For Shimano sponsored pro cycling teams and training cyclists of all levels that love the precision, power transfer and impressive integration of the Dura-Ace R9100 Crankset, a truly integrated power meter system has been, if not the Holy Grail, perhaps the lost golden empire of El Dorado. With the release of the second generation 11-speed R9100, Shimano finally opened the gates to complete system integration with the dual side measurement system of the R9100-P Power Crankset. The rollout was slow, and Shimano struggled to keep up with demand. As with most other new tech systems, there also a few bugs and phased-in capabilities. With firmware updates the true bugs have been addressed, and in February 2019, a firmware update fully enabled Bluetooth LE (BLE) communication, not just with a smartphone, but also with compatible computer head units and other direct connection 3rd party systems. For the record, the R9100-P communicates via ANT+ and BLE.

In case you haven't heard, Shimano is essentially an engineering company and inside the brain farm in Osaka, it was felt they could best develop and execute their own power meter, given that Pioneer and Stages had managed quite well. The Shimano system is more compact, sleeker, and in many way quite different from the others, reflecting the engineer's perspective on durability, connectivity, and battery systems. Shimano uses a driveside stay-mounted magnet to trigger power and cadence, versus the accelerometers others are using. The battery is also a rechargeable model, that lives in the spindle of the Hollowtech II crankset. Physical wiring connects the non-drive arm to the battery and in effect the right side, which has the transmitting antenna system. Shimano believes the wired system is more reliable and provides the best direct response for information transfer, rather than have two distinct side transmitters for which data is managed in the chosen head unit. The result is the left side crankarm features a slim, lightweight pod that has no known frame clearance issues. The battery has expected charge for 300 hours of use, with a 2.5 hour recharging time, from a direct magnetic connection port on the exterior of the drive side power meter pod, via USB cable. On unit LED indicators keep you informed of the charge as can the Shimano e-Tube Project App.

As stated, the R9100-P can now transmit via both ANT+ and BLE to receiving unit.s Garmin head units like the Edge 1030 that support full Garmin Cycling Dynamics analysis system will show you Left/Right power balance, torque effectiveness, and just about every compatible head unit will show the usual power metrics, cadence, and speed information you'd expect. Shimano uses an Active Temperature Compensation system, keeping the unit accurate despite climate and elevation changes. As with virtually all on bike strain gauge equipped power meters, the unit must be calibrated for Zero Offset at the start of every use period. This can be done with most head units that offer the option, as well as with the e-Tube app, which some people find simpler for this task. The app is available for both iOS and Android, and Shimano has also worked to build greater connectivity for the R9100-P via the app or computer for diagnostic and update information with the Di2 set-up as well. Firmware updates are otherwise easily handled via the app.

The design and construction of the R9100-P within the crankset requires some special installation processes and skills. The R9100 crankset is a Hollowtech II design, but with the left side arm connecting to the driveside and battery via wire, there is a specific insert that is used to establish the bearing preload. With every new R9100-P Crankset you get a special part and a tool for installing it. You have to follow instructions and take great care not to damage the wire, but frankly the process is actually simple and Shimano's instructions are clear. There are also several good installation examples and instruction available online if you are more of a visual learner, especially for the magnet placement and left side arm attachment. Otherwise the crank installation is normal for the Hollowtech II system. As far as connecting the power meter to your head unit, ANT+ ID's is etched clearly on the driveside crank arm and once powered up and spun to activate, the R9100-P will transmit.

There has been some consternation from the cycling public about the wire, rechargeable battery, and general Shimano-ness of the R9100-P. While Shimano does listen and hear this type of feedback, the engineers have their explanations and most of them revolve around typical Shimano requirements of durability, reliability, and highly effective system integration. You aren't still waiting for Shimano carbon cranks, are you? Notice that this is integration within Shimano, not the outside world, which from a tech perspective has moved toward shared standards and common hardware expectations. Shimano rates the accuracy as +/- 2%, a number that is necessary for top-end crank power meters these days, and though some have questioned the accuracy, specifically the left side data, Shimano did address early challenged via firmware update and anecdotally we hear truly positive feedback from users. If you read early media reviews without context of updates, or focus on individual complaints, you likely aren't getting the full picture. Shimano sponsored pro cycling teams sure seem pleased with the R9100-P.

You should certainly do your own research and understand how the power meter will work with your head unit, but we encourage you to look at current media and user information in your power meter selection process. Our experiences have been positive.