Shimano Dura-Ace FC-R9200-P power meter

The Shimano Dura-Ace R9200-P power meter is the redesign that many of us have been waiting for. Setup is dead simple, the design is compact, and there are smaller improvements such as a replaceable battery door and the fact that it uses the same magnetic charging cable as Di2. There were some accuracy issues with the power readings during testing, but everything appeared to be mostly consistent and the L/R balance is spot on.

Shimano's latest updates of its Dura-Ace and Ultegra groupsets included the launch of new power meters. The Dura-Ace R9200-P is a crank-based power meter that has seen the cranks designed around the power meter rather than the power meter gubbins being retrofitted to the cranks, as was the case with the Dura-Ace R9100-P units. Shimano has done this in an attempt to achieve better accuracy and reliability with the data that the dual-sided design spits out.

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Our testing put the R9200-P up against Garmin's Rally pedals. We've compared the power data, cadence figures and the left/right balance scores of both. 

Comparative testing

Let's tackle accuracy first, as that is the most important factor. I'll begin by saying that the Garmin Rally pedals I'm using for comparison performed well when Anna reviewed a separate set shortly after their launch. The set I have here were consistently reading lower than the R9200-P during my testing and the difference was significant. They were down by about the same margin when I compared to my two 4iiii power meters. 

If we take a closer look at one of the intervals, the average power of the R9200-P is 335W while the Rally pedals measure 307W – 28W (or 8.4%) lower. There's something fishy going on there. 

Rolling home from the same session, I decided to give it a nudge in a sprint. The Rally pedals are ever so slightly faster to pick up the effort, but the R9200-P registered a higher peak power of 942W (I'm not a sprinter). The Rally's 910W peak power is 32W (3.4%) lower.

I handed the R9200-P over to road.cc boss Dave Atkinson for a bit of extra testing. He set it up on his trusty Tacx Neo 2 that has been used to test a number of power meters. Here, the Shimano R9200-P read marginally under the Tacx, giving an average power of 241W for the session compared with 245W from the Tacx (granted, comparing averages across a whole session is of limited value).

The graph shows that the R9200-P tracks the Tacx relatively well at figures between 200-300W and is bang on at around the 150W mark. There is some separation in the figures at higher wattages and this is more noticeable when standing (third interval and sprints at the end). The separation seems to be more apparent the higher that you go, suggesting that the R9200-P is a percentage point or two different to the Tacx Neo 2.

We've never had any accurate crank or pedal-based power meter come in under the Tacx Neo's figures; it's usually the lowest. You put power into the bike through the pedals, with the cranks the next link in the chain, so you'd expect the Shimano R9200-P to read higher than a Tacx Neo because of drivetrain losses (there will always be greater losses the further along the chain you go). This leads us to think that the Shimano R9200-P is under-reporting, but as long as it's consistent under-reporting, that's not necessarily a huge deal.

Left/right balance

The asymmetry of the R9100-P drive-side crank design meant that Shimano and pretty much every third-party power meter maker that used the R9100 crankset had, at some point, a serious headache ensuring that the left/right power balance was accurate. The R9200-P drive-side crank features what looks like a symmetrical design, and the power balance looks to have been sorted.

On every dual-sided power meter I've used, I've been 50.5/49.5% or something around that. For this particular interval session, I was 50.6/49.4%, so nothing unusual there. Dave's test data (above) supported this, showing his usual pedalling imbalance of 52/48%.

Cadence

Often, if you're seeing issues in a set of power figures, you're going to see issues with the cadence data. Shimano still uses a magnet mounted to the frame to deliver cadence data, and it seems to be working nicely.

The R9200-P power meter was quick to pick up changes in my cadence, be that at the start of a sprint, pedalling out of a corner or as I nearly collapsed following an ill-advised fourth hill repeat.

Dave's data supports this, showing that the R9200-P is absolutely spot on. The R9200-P does well at all points, from the general riding cadence between 85-90rpm, to the slogging up a climb speed of around 55rpm, and finally Dave's higher-end leg speed of over 100rpm.

Consistency

I said at the start of the review that consistency in the data that a power meter provides is the important thing for me. Power data is just a set of numbers to work to, and as long as the figures are consistent, day to day, week to week, you'll be able to use the data to measure improvement.

> 12 reasons why you should buy, and use, a power meter

The Shimano R9200-P data has been consistent for me. Okay, it seems to read quite a lot higher than the Garmin Rally pedals and a little lower than the Tacx Neo 2, but quite consistently so, and we can't say for certain which is closest to the true power output. There have been no data dropouts, no weird spikes or troughs on the graphs, and the result is that I'd be happy to train using the data.

The key thing is that if you bought the R9200-P and did your initial testing to set your training zones, you could then train with confidence in the data that is appearing on your head unit.

Setting up

Away from the data that the R9200-P delivers, there is setting up and ease of use to consider. I'm going to assume you've gone ahead and bought a bike with this power meter already installed. With current supply issues, that's pretty much the only way you're going to get one at the moment, so I won't cover the installation procedure that is identical to the last version's and therefore pretty straightforward.

The good thing about this is that while you can hook the power meter up to your phone via the eTube app, you don't have to. Turn on your bike computer – I've got Garmin's Edge 1030 Plus – head to the bit where you search for sensors and after a quick half-turn of the cranks, the unit will show up.

Calibration should, according to the app, be done with the drive-side crank in the six o'clock position, and if everything is rosy you'll get a reading of '5050'. You can also do the zero offset via the small button on the unit itself. It is incredibly simple.

And that's it. You should calibrate your power meter before every ride, but that is standard practice.

Charging

Charging is simple and is done using the same cable that comes with the latest 12-speed Di2 groupsets. That might sound like a small feature, but it is good to have the simplicity of a single cable. Shimano says the power meter will run for over 300 hours and you won't be surprised to learn that I haven't got close to needing to recharge.

Another smaller change is that the cover for the charging port is now replaceable, which is good because it still doesn't feel like the most robust design. Everything inside is claimed to be waterproof, though, so you shouldn't need to worry.

ANT+ and Bluetooth

Shimano has continued with the ability to broadcast power data via ANT+ or BLE, whereas it added BLE power broadcasting to the R9100-P after about a year of the power meter being available.

The daily ride has seen the R9200-P work quietly with no connectivity or data issues; it's a very easy power meter to live with.

Value

First up, I'd like to open a can of worms by debating the need for dual-sided data for the vast majority of riders. Okay, independent L/R data can help to identify an issue before it becomes an injury, but if you normally ride pain-free, chances are that a left-only power meter will give you the data you require at a fraction of the price.

The R9200-P raises the price of the standard R9200 chainset from £549 to £1,199. That's a decent jump, so it might be worth exploring a left-side only add-on from Stages or 4iiii if you haven't got the cash for the R9200-P.

Currently, the third-party brands that install their own power-measuring tech into Shimano's cranksets are yet to release their prices or availability. It'll also be quite a while before we know either, so comparing value is a little tricky right now.

The good news is that the R9200-P has retained the £1,199 price tag of the R9100-P, so there's no nasty price hike with the 12-speed model.

Conclusion

Shimano's Dura-Ace R9200-P power meter appeared to deliver consistent data, but was overreading quite a lot compared to a comparison power meter. The cadence and L/R balance data is perfectly usable for daily training. The unit is very easy to live with thanks to the quick connection to head units, and an improved Shimano eTube app makes updates a doddle. The price has stayed the same as the previous generation.

Verdict

A good power meter with some accuracy issues, but easy to train with and Shimano has sorted the L/R balance issues