.

      As for battery testing – no doubt, P2M should be doing that. It’s relatively trivial for them to do so since I know specifically they have the right rigs to let units run constantly.

      As for me, I’m generally aiming to test low-battery claims (i.e. 20 hours or 50 hours) to the best of my ability. But frankly, I won’t be able to test a 400 hour claim on many devices. I lack the riding time to do that (that’d be 10 hours a week of basically a year), and I don’t have (at this point) any sort of automated test rig for that.

      I have no doubt some companies try and send me better units, but I find that rarely works out. Heck, even P2M as noted here sent me the wrong firmware as noted above which didn’t have the BLE piece enabled. And ROTOR, well, I still saw issues. As for wrist units and other watches, most of those I get later through other retail places – so that takes care of that too. Same with trainers.

    • Jelle De Bock


      I had the same problem today during my ride. I had regular dropouts every minute or so and the battery showed critical. Others mentioned something about a Garmin update which could be the possible cause, but as a Wahoo Elemnt Bolt user I can confirm that the problem is also there. And I understand your feeling, I went through 4iiii precisions this year which both died.

  75. Aaron Coady

    I posted on Monday about not being able to use the android power2max app to update my FSA powerbox due to it indicating my battery was at 0 during the update stage but >80% during the startup of the app.

    I replaced the battery with a brand new Renata battery last night and it reads 100% during app startup, but 1% @3.1361V when attempting the update. As shown in the screenshot (serial number removed).

    I emailed power2max support Monday, and gave them this update this morning, but I haven’t heard anything back.

    Is there any other way to update the firmware?

    • NGEco User

      Maybe that problem is on power2max mobile app, I think it is still a beta release? 3.1V is a full battery.

      My NGEco battery voltage was like 2.9V when I updated a firmware with success.

    • Aaron Coady

      Thanks. How did you update the firmware? Is there another way?

    • NGEco User

      I was using the mobile app. The firmware update process was successfully done without any warnings. If you have not got any instructions from p2m support I would personally do the classic uninstall and install again action for the mobile app.

  76. Kipp Carlisle

    Hi Ray,

    Any updates from P2M on the launch of the iOS app? Would be nice to have for sure now that’s I’ve got the powermeter …. and seems really strange that they are not addressing on their website.