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Shimano R9200P Power Meter In-Depth Review: Astonishingly Inaccurate

I’ve been testing the Shimano latest generation power meter since last summer, comparing it to virtually every other viable power meter and smart trainer on the market today during that time frame. And as one who tests power meters for a living, it’s glaringly clear the Shimano R9200P follows in the footsteps of the previous generation Shimano power meters in one key area: It’s horribly inaccurate.

Mind you, this isn’t just one unit, or just my test unit loaner provided by Shimano. Instead, it’s looking at data from multiple units, sourced from multiple bikes, on multiple continents. Data which is supported by numerous WorldTour Pro cycling teams and other pro riders reaching out after seeing their own data issues. It’s a constant yet frustratingly inconsistent pattern of inaccuracy that I’ll outline in the data section of this review.

However, before we get to that – a quick and unusual preface.

Normally, my reviews are pretty long and detailed – be it for a power meter, smart trainer, or anything else I cover. These reviews usually cover all aspects of the product: From unboxing, to installation, to general use features (like the app, connectivity, etc…)…all sorts of stuff. The point of all that extra stuff being to help people understand all aspects of the product, so even if one portion of the product isn’t to my liking – it might be to their liking, and thus, the review is still useful to them.

However, in the case of a power meter, the *ONLY* thing that matters is accurate data. Or, at the very minimum, consistent data. In this case, it is neither accurate, nor consistently offset (not ideally either, but sometimes workable). The parameters for when and why it’s inaccurate vary within a ride. Thus, all of the typical review components (unboxing/install/app/etc..) simply don’t matter because I can’t see any viable electronic use for this product. And pro teams agree too – they’ve been actively trying to avoid using it for training and racing, but most are bound by Shimano sponsorship agreements. Despite that, we do actually see some top Shimano-sponsored pro teams using alternate power meters on their R9200P-equipped bikes.

Thus for this review, I’m just going to focus on the single thing that matters here: Power accuracy.

With that, let’s dive into it.

Power Accuracy Deep-Dive:

DSC_2263

In this case, the unit I was loaned from Shimano came direct from them, brand new in a box, via their media office. I assume they probably did additional QA/checking on it, as many companies do before sending a product for evaluation. Though I’ve found that, generally speaking, that won’t help much in power meters. The issues I usually find are more algorithm-based than simply one bad unit (in fact, it’s been probably a decade since I’ve had a supplied unit that was physically bad/broken – virtually everything is poor design/algorithms these days if it fails). I’m going to mostly focus on my data, but also splice in some data from other individuals with dual power meters.

From a power meter testing standpoint, you can read a detailed deep-dive on how I do it here. In short though, I do both indoor and outdoor testing, against multiple trusted power meters, in numerous environmental conditions (dry/rain/hot/cold). In this case, I’ve tested it against the following other units over the past 8 months. You can actually find data from the Shimano unit in countless other reviews I’ve written since then.

– Favero Assioma Duo
– Garmin Rally RS-200 Dual
– Garmin Rally RK-200 Dual
– Garmin Vector 3 Dual
– Tacx NEO 2T
– Wahoo POWRLINK ZERO Dual
– Wahoo KICKR V5/2020
– Wahoo KICKR V6/2022
– Zwift Hub

Obviously, with 8 months of testing, I have an absurd amount of data. So instead, in this post, I’m going to try to cover a wide variety of scenarios/data. With that, let’s start indoors, and then transition outdoors. If there’s any takeaway here, it should be that sometimes it’s horrifically inaccurate, sometimes it’s OK. The problem is? You just don’t ever know which ride is going to be good versus bad.

Here’s an indoor trainer ride on Zwift. In this case, it’s compared against the Garmin Rally power meter pedals and the Zwift Hub smart trainer. It’s an ERG workout, with either 60s or 30s intervals. However, there’s one big difference between the first half and the second half – I shifted from the big ring to the little ring:

Set1A-ERG-Split

And as you can see, when I did that, the accuracy of the Shimano R9200P power meter immediately went out the window, offsetting by 20w (the other two units stayed identical/consistent).

Set1A-ERG-SplitCloser

Here’s an even more crispy-clear view that I did on one workout, alternating big ring/small ring each interval. It’s astounding how it instantly goes askew. In this case, I kept the rear cassette in the middle and exactly the same position. You’ll notice the wahoo KICKR V6 & Garmin Rally stay in agreement, despite the Shimano R9200P going off-kilter.

Set2-ERG-MajorDiff

Obviously, this means anytime you’d be climbing in the smaller chainring (such as up a long mountain pass), your wattage is incorrectly overstated by 20w+ (which, is a crapton to be wrong). Here, for fun, I did an entire workout this way, just to demonstrate this. In this ERG workout you can see the 20w offset the entire time!

Set3-ERG-MajorDiffSmallRingZwiftHub

Or again, this time on TrainerRoad and a Wahoo KICKR V6. Mind you, for virtually all structured workouts on virtually all smart trainers, you actually *WANT* to do these in the small chainring to increase the responsiveness of smart trainers (not to go down a rabbit hole sidebar, but basically when in ERG/structured workout mode, lower speeds help smart trainers more quickly stabilize on a set-point. This has nothing to do with accuracy directly, but rather, think of it like riding a bucking horse. A higher flywheel speed makes it harder for the trainer to stabilize. Thus why every training app recommends the small chainring for ERG/structured workouts). Anyways, here’s that TrainerRoad workout – again, an offset:

Set4-ERG-MajorDiffSmallRingKICKRV6

You may be noticing the first few minutes there the KICKR & Rally aren’t quite as close as later, then at the 20-minute marker I do a calibrate there. You should do that anytime you’ve moved pedals around, or if you bring the bike in from a colder spot to a warmer spot (as I did here).

But why limit this data to just mine? Some DCR readers, as well as fellow reviewers, have sent me their data. For example, here’s a DCR reader doing a test on Garmin Vector 3 pedals but also the highly respected power-accuracy-wise Tacx NEO 2T. Here you can see when he uses the small ring, he gets the exact same offset.  In this case, he’s riding Zwift in regular mode (non-ERG, called SIM mode) – meaning this is *PRECISELY* what you’d see outdoors if climbing.

Set5-R-SIM-LittleRingOffset

And then here’s highly respected power meter reviewer Shane Miller, with one of his (many) indoor workouts, showing variance between the Shimano R9200P and the Favero Assioma Duo + Wahoo KICKR V5, repeatedly. This is interesting because it shows yet another quirk of inaccuracy depending on the exact unit – right side dropouts (meaning, the right side of the power meter, so-called drive side). These are visible specifically in sprints, once you zoom in.

Set6-LamaSprintFull

Check out one of these repeating sprints (compared to Favero Assioma Duo’s and Wahoo KICKR V6):

Set6-LamaSpringWide

Notice how the Shimano R9200P drops below the rest? While getting exactly the same max-power on a sprint from multiple units is always tricky (due to transmission/recording timing issues), this gap is huge – about 60w. But the real ‘tell’ here is actually that the Shimano right-side is failing during this sprint. Check-out the breakout here showing left/right power. Here you can see that the Shimano unit undershoots the right side (while the Favero correctly reports it, matching the KICKR’s total power as well);

Set6-LamaSpringZoomed

This repeats itself four times incorrectly on these sets. Except, then for the final and fifth sprint, it magically matches. Why? Who knows. That’s the problem – it’s just not *always wrong* or *always right*, instead, it’s *always inconsistent*.

Set6-LamaSprintFinalGoodSet

About now you may be wondering why different people see different inaccuracies. Shouldn’t they all be the same? Well, not really. In talking with a variety of people in the power meter industry about this, there are a few theories. But talking to one company that actually cut apart one of the Shimano R9200P units and inspected it, they believe the culprit isn’t actually Shimano’s strain gauge placement, or even crank arm casting/design, but rather, the specific other electronics Shimano is using as part of the larger power meter design. In their own testing they’ve also seen many of these fluctuating inaccuracy problems.

For example, here’s a ‘regular’ (SIM mode) Zwift ride; in this ride, there’s very little to complain about. It largely matches the Garmin Rally power meter pedals and Wahoo KICKR V5 smart trainer just fine. The only somewhat minor thing to complain about is it’s oversmoothed, actually matching the KICKR’s slight over-smoothing (due to the flywheel). You see it on some of the surges, where the Rally responds faster (both ups and downs). Not a huge deal, but again – how do you know on which ride it’s happy, and on which ride it’s upset?

Set7-SIMZwift-Fine

So…let’s head outside. I’ve got endless piles of outside data. And like indoors, sometimes it’s fine, and other times it’s wonk. Take this little snippet from a ride in July. What’s going on here? You can see the power drops-out, at the same time the cadence does some weird dropages too:

Set8-OutsideCadenceFails

Remember: In most power meters, cadence is a critical component of determining power. If the cadence briefly stumbles, so will the power. You can’t have power without cadence. However, as I’ll show in a second, this isn’t about connectivity dropping. Instead, it’s about how the unit handles resumption from when you stop pedaling (like you see above/below to the left after a stoplight), as well as how it handles easy-pedaling.

Set8-OutsideCadenceFails2

The above ride was an easier ride with my wife, but still, it demonstrates how it struggles to maintain a consistent story. A month later, in August, there’s this ride, and things here seem just fine for the most part – with very few items to meaningfully complain about:

Set8-OutsideRideWide

The temperature and climate weren’t much different that day, rather my pedaling was. On the July ride, it was an easier intensity with my wife, while the August ride was a bit higher intensity. That, in turn, impacts how the crank arm bends, and from there, how the electronics handle that.

And then this ride in late September seems largely fine too. The pattern? Well, in this case it’s relatively constant intensity (medium), but also all in the big ring. No climbing (only flats where I live), and no major sprints. Oh, actually wait, there was one surge – and during that, the right side spiked out by 100w over, breaking the consistent power that held true the rest of the ride. This is the exact same pattern that Shane Miller saw with the right-said basically failing.

Set9-SprintBreakapart

Here’s a 3hr ride from January on a cold windy day. The windy part likely means nothing. For most of the ride it’s relatively consistent. Then after a few hours of riding, I do some lazy sprints. Maybe not proper sprints, but half-assed efforts. As you can see, the actual sprint data isn’t that different, but, if you look closely, you can see the right side again starting to falter. However, check out what happens in between the sprints when I stop pedaling a few times briefly. The Shimano doesn’t stop producing power despite *CLEARLY SHOWING* I’ve stopped pedaling (RPM goes to zero). This is identical to a typical peloton/group ride scenario where you are frequently coasting for a few seconds to maintain positioning. No wonder the pro teams struggle with this thing.

Set10-CadenceBreaksSet10-CadenceBreaks2

And just to be clear on the above, we know this isn’t a connectivity issue to the Edge 1040, since it’s only tied to when I stop pedaling, and atop that, the other ANT+ accessory at the time (the chest strap) continues recording flawlessly the entire time.

Set10-CadenceBreaksHR

Or there’s this moment on a 3.5hr ride last week, coming from coasting to pseudo-sprint (700w), the Shimano entirely missed it. Like, fart in the wind missed it – off (lower) by 300w at its peak, because of the latency:

Set11-PeakPowerFails

Or, if you prefer, on that same ride where, due to the right-side failures, it undercuts this surge by 150w:

Set11-RightPeakPowerFails

Again, you can pick your poison – which failure do you prefer? Is it the right-side failures, or perhaps the cadence freeze-ups, or maybe it’s the small ring inaccuracies?

And, of course, again, it’s not just me. Here’s some data showing the exact same thing from another unit literally half a world away in Australia with Shane Miller. This set of surges shows how it just entirely misses, over and over again – undercutting the power due to the cadence tracking.

Set12-Lama-CadenceFailures

Normally, at this stage in the accuracy section, I’d try and summarize it all into a tidy paragraph or two. But I’m guessing by now it’s crystal clear. Nonetheless, here’s the distilled version:

– The right side is inaccurate in sprint, undercutting your power significantly
– The smaller chainring data is consistently inaccurate in most situations
– It incorrectly shows power output even after you’ve stopped pedaling
– It undercuts many short surges by 300w+
– It doesn’t handle easy pedaling well (such as in a group ride), giving incorrect data
– The cadence sensor data is often laggy by about 2-3 seconds (despite having a magnet)

I think that’s about it. Frankly, the IQ2 dumpster fire of a power meter project produced a more accurate first gen pre-production prototype three years ago, than Shimano has made on their next-gen version of their power meter, even after Shimano acquired Pioneer (who actually made quite good power meters). It’s absolutely mind-boggling that most of these weren’t caught in testing. Or, they were caught, and Shimano just didn’t care. Cross-chaining issues like small-ring data being incorrect was a problem 10-15 years ago in power meters. Every power meter company in the world knows to test for it, and it’s a trivial test to do. There’s no excuse for not getting that right in a modern power meter.

(Note: All of the charts in these accuracy sections were created using the DCR Analyzer tool.  It allows you to compare power meters/trainers, heart rate, cadence, speed/pace, GPS tracks, and plenty more. You can use it as well for your own gadget comparisons, more details here.)

Wrap-Up:

DSC_5437

As if this post somehow needed a wrap-up, I’ll give it a whirl.

For the second edition in a row, the Shimano power meter simply isn’t accurate. Not even close. And it’s been ‘not accurate’ for a long time. The previous model wasn’t accurate, and then Shimano made a big deal of implying this one would be accurate. Shimano stalled for many months to get review units out to any reputable reviewer, and I finally got one last summer. I’ve put a lot of rides in a lot of conditions on it, and ultimately, the answer is unequivocally clear: It’s simply bad.

And mind you – that’s the same overall result that another industry-trusted power meter reviewer found, as well as numerous other media outlets. And now you can see why I skipped going through the motions of spending hours consolidating photos of installation, general usage, screenshots of the app, or anything else. With a power meter – if it’s not accurate, then nothing else matters. Period.

Unfortunately, for many bike consumers and pros alike, you’re stuck with this unit. I’ve been looking at new bikes recently, specifically triathlon bikes, and many of them are equipped with the Shimano R9200P as a non-removable configuration. Thus, you’re paying an extra $1,000 (typically) for the privilege of something that’s not accurate or consistent. And lest you think you’re alone here, WorldTour Pro teams and their riders are suffering this same problem, except in their case Shimano has paid their team vast sums of money to ride the R9200P. And while these teams are riding the R9200P in racing, a number of them are deferring to other power meters in training. And even last year we saw Lotto-Soudal as a sponsored Shimano team also ride with 4iiii power meters as their power meter sponsor.

Complicating matters further is that many media outlets also have extremely heavy advertising spend from Shimano, which is one reason why you don’t quite see as many detailed accuracy-focused reviews of the Shimano power meters. But again, if a power meter is inaccurate, it serves no purpose as a product.

And while some might ask about the Shimano Ultegra R8100P, I haven’t tested that unit. Though it’s based on the exact same electronics design as this one, and there’s no reason to think (and no data to support) it being any more accurate. I don’t, at this point, have plans to test that unit. Instead, I’m already working on testing other Shimano-compatible options. For example, the Stages LR (dual-sided) version for the Shimano R9200 DuraAce crankset is on the bike and the first rides completed. That unit tested extremely well by GPLAMA/Shane Miller, and my initial data is looking good too. 4iiii also has a variant as well for the R9200.

Stay tuned for more testing to come. With that, thanks for reading!

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106 Comments

  1. Koen Miseur

    I’ve heared that this is the main reason (second reason would be money of course) that Jumbo went with SRAM this year, they weren’t allowed to use another powermeter.

    • Chillfmm

      In pro racing you either keep up at the front or you get dropped no matter what wattage your powermeter tells you’re producing.

      Jumbo went with SRAM because they paid them more. They might get better powermeters but they get worse shifting (slower & less powerful). It’s not a win-win change.

      It’s unacceptable, however, that such an expensive piece of kit is neither consistent nor accurate. And it’s the second iteration…

    • “In pro racing you either keep up at the front or you get dropped no matter what wattage your powermeter tells you’re producing.”

      Sorta. In a non-TT stage, that’s mostly true. But the power data from that day is still deeply poured over by teams. It dictates whether or not a rider goes to other races (or which event they go to), whether they get rest, or even attacks/plans for the next day.

      In grand tours or others with TT stages, it’s a core part of how most riders pace that stage. You’ll often see it written it on their handlebars their power levels.

    • Koen Miseur

      So much wrong about this!

      “In pro racing you either keep up at the front or you get dropped no matter what wattage your powermeter tells you’re producing.”
      No you don’t look, at Remco, he rides his own power and no one else’s. He knows how much power he can ride at, if he needs to go over the other riders are A) better or B) will fall back or C) he will not loose a lot of time. Heck Sky did this so long, they know what they could do and that it was very close to the max. How many times you have seen people going to fast and getting back without even a acceleration, that’s because they went over their max power. How dumb would it be to follow such a rider, so yes in such a case a powermeter helps 100%

      “(slower & less powerful)” yeah show me data that supports this, every high-end groupset made in the last 5 years is powerfull and fast enough!

    • Jimbo

      You know what they will receive in pay, how??

      BTW, I disagree with you entirely on the “get worse shifting”. That may be your feeling but it does not agree with my experience.

    • Andy

      In my experience Ultegra 6800 on my TT bike is light years ahead or Force AXS.

      Ironically the thing that did make my AXS bike better – a Shimano 12 speed casette!

    • CHRIS ROBERT

      A shimano cassette will improve any SRAM shifting system 8speed – 12 sp.

    • JanC

      The data is also used for planning recovery, food intake, etc.

    • Paul

      Pored over, not poured over. Sorry, I know I’m being a dick, but I have to do this.

  2. Daniel

    And with one fell swoop of his pen the shimano power meter was dead.

    • Andy

      Except as Ray alludes to it’s not, we’ll just flogged these to justify an extra grand on your next bike purchase, you’ll pull the battery out and pretend it doesn’t exist and bolt on your preferred power pedals anyway!

      It’s really just the consumer that’ll lose out on this.

  3. Pavel Vishniakov

    Hi Ray,

    thanks for the review!

    It’s mind-boggling that after all the years of criticism and Pioneer acquisition Shimano still delivers a bad powermeter.

    On a side note: since you mentioned IQ2 – is it legitimately dead or does it just smell bad?

    • They’ve somehow revived themselves, supposedly. Some aspect of production is flowing again, but the definition of ‘production’ is fuzzy at best right now. Small numbers of units are shipping in recent weeks, but they keep redefining whether or not these units are final-final, or just sorta-final. Either way, they’re going to paying users.

      I’ve been watching/keeping track. I’ll buy a unit once they’re final-final (sounds like maybe a March production run)? But till then, I’ll watch the situation from the sidelines.

  4. Daniel

    Missed opportunity on “if it’s not accurate, then nothing else matters” 😉
    link to youtube.com

  5. Warren Beck

    This is bad news. Especially because it raises the cost of the Di2 groupset by a lot.

    Given that LR power data has not been demonstrated to be really useful except maybe for monitoring injury recovery, the consumer is being asked to pay for a complicated system that is inessential for training and racing. I am happy with my spider power meter and its guesstimated LR data.

    It will be really interesting to see what the Stages LR DuraAce power meter does.

  6. David E.

    So, why doesn’t Shimano plunk down some cash and buy a distressed Wahoo? That would give them trainers in their product line-up, and it would give them a company that seems to have figured out how to measure power accurately. (I know they already bought Pioneer with probably the same idea in mind, but well, that clearly didn’t work.)

    • I think they have the expertise and knowledge to do this. I just think they’ve made a specific business decision not to try.

    • MatthewQC

      Entertaining this notion (I have no idea whether it’s realistic) … boy would I love to be a fly on the wall while they decide what to do with Speedplay after said acquisition. You know Shimano isn’t going to keep it around when they have SPD, and you also know that it doesn’t sell for very much after Wahoo basically stripped them of anything of value save for the Zero pedal and the Zero power meter, which has internals that won’t fix the crank-based power inaccuracy and is also incompatible with the SPD spindle.

  7. Dave

    Well it’s better than Limits 🤦🏻‍♂️

  8. Stan

    Thank you for saving me from wasting my money on a shimano PM, love their group set…but will stay away from their PM crankset.

  9. Mark Shaffer

    Interesting. I bought a second-hand bike which has the R9100P previous version (I didn’t buy the bike for the power meter!) and tested against my Assioma pedals. For my first test, I saw inaccuracies but had used my Coros watch and wondered if that was fair, so for my second test, used a spare Wahoo head unit. All looked good in that the average power was really close. I was in the big ring for the whole ride. I can see that the L/R is definitely off.

    A shame as I was hoping not to have to switch pedals quite so often. The Assiomas have been great, so they’ll be
    back on the “new” bike.

    link to analyze.dcrainmaker.com

  10. Bartlomiej Siedlecki

    Excellent review Ray! I wonder if there’s really a power meter issue or are the cranks already deflecting and beginning to crack 😉

  11. Alex

    By now it’s obvious that Shimano doesn’t have the know-how to make a high quality power meter. Even after acquiring Pioneer.

    It’s sad they keep pouring resources into a crappy product that consumers pay a lot of money for (sometimes involuntarily) instead of deciding they’re not going to get it done. Would anything prevent them from buying 4iiii or Stages?

  12. Maxwell

    I have a question. it is possible to let the reader know which color is which unit in the body of the review? The lettering on the pics is small (often blurry( even on my larger monitor and it would be helpful to have a note saying the Shimano was green, for example.

    If not, that’s okay too. I tend to skip over the graphs because they are too difficult to read (and I know you post a link to the workout as well)

    • Good call. Also, a good reminder that I want to make that overlay box a big bigger.

      For this review (and the first time ever), I actually set the Shimano unit to GREEN for every single data chart. 🙂

    • Moritz

      Sorta off topic, but Ray what are your thoughts on the best MTB power meter? Ideally I’d like it to be a pedal based SPD model which leaves the Rally XC, SRM Power X, and assiomas which require a DIY conversion. I’m pretty biased against Garmin these days, as I have had to pop many frustrating experiences with their head units and the Vector 2 pedals. Really what I’m looking at is which of these would likely be the most durable for MTB and also be readily changed to my Gravel bike.

    • Yeah, the options are semi-limited (if you want it to be pedal based).

      SRM X-Power: Certainly, I found the X Power to be good accuracy-wise, but battery wise it was challenging. The newer hardware since my review is supposed to have taken care of that, but I’ve not tested that.

      Assioma DIY Mod: Obviously that’s an option, but maybe not everyone’s cup of tea. Favero has long…long…long teased doing their own SPD unit, but who knows when that might happen.

      Garmin Rally: I think there’s a reality there that your old Vector 2 unit is nearly a decade old (8 years this spring), and for better or worse, Garmin learned a heck of a lot since then. While Vector 3 has its battery issues, they eventually solved that, and we haven’t seen any meaningful issues with Rally (including the SPD side), and you figure we’re 2 years on now, so by now we’d have seen things pop-up. People have beaten the crap out of them (including me), without much noise.

  13. Phil

    I know this isnt exactly on topic but you also noted some powermeter issues with the rival quarq axs and said you were waiting for a response from sram and was wondering if you ever heard back from them on a fix. Thanks!

  14. Jojo

    So you say Mathieu van der Poels powerdata are much to high. Maybe he doesnt know it, and trains all year wrong 😀
    Oh man he could be such a big talent, wasting some Shimano years

  15. John Rankin

    Hopefully third-party options such as Stages will be accurate for those of us who do not want to use power meter pedals.

    • jim

      Not that it is, or has been, everyone’s results but my Stages units (both Gen 3) turn out complete crap readings. I am not impressed.

    • Michal

      On old cranks? Yes. On newest Shimano cranks (R9200 etc.) it’s good. It’s likely the first Shimano dual crankarm based power meter that works like it should. Check Shane Miller’s review of R9200 Stages dual sided power meter.

  16. davie

    Shimano went to direct mount spider/chainrings for 9100 XTR yet kept the weird integrated crank/spider for Dura Ace R9200. Now they reap the rewards for their decision. What an amazing own-goal.
    I guess the addiction to proprietary parts is more important than accurate power meters.
    For me, I will keep my rotor cranks with 24mm steel axle and power2max ngeco spider/powermeter. This combination provides accurate power and is compatible with all 11 speed and 12 speed shimano road chainrings.

    • Michal

      Exactly this. Anti-consumer practices bite them straight in the ass. They couldn’t allow for exchangeable spider, because it would enable cheap third-party spider baser power meters. And here we are… Good thing they didn’t use integrated pedals as well to fight Favero.

  17. John B

    C’mon Ray. Tell how you really feel.

  18. Adam

    “Shimano’s cycling sales hit record high despite slowing demand.” (reported by road.cc)

    Slowing demand… now even slower!

  19. Robert Chung

    So, a couple of comments.

    1. These kinds of deep dives into finding a pattern to errors is hard to do, and not many people do them. Ray is one of the few.

    2. Oddly, lots of people think that accuracy doesn’t matter, only consistency does. It turns out that the errors here are pretty consistent: small ring biased high, sprints biased low, laggy response.

    3. Over the course of a long ride, you don’t spend much time sprinting, and you may not spend much time in the small ring. That means that over the course of a long ride, your *average* power may not look very different than from a different power meter. The moral of this story is that reasonable agreement on average power is a very low bar to meet, yet this is what people cite all the time. What’s important isn’t how close two power meters are on average, what’s important is knowing when they’re not.

    4. A lot of people with power meters say that consistency is important but they don’t ever check for it, or even know how. The problem here is easier to discuss because Ray (and others around the globe) spent a lot of time and effort to track it down but if it were that obvious Ray wouldn’t have needed to do it — it would’ve been clear. So people thinking they’re safe cuz they didn’t buy this? Dream on.

  20. Scott R

    If anybody is interested; I just replaced my main 5 year old Quarq DZero PM after it appeared to wear out with increasing poor readings(not blaming it, it worked so well for so long) I do mainly indoor Zwift rides on a Tacx Neo. So i went with a Shimano Ultegra PM. Ive always felt the Neo was low by about 3-4% compared to the two Quarqs ive had and also two old school Powter tap hubs as a reference off trainer on road compared to the cranks. I had some Stages LR Shimano and can say they were crap consistency and accuracy wise. So switching to Shimano has been interesting. Accuracy wise on an average Zwift ride the Shimanos are 3-4% up on the Neo, consistently. There are some quirks ive found to them; they respond well to a 2-3min warm up before zero offsetting/calibrating, as this seems to “wake” and settle the left and right arms even though they are tethered for better accuracy. Then they just work ok and im happy with them. There could well some spikes or drop outs I just can’t see but overall I don’t notice them with Zwift or the recording Garmin. I use a second head unit to read the Neo at all times as a reference point. Im very happy with the Shimano. PS I dont work for them!

  21. Don Rhummy

    Ray, how is this possible?
    I’m not asking how it’s possible that company that makes the best electronic shifting can’t figure out power meters. (They’re obviously different) I’m asking how can a company as established as Shimano allow such a subpar product to go to production?

    • chris g.

      I hate to say this however, it’s how Shimano does business …they have a record of products with serious issues that they won’t “fix”

      Their cranks fail over and over in humid environments.
      They had a bad cassette design that failed and they wouldn’t replace it unless it failed.
      This power meter.. It has had bad reviews/issues since it was released.

      C

  22. jgpallero

    I can’t understand how Pioneer has one of the best power meter in the market installed in Shimano cranks and, after Shimano purchased Pioneer, Shimano power meter is still crap…

  23. Martin

    Nothing makes me trust someone more than an honest evidence-based bashing of a product. Right on!
    Eternal 4-star reviews help nobody.

  24. Paul

    Blimey, with the power I usually put out, this meter would be around 50% accurate! 😂

  25. Andrew Newsom

    Is it worse than the Gen 1? Wow

  26. vicent

    do you think this is something that can be fixed with a firmware update?

  27. Jeffrey Watts

    Is it safe to assume that other shimano based power meters, such as Pioneer/Stages/Giant have the same/similar issue?

    • Dirk

      No. I‘ve a 4iiii left side only PM mounted on a DuraAce crank set. It‘s very accurate. When I fully power out I get the about same NP like on my MTB with Quarq.
      So for me a option would be to go with a normal DA crank and 4iiii PM. One-sided power suits me fine.

    • James

      Jeffrey, stages uses a different mechanism for reading power, so their meters should be good. Ray mentions that in the article although he hasn’t tested it yet. Can’t speak for Giant or Pioneer, although both have good reputations (so does Shimano though?…)

  28. John Grotland

    Watching the UAE Tour stage 2 and noticed that Deceunick has the R9200P cranks and Garmin Rally pedals. Good guess the head units are connected to the pedals and not the cranks.

  29. Mike Comer

    Any insight if Quarq will make a 9200 version of the QUARQ DFOUR DUB POWER METER? I have the Shimano Power meter and it is wildly inaccurate reading almost 20 watts low compared to my three Quarq Power meters on different bikes. The L/R is also very inaccurate. Weighing my options as to what to do here……

    • Mac

      I have the R9100 version of the DFour Dub with R8100 chainrings on a 12speed Ultegra. It works fine and IMO while the lines between the spider and the chainring doesn’t matchup exactly it looks fine too. The four arms are still line up, albeit of a slightly different profile.

  30. Dirk

    Thanks four your report, very solid work, Ray!

    For me this is a litte disaster, since I am heavily waiting for the possibility to order an CUBE LITENING AIR C:68X SLT. They are still not available, I think mainly because of delivery problems due to Shimano. After ready your posting, Ray, I would really do without the Shimano PM, just adding a 4iiii left side PM later (one-sided measurement suits me fine). Hope the CUBE installs such an option after reading your test. I mean, who will every buy such a PM on aftermarket? So with that PM pre-installed, the bike is dead for me.

  31. Witek

    Any chance of a recall? I bought the 8100P cranks hoping Shimano figured it out but my PM has been both inconsistent and inaccurate (same as 9200P). I would love to keep with Shimano due to the excellent shifting but a PM this bad is useless for its designed purpose.

  32. Patrick Cope

    As ever, amazing; balanced review(s) – so huge thank you.

  33. Patrick Cope

    Lol, that’ll be me being special then! Finally, after 16months of waiting got my Merida Team Scultara (yay!), with you guessed it …..’the meter of inconsistency”. Anybody gone through the process of how you prove to Shimano it isn’t within 1.5% accuracy and therefore faulty (returned under consumer goods act etc) – obviously ‘I’ can follow same process as DCR, but more interested in the ‘Shimano’ process, which obviously isn’t as in-depth as DCRs otherwise “they’d” know it’s garbage…..and they’d never have released something that bad – surely????? 🙂

  34. BarryR

    Those cadence graphs show all the signs of using heavy averaging to try to fix spikey data, possibly even to fix cadence dropouts. Ask any power meter algorithm developer – if you end up applying averaging then you’re already losing. Averaging is usually used when the underlying data has serious problems and/or knowledge of digital filters is lacking.

  35. Bradley Tipp

    I went with Stages for the left side with my 9200 and recently added the right side using their installation service. So far all seems good with no weirdness. I also waited for Shane’s review before pulling the switch.

    • Clive E

      Thanks for this article Ray.
      As a new owner of the Ultegra P8100 crank this is a little worrying. I wonder if firmware would be able to address the issues?
      I’m not seeing too much of a deviation of my power output vs stages and my left vs right pedal is showing 46/54 which is pretty usual for me…..but I’ll be interested to see how this all plays out.

  36. Brian

    Thanks for the review. I have this 9200 power meter.

    The other day I happened to check it against my kickr and the 9200 power meter was consistently lower by ~10w, whereas my older quarq never had this issue.

    I’m a recreational rider and the bike it’s on is no longer going to be primary bike in a few months so I’m not fussed about it, but it’s egregious. I feel bad for people that bought it and actually need to pore over the data. Too bad because it’s a good looking crankset.

  37. Thomas

    My 2015 single sided Pioneer Power Meter is still vastly superior!

  38. Nik

    Hi DC!!!
    It’s the same also with Giant power Pro powermeter? I suppose
    that also this one come to the Shimano production…

  39. Andrew

    So Ray, any chance that the Ultegra unit is accurate or a we waiting 4 more years for the next iteration of Shimano’s power meters?
    Sounds like they needed to get some of the Pioneer personnel as much as the tech acquisition.

  40. A Watopian

    Low EQ Comment: Astonishingly Inaccurate
    High EQ Comment: Legendary Equipment for Online Cycling!

  41. Dries Oomen

    Interesting testing, Ray! I am wondering, is it possible to use a power meter on a Gates CDX equipped belt drive bike? Presumably using a power meter, but would it be accurate when it’s designed for chain use? Would really like to hear your thoughts on that and even a model you would recommend in that situation.

    • Dries Oomen

      I meant to say ‘presumably using a crank power meter’

    • Niels Van den Put

      Crankbased powermeters measure the force put on the cranks, it’s irrelevant if that force is then transferred through a chain or a belt to the rear wheel.

      Looking at the Gates cranksets, most of them use square taper bottom brackets. It should be possible to mount a powermeter on a crank for that type, but I’m not really aware of any available or “factory install” (where you send in your own) powermeter cranks for that spindle. I imagine the market for them is tiny, no modern race bike has a square taper bottom bracket.

      Another option would be spider based powermeters, but again, I’m not really aware of square taper compatible spider based powermeters. I see one Gates crank for the MegaExo bottom bracket but that’s direct mount and also no compatible spider based powermeter for that spindle.

      The most feasible option is powermeter pedals (single-sided or dual), which does require you to go clipless. The budget option is a Velocomp Powerpod (but I had a crap experience with an earlier model, power was way inflated when riding downwind, which I think is an inherent problem with the technology).

  42. I sincerely wish I had the disposable money to just buy and tear open meters to mount them up in my cal rig I built for a customer recently (which is for targeting 0.1% error devices 😉 and wire into them with my electronics to check for flaws. Just not worth the cash for youtube videos.

    However if it’s electronics (or how they connect to strain gauges), ugh…. that’s…. cost cutting at it’s finest. I’ve seen several cost cutting measures by multiple companies now — race to the bottom and consumers lose. Either you know you’ve compromised the design or you don’t have the right people at this point. There is no excuse for the big guys.

    • Eli

      So they shouldn’t cut costs to $6? :-p link to sensitivus.com
      Feels like power meters haven’t improved much in awhile. Strain sensors, sure I can see how they haven’t changed but the cpu/microcontroller side of the power meter? Don’t they have more compute power or lower power draw for the same compute power? So either longer battery life or can do more

    • They haven’t improved – few brands maintain, others got worse. Some newer ADC’s are better for similar price so maybe some cost savings there. Some clever engineers did some powersaving.

      The 9000 generation went asymmetric and most companies just “faked” the fix. The dual with assymetric integrated spiders saw few with a fix, but nobody had a fix by 9100. 9200 walked back the aesthetics and should have helped but I guess big S went cheap on electronics?

      Sadly, the knock on effect of flagship semiconductor processes slowing down (now with branding!) has basically stopped micro’s from moving to the smaller nodes and ANT+ development getting even more niche means most people are sticking to the nrf52832/840/810/810. So 6-7 year old chip is our go to still.

      6 dollar pcb as yougathered is meaningless even if it hadn’t cut corners – cost to install a strain gage, cure it properly, install the plastic housing, test waterproofing, calibrate it, then package is actually the main the cost when you include all that labour is the main cost of a powermeter and that doesn’t change or actually goes up with inflation.

      But that USB connector…. under the antenna keep (metal) out zone. \(〇_o)/

    • Eli

      I thought nRF53 replaces nRF52? link to thisisant.com
      Is no one using it for that purpose?

      Seems like having a stiff crank conflicts with having good power data. The place where you would want to place the stain sensor is also the place you’d want to build up more to prevent flex. Also send like you’d want the electronics closer to the bb as there is more space to work there (being closer to the crank means you might interfere with where the frame is) and you’d want the crank to flex less closer to the bb. Not to mention how you wouldn’t want flex from supporting the rings to be picked up when measuring flex of the arm

  43. Vic

    Was any testing done using Shimano Dura Ace brand pedals on their PM crank? Or only with third-party brand?
    It is a system you know 😉

    • Shimano does not make power meter pedals. I used power meter pedals as part of my comparison data. Some of these were Shimano-partner pedals via Garmin Rally RS-200 (which is the Shimano variant of that pedal, approved by Shimano).

      Either way, there’s no power meter in the world that cares what pedals you put on it, aside from simply doing the zero offset (which I did every ride), to account for the empty weight. Not even Shimano themselves would try and say the ‘system’ required Shimano DuraAce brand pedals to be functional. Mostly because they’d only be digging their hole even deeper if they attempted that line of thinking.

  44. Bradley Tipp

    Ant plans to test the Stages L/R system. I know Shane is happy with it, but you do such an Indepth job I would still appreciate your analysis.

    • Yup, already started! I’m travelling this past week, but will resume testing next week. So far seems promising.

    • Bradley Tipp

      Cheers Ray.

    • Felipe Serra

      The long term problem that i have with stages L/R is the waterproofness of the drive side…

      If water pass through battery door, you have a problem…

    • BIll

      I use them for 4 months now and problems began. Power dropped suddenly twice and need 3 calibration attempts to come back to normal. Also right crank calibration is in range 940-945. Balance is also off. Working with Stages support and they want right crank back to them. I am thinking going back to Assioma..

  45. Luciano

    Any reaction from Shimano? Did they at least try to get in touch to explain and give some visibility on how they plan to mitigate the issue?
    I have the R9200P with my Canyon Ultimate and since I read your review brought back my Assioma Favero pedals… A 1300 euros useless device…
    Anyone else has contacted Shimano?
    I am planning to do my own dual recording and contact Shimano for an explanation / compensation…

  46. Tute Zaek

    Did the old Pioneer units had these kind of problems?

    • Bradley Tipp

      My Pioneer based R9100 dual never had any issues with balance or weird behavior. I’m not sure that is true for all Pioneer R9100 units though.

  47. Actually it is pretty crazy for such an industry giant.

    I would love to know what happened to all the great Pioneer research, product knowledge and IP that Shimano purchased. 🙂

  48. Peter

    I’m assuming there has been no change in the Shimano power meter since its release. I have a new 2024 model bike on order that will be coming with R9200P fitted. My plan is to remove the cranks and sell if possible and replace with a Stages LR unit. An expensive exercise but a necessary move if I want reliable power on the new bike. My other options were pedal based power meters, but unless I swap the crank out for a non-power version, I will be carrying around a power meter I won’t be using and again an expensive exercise when the Shimano power meter should actually work!
    So my question is, has Shimano made any improvement to this since release or still the same spec?

    • Harv

      I’m in the same boat – a new bike coming with this power meter already installed. So Shimano it’s not offering any refunds??? I have good power meter pedals which I suppose I can use – does the Shimano power meter actually add any weight to what is otherwise apparently a very good crankset?

  49. Gary

    Looking at a new bike and get Ultegra DI2, a first for me. The builder offers 4iii single sided of the Shimano double sided. £400 extra for the double sided. Got the 4iii on the current bike, does enough I think, but is it worth getting a double sided, for a lot less than adding later. This review suggests now, but any firmware updates improved the readings? Interested in views on this one

  50. Moshik

    Hi

    It’s about 6 months from the review has anything changed?
    I have a friend who is a bike shop owner and he rides with the Ultegra and says that the Ultegra power meter is great. Do you have any knowledge about the Ultegra?

    Thanks
    Moshik

  51. Harv

    I have a new bike coming with this power meter already installed. So Shimano is not offering any refunds???

    I have good power meter pedals which I suppose I can use – does the Shimano power meter actually add any weight to what is otherwise apparently a very good crankset?

  52. Flavio Giovannini

    Great Job DC

  53. Flavio Giovannini

    Hi Ray, just read that Yesterday, Shimano, has released a firmware update that fixes the accuracy issue of the PM.
    Do you already know if it is believable? I’d like to buy a new bycicle and durace would be my choice, unfortunately the PM is included.

  54. Matthew Holecko

    Would love to see your take new firmware update and pairing with your Di2 system for increased accuracy and how it impacts things versus your initial review.

    • Yup, I’m aiming to get it mounted up to a bike and updated firmware on Monday, and then do the initial alternating interval test seen above (where I switch rings/gearing multiple times), to see how it handles. If it handles that well, then I’ll expand testing to other areas.

      I think the solution is a shim at best, but, as I’ve always said – I don’t really care how a company achieves accuracy (be it GPS, optical HR, power, etc…), as long as they do. The challenge with a solution like this, is that I suspect it’s very susceptible to edge cases breaking it. Figuring out what those edge cases are, and how edge they really are, is key.

    • Andy

      Great, can’t waite to get your update!

    • Update: Firmware update failed, as in, it won’t install. Working with Shimano people to untangle, but looks like they’re just going to send over a replacement unit.

    • Richard Rauschenbach

      I was able to get the Firmware installed, but it took multiple attempts/reinstalls. Not an easy or clear process. Included having to resync derailleur to powermeter several times. It initial appears to be giving me more accurate numbers on the small ring, but I’ve only ridden a few times. Wish they would fix the power readings when I’m not pedaling. Seems to take anywhere from 10-15 secs before it shows zero power. Looking forward to seeing what you get.

    • Philipp

      Any news? 🙂 Thx in advance.

    • Nothing from me. No replacement unit yet from Shimano. :-/

    • Daz

      Any luck on getting the firmware update and testing if it helped?

    • Nuttin.

      Granted, after GPLama/Shane Miller showed it wasn’t awesome, they probably realized I was going to find the same. :-/

  55. TexasNightRider

    I’ve been using the 4iiii dual PM for the last year with no issues. Have a new (additional) bike being delivered in January 2024, and I’ve decided to wait on 4iiii to make available a dual PM for the Ultegra 8100 50/34 crankset. 4iiii replied to my inquiry today that an updated PM for that crankset is in development and should be available in early 2024. Great PM review by DCRainmaker.

  56. Fisherski

    What do you do with a Shimano Dura Ace power meter that came with the bike? As they advertise +/-2% accuracy and it is far away from that shouldn’t they have to reimburse you for a false claim? This is a little ridiculous that it is so wrong and yet they keep on selling it without any responsibility.