BR Solution

4iiii Precision Energy Meter In-Intensity Evaluate


It’s been about 8 months since 4iiii started transport their Precision energy meters to patrons, which is a small pod affixed on your crank arm.  When the corporate introduced their front into the marketplace in September 2014, they’d deliberate to debut a self-installable choice for each left and correct legs.  Alternatively, each had been placed on grasp whilst they to start with rolled out their first model the place you ship on your crank hands.

The primary attraction to the 4iiii product is the low value – from $399USD for the formulation, making it the most affordable direct pressure energy meter in the marketplace.

Now, as common readers know – I first gained a unit again within the spring, alternatively, I had headaches getting correct energy.  I then gained a substitute with the similar problems.  In the long run, it might take just about 6 months for 4iiii to kind out why my explicit pedaling taste used to be inflicting accuracy problems, which they’ve now solved.  For lots of (in all probability maximum?) others, there have been no such accuracy problems noticed by way of then.  However, throughout that period of time, in lieu of a assessment, I up to date all present 4iiii posts with caution banners of the issue I used to be seeing.

All of which brings me to now – about two months after receiving what I’ll merely seek advice from as a Gen2 unit.  It seems just about equivalent, however does include up to date firmware (which all earlier devices gained), in addition to some tweaks to the pod and set up procedure to deal with the problems I noticed.

With that – let’s dive into issues.  Oh, and sure, as at all times the trial unit will return to 4iiii right here in a while.


First up is getting the crank out of the field.  Now remember that the crank arm in my field will vary from the crank arm on your field, since you would have despatched on your personal crank arm.  So, that is after you’ve despatched on your crank for attachment.  How it works is that you simply purchase the 4iiii Precision unit, after which as a part of that you simply’ll send your crank arm to them (they pay for transport each tactics).

So as soon as it boomerangs again to you, you’ll be status round with a nifty packaged up unit:


From there, seize your nearest Ikea knife, and slice away:


Inside of you’ll to find some paper goodness on most sensible.  This may be a small guide, in addition to details about your explicit Precision unit.


Moreover, you’ll to find two stickers.


Underneath all that you simply’ll to find the crank arm all packaged up, as smartly two CR2032 batteries (thus supplying you with one spare).


Now’s as excellent as any time to position the battery in.

In spite of everything, right here’s a better take a look at the crank arm all undressed:





The pod provides 6g of weight with out the battery, and 9g of weight with the battery – on your crank arm.  In different phrases, principally not anything.  With that, let’s get onto set up and configuration.

Set up/Configuration:


The set up of Precision is somewhat immediately ahead – particularly in case you already got rid of your unique crank arm.  If a pal/store did the removing of the crank arm, then you definitely’ll most likely need to go back to them for his or her products and services, as you’ll want the similar equipment.  The precise equipment will range relying at the explicit crank arm sorts and connection issues.

In my case, issues are slightly simple.  Right here’s my start line:


From there, I’m merely going to glue the left crank arm onto the spindle:


After which tighten it down in keeping with spec.  For those who don’t know the precise torque necessities of your crank arm, I extremely inspire you to seem it up – as it could possibly and can affect accuracy.  Merely cross ask Mr. Google to your crank arm guide, it’s at all times indexed within the first few pages.


As soon as that’s all achieved, you’re able so as to add pedals of your selection.

In my case, you’ll additionally see a magnet sensor on there – that’s just because I exploit that to lend a hand validate cadence effects coming from the 4iiii Precision (for trying out).  There’s no use/reason why to have a separate magnet sensor at the unit.


With that – we’re achieved and able to set the 0 offset and experience (extra at the 0 offset in a second).

(Observe: The set up pictures I took at the first unit I gained, all different pictures are from the second one technology unit I gained.  There’s 0 distinction between the 2 in relation to set up.  Simply serving to to explain if you happen to see slight variations with appreciate to the opposite energy meters at the motorcycle on the time.)

Common Use Assessment:

When it introduced, the Precision energy meter used to be set to be a dual-leg formulation.  That supposed it might have one sensor on every crank arm, an identical in thought to Verve’s Infocrank, Garmin’s Vector, Pioneer energy meter, and different two-leg succesful formulation.  Alternatively, presently, 4iiii is solely transport a single-leg formulation.  That unmarried leg being the left crank arm, very similar to the Phases energy meter, amongst many others.

Now, I’ll discuss their upcoming twin leg formulation later within the assessment, however for now – that is just a unmarried leg formulation and this assessment is particularly for the one leg crank arm.

However what does that imply from a technical point of view?  Smartly, at its most simple premise they just double your left leg energy.  After all, maximum folks have two legs, either one of which output energy.  So for unmarried left leg programs, they aren’t accounting to your correct leg energy in my view.  Relatively, that will get omitted.

This implies in case your legs have an imbalance (very a lot customary), your general accuracy could be extra variable.  Additional, it’s very customary for other folks to be variably balanced relying on depth or fatigue.  For instance, I have a tendency to be usually balanced as much as about 315w (my FTP), however then past that, I turn into moderately imbalanced.  Within the match that my left leg is weaker, that implies my general energy is being undercut on a Precision formulation.  While if left leg used to be more potent, my general energy could be overstated. I’ll communicate extra about this later within the accuracy segment – however I believe it’s essential to know from the get-go.

After all, all of this left-only stuff is most simply noticed in that there’s just a unmarried pod on a unmarried crank arm, as noticed under:


This pod is successfully non-removable.  Whilst you’ll take away it out of your crank arm, whenever you’ve achieved so that you’ve ‘destroyed’ the pod.  So call to mind it as a long-term factor.  For the ones curious, this might be no other than the Pioneer formulation, Phases or others.  It’s now not designed to switch from crank arm to crank arm.

The pod runs on a unmarried CR2032 battery, which 4iiii recently says will get about 120 hours of battery existence.  That’s up from the place it used to be this spring and summer time, the place customers have been getting a ways lower than that.  Firmware updates since then have advanced issues considerably.  CR2032 batteries are affordable, so despite the fact that you’re getting reasonably much less battery existence, you’ll at all times purchase a pack of 20 them for $7 on Amazon (the ones are the precise ones I exploit).

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The only house I’m now not tremendous delighted with is the battery cap, which I discovered can quite simply bend it’s slot-system.  It’s now not the top of the arena, because it’s simply the cap section I’m pissed off with, and I haven’t noticed any indications it’s inflicting pod leakage problems (ala Phases Gen1 devices).  Nonetheless, I’m hoping they’ll toughen it down the street.


The 4iiii Precision publicizes knowledge on each ANT+ and Bluetooth Good.  Whilst doing this it’ll broadcast your present energy & cadence on ANT+, and your present energy & cadence on Bluetooth Good.  Either one of which use the usual energy meter tool profiles on each protocols.

As well as, 4iiii lately launched a firmware replace which allows Torque Effectiveness & Pedal Smoothness at the Precision formulation.  Alternatively, this firmware replace will solely be freely to be had for patrons of Precision previous to January fifteenth, 2016.  After that, it sounding such as you’d must pay to get such features.  To be truthful, the ones metrics aren’t more than likely super-useful in a single-leg configuration.  However to every their very own.

If pairing by means of ANT+, you’ll be capable to seek and to find the 4iiii Precision formulation by means of any ANT+ succesful energy meter head unit.  It’ll then show the ANT+ ID as a part of that procedure.


You’ll be able to dive in to get additional info equivalent to battery standing.  Relating to Precision, surroundings a crank duration worth isn’t required or applied – so there’s no reason why/wish to achieve this.

At the Bluetooth Good facet, I’ve effectively paired it to a Polar M450, and gained knowledge from that effectively as smartly.


You’ll additionally use Bluetooth Good to replace the firmware at the 4iiii Precision, the usage of the 4iiii app.  This app may be used for different 4iiii merchandise, equivalent to Viiiiva and the unique 4iiiii Heads Up Show.  In our case regardless that, we’re simply going to make use of it to replace/configure our Precision:


While you seek/scan for it and hook up with it, it’ll straight away notify you {that a} firmware replace is to be had.  It’ll then come up with information about it:



The firmware replace takes lower than 60 seconds to finish – so it’s beautiful painless.



You’ll be able to additionally use the app to finish a nil offset:


Talking of which, sooner than you head out, you must carry out a nil offset at the Precision energy meter.  Like many energy meter firms, 4iiii recommends doing this sooner than every experience, from their guide:


This can also be achieved from the app, or out of your head unit.  If the usage of a head unit, you’ll dive into the calibrate choice:


You’ll need to align the crank hands as such, in keeping with the guide.  As soon as it finishes, it’ll supply you two offset numbers, so in case you’re recording the ones, you’ll need to validate you acquire either one of them.  The primary quantity must be between 8,000 and 11,000, and the second one quantity between 18,000 and 21,000.

Within the match your crank arm is out of alignment in keeping with the guide, it’ll notify you that calibration has failed, so simply test the orientation and check out once more.  All beautiful simple and easy.

As soon as out using, the unit will show your present energy and fast energy identical to some other energy meter.  Like maximum energy meters, it’s typically very best to configure one in all your knowledge metrics for a ‘smoothed’ energy meter worth, equivalent to a 3-second (3s) or 10-second (10s) energy worth, because it is helping to cut back probably the most variability this is completely customary for energy meters.


Observe that the 4iiii Precision single-leg formulation will NOT show energy stability, because it’s now not measuring your left/correct legs independently.  Down the street after they permit a complete dual-leg formulation, that might be a characteristic of that two-part formulation.

In spite of everything, I famous previous that I’m on a Gen2 unit.  That isn’t technically their terminology, regardless that, it’s as shut as you’ll get to it.  It signifies that principally there are some minor {hardware} tweaks that happened within the September-October time frame, along side up to date firmware.  That firmware is equal to the ones on Gen1 devices.  The primary distinction used to be that for me, for my ‘pedaling taste’, it it seems that led to accuracy problems on Gen1 problems.  What’s my ‘pedaling taste’?  Smartly, in keeping with 4iiii, their rationalization is as follows (based on a reader remark some time again):

“As a little bit of background, the vast majority of other folks pedal in a usually round movement and obtain correct PRECISION values. For many folks, the crank arm and pedal motive our legs to go back and forth in circles, however a small proportion of cyclists exert strange forces at the pedals. That is what used to be taking place with Ray. Somebody displaying an strange pedaling taste and short of to check energy knowledge with different meters, will receive advantages by way of the firmware improve…

…We perceive Ray’s quirks – such things as Left/Proper imbalance, pronation at the pedal (EG: turning your foot within the bracket), leaning at the within or out of doors of the pedal and a large number of different forces and torques implemented. The Precision energy meter is exclusive in that it understands extra than simply easy bending with an approximate calibration. An actual crank arm can’t be correctly approximated by way of this technique for true torque sensing. Additional refinement to the construct procedure rectified a subject affecting a restricted choice of crank fashions for a small proportion of using kinds. It’s been our very unlucky studying revel in that the crank style despatched to Ray mixed together with his taste used to be in that class. Just one individual of the entire 4iiii’s team of workers has been in a position to give with an identical magnitude of error.”

As for the way 4iiii reconciles this for present house owners, smartly…I’m now not positive fully to be truthful.  I think in case you’re experiencing accuracy problems, they’ll care for you.  However the way you’d know you’re having accuracy problems in case you don’t have every other energy meter (or two) for comparability is for sure moderately difficult.

Energy Meter Accuracy Effects:


For my trying out duration, I used 3 other 4iiii Precision devices (two Gen1 devices, and one Gen2 unit), all of that have been put in on my triathlon motorcycle, a Cervelo P3C.  Regardless that, all my motorcycles are configured quite an identical in relation to trying out/validation devices, usually with 3-4 energy meters in general.


Relating to those assessments, the next configuration used to be used:

A) 4iiii Precision crank-based (left-arm solely)
B) PowerTap G3 wheel hub
C) PowerTap P1 pedals
D) PowerTap C1 chainring unit

For indoor assessments, I’d typically position it onto a teacher that supported rear wheel utilization (usually the CompuTrainer, so I may just stay the PowerTap hub at the motorcycle).

From a knowledge assortment point of view, nearly the entire knowledge used within the research used to be accrued the usage of Garmin Edge 510/520/810/1000 devices, in addition to restricted M450 utilization.  I additionally recorded some knowledge with NPE WASP devices, in addition to different programs.  Information research is in large part achieved in a customized toolset I exploit to ferret out variations, whilst additionally the usage of extra broadly to be had equipment like Golden Cheetah, Excel and Coaching Peaks to validate the consequences.

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Simply to set a baseline, the 4iiii Precision has a claimed accuracy vary of 0w to 4,000w, at +/- 1%.  Additional, it has a claimed cadence vary of 10-170RPM.  Keep in mind that the accuracy vary is of the left-leg, which can also be extra variable in case you evaluate it towards a left/correct formulation because it’s now not taking pictures the best leg energy holistically.

With that, let’s dive into issues.  I’m going to select a couple of random rides that speak to precise stipulations (i.e. temperature adjustments), sprints, strong energy, teacher, and so on…  The purpose being to determine any oddities that I may see.  You’ll be able to obtain the entire experience knowledge used on this assessment on the finish of this segment (plus a number of alternative random knowledge I tossed in there now not proven right here in graphs).

(Observe: You’ll be able to additionally to find a couple of extra knowledge issues in my PowerTap C1 In-Intensity Evaluate, the place the 4iiii Precision formulation used to be integrated in quite a lot of knowledge units as smartly.  Those two critiques display two other units of information.)

First up is a experience from final week, the place I headed over to an area park and did loops there.  As a part of every loop I did a dash up the hill at the loop.

What you spot under is a non-smoothed take a look at that experience.  Common readers know that I at all times display this primary, simply to turn how unnecessary it’s in inspecting knowledge.  This chart if truth be told displays 4 other energy meters plotted at the identical graph.


As an alternative, I want taking a look at smoothed knowledge, which is helping us to simply spot the place issues get misaligned.  On this case, I’ve implemented a 30-second smoothing to the very same chart as above, giving us the under.

In the best hand nook is the important thing to the other colours.  The wattages you spot subsequent to it are simply the one cut-off dates the place my mouse is, it’s now not appearing averages.


So why now not display averages?  Smartly, they are able to be sorta-interesting, but additionally super-deceiving.  An influence meter can also be ‘incorrect’ 100% of the time, but nonetheless if truth be told be proper for a median.  It’s the perfect bar to move.  I’ve demonstrated a large number of instances that straightforward $99 energy answers just like the PowerCal can also be very shut the usage of averages.

However, for the ones curious, right here’s the quite a lot of averages and maximums from that experience:


The issue with taking a look at stats like 1-second energy, is that it will get to the nuances of the way energy meters and head devices communicate to one another.

For a laugh, I’ve picked a bit of the up to now famous chart and zoomed in on it.  I’ve additionally lowered the smoothing to 10s (giving extra variability).  On this case, it’s my first dash of the night time.  You’ll be able to see that each one 4 energy meters observe very carefully each pre-sprint at steady-state (approx. 300w), after which into the dash (approx. 700w).  Typically talking pre/publish dash they have been inside of 10w of one another.  After which throughout the dash, that grew reasonably to a max unfold of 31w.


However there’s a catch – which is that the above chart makes some wrong assumptions.  In particular, it’s now not if truth be told evaluating ‘like to love’.  Relating to Precision, it’s technically wrong to check it to a PowerTap G3 or the P1, or the C1 devices.  Why?  As a result of the ones are all measuring my left/correct leg totals.  While the Precision (like Phases) is solely measuring my left facet.  So within the above case, the Precision measured ‘top’ at my dash height.

What if as an alternative we simply when compared the left-only studying from the PowerTap P1 pedal, to that of the left-only studying of the Precision?  Ask and also you shall obtain:


So what do you spot above?  Smartly, simply the left-leg energy.  We see that the P1 is reasonably upper than the Precision, which is logical (it’s nearer on your leg).  We see the 2 agree on max energy – being inside of 2w of one another (0.6% distinction).  While at decrease wattages, it’s within the 5-8w vary.

I picked every other dash in a while, right here’s the adaptation there.


It’s if truth be told appealing – I believe that is the primary time any person has ever proven evaluating one-leg parts in an influence meter assessment.  Given the motorcycle on the time solely has two left-only succesful devices, it’s not possible to understand which one is in reality proper.  After I upload the WatTeam left/correct succesful formulation to the motorcycle right here in a while, I might be able to slim it down.  However we’re in reality on the level of splitting hairs.

Transferring onto every other experience…

Right here’s the 30s smoothed model of this one.  Rather frankly, issues glance in reality darn beautiful on the 30,000ft degree:


So let’s dive into probably the most height energy, and scale back the smoothing to 5s:


Woah – so on this case Precision for this dash is appearing 50w upper than the others.  So let’s examine. What does the left-only knowledge say about that?


It displays a distinction of about 12w, after which grows reasonably to 21w.  Once more, there’s no approach to know which such a is proper.  It might be the P1 or the Precision (or someplace half-way in between).

Now that is the place we will begin to see probably the most affect of left-only, once I observe a Imply-Max graph, which plots max wattages over quite a lot of timeframes.  You’ll see that up thru about 600w @ 30s, issues align superbly, however after that it seems that that my left leg used to be reasonably more potent throughout the dash – inflicting some upper values as soon as doubled.  To be transparent, this isn’t a unfavourable mark at the technical accuracy of Precision, however simply the truth of doubling left-leg energy.


In spite of everything, a handy guide a rough take a look at cadence on that experience.  You’ll see issues in large part matched fairly smartly.  There’s one blip at the PowerTap G3 round 1/third the best way thru – however that’s estimated cadence, and there’s nuances that may motive the ones blips.  Additionally, don’t overthink slight variations in cadence whilst you prevent/get started pedaling.  That’s in reality an artifact of the best way every energy meter and related head unit handles that split-second the place the pedals prevent shifting.


The above experience is appealing, because it integrated a large number of cobbles sections, as turned around at the map under.  Cobbles could cause cadence ‘problems’ or variances – which we don’t see above.


In spite of everything, one final fast one sooner than we wrap-up.  This one on an indoor teacher (word: I’ve snipped off the top of the exercise the place there used to be some interference in some knowledge units).

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I’ve integrated this one for a laugh, simply to show what occurs once I do left/correct leg drills.  You’ll be able to see there that once I’m pedaling with solely my correct leg, the 4iiii Precision will drop-out fully (as anticipated, since no load goes during the left crank arm).  In the meantime, once I pedal with simply my left leg – it doubles it and displays two times as a lot energy (an artifact of the industry as standard doubling of the left leg).

Past that, the devices all observe somewhat smartly – together with during the 30/30’s, regardless that Precision is a marginally bit decrease.  In having a look on the left-only observe of the P1, positive sufficient it’s additionally decrease, indicating that for no matter reason why that night time my left leg used to be much less tough.  Curiously – this quite fits what I noticed again once I checked out this when Phases first got here out.  In that I’ve noticed slight diversifications between indoor and out of doors rides in relation to stability between my legs.

Finally, I’m now not seeing the rest that’s of outrage with regards to the accuracy of the 4iiii Precision devices at this level, with present firmware/{hardware} – the entirety tracks rather well and with out factor.

(Right here’s a hyperlink to all my 4iiii Precision assessment knowledge, together with all comparative units.)

(Observe: All the charts in those accuracy sections have been created the usage of the DCR Analyzer device.  It lets you evaluate energy meters/running shoes, middle price, cadence, velocity/tempo, GPS tracks and many extra. You’ll be able to use it as smartly, extra main points right here.)

A Temporary Take a look at Precision Twin Sensor Programs:


Again in October I took a take a look at the impending Precision Twin Sensor.  It used to be a easy (and moderately quick) take a look at experience, most commonly to validate it exists, and the way smartly it tracked towards a couple of different energy meters.

You’ll be able to to find main points on that on this publish right here, which talked thru the entirety from the fundamentals to the information at the take a look at experience.

My assessment right here (the only you’re studying) is concentrated solely at the single-leg unit.  As soon as the ‘different half of’ of the formulation, the best leg, begins transport – then I’ll most likely liberate/do a brand new assessment targeted at the complete left/correct formulation.  The expectancy is that this kind of formulation will probably be merely a case of including the drive-side crank setup to the prevailing left-only crank arm.  Thereby making an allowance for simple upgrades.

4iiii has now not launched a time frame for when that’ll happen, thus, I don’t have a dual-leg formulation presently and am due to this fact now not running on a assessment recently for this kind of formulation…as a result of once more, I don’t have it but.

Energy Meter Suggestions:


Observe that whilst it is a energy meter assessment, I have a tendency to not put buying suggestions/comparisons to the remainder of the marketplace in those.  The reason is merely that I’ve created a whole publish devoted to that – with boat a number of details about the entire choices to be had in the marketplace.

Now – what about evaluating between the other left-only choices?  Smartly, at a top degree I’d center of attention on compatibility first.  Get rid of the ones crank hands that gained’t mate together with your motorcycle (or your crank arm spiritual ideals).  All the quite a lot of left-only devices have nuances in relation to compatibilities, in order that’s step one.  The following is taking a look at value.  At the moment, the 4iiii Precision is the least pricey available in the market (easy truth), with Phases carefully in the back of it at a few $129 top class.  In spite of everything, imagine whether or not you intend to improve to a dual-sensor formulation down the street.  If that’s the case, you’d need to slim right down to: 4iiii, Pioneer, Garmin, Polar, bePRO.  All of which give recently transport choices that mean you can ‘improve’ to a dual-left/correct formulation down the street.  However, let’s now not get thus far forward of ourselves, learn the patron’s information publish first.

So seize a cup of your favourite caffeinated beverage and swing on over to that information for greater than you ever sought after to understand.



There are such a large amount of variables and parameters to imagine when opting for an influence meter.  I’ve mentioned all of the ones within the aforementioned purchaser’s information.

That stated, upon getting narrowed down your alternatives, the present 4iiii Precision is a cast left-only choice.  I’m particularly to look how issues glance after they layer within the right-side of the equation subsequent yr.  If they are able to handle the similar degree of accuracy they’ve now, and nonetheless hit the similar value levels as up to now marketed ($749), it’ll be one of the vital less expensive complete left-right succesful choices (with solely WatTeam being less expensive).

Till then, it takes the KOM for the least pricey direct pressure energy meter in the marketplace – and one who’s simply as correct and simple to make use of as ones that value considerably extra.

Discovered this assessment handy?  Or simply wanna save 10%?  Learn on!

Expectantly you discovered this assessment handy.  On the finish of the day, I’m an athlete identical to you searching for essentially the most element conceivable on a brand new acquire – so my assessment is written from the point of view of the way I used the tool.  The critiques usually take numerous hours to position in combination, so it’s a good bit of labor (and exertions of affection).  As you most likely spotted by way of taking a look under, I additionally take time to respond to the entire questions posted within the feedback – and there’s fairly a little bit of element in there as smartly.

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Thank you for studying!  And as at all times, be at liberty to publish feedback or questions within the feedback segment under, I’ll be at liberty to check out and solution them as briefly as conceivable.  And finally, in case you felt this assessment used to be handy – I at all times admire comments within the feedback under.  Thank you!