Shimano’s Dura-Ace group is graced by something new. A Shimano-built power meter. The formal name is Dura-Ace FC-R9100-P Power Crankset, but you’ll know it as the Dura-Ace Power Meter. And you’ll also know it as a meter that builds on Shimano’s tradition of only entering into a product category when they know they can do it to the standards they’ve established.
The TL/DR for the crankset is as follows: it’s a power meter that integrates seamlessly with the rest of the Dura-Ace 9100 group. You can just install it, sync it with your Bluetooth Low Energy or ANT+ computer, and go.
It took Shimano years to get to this point, so you should step back for a moment and appreciate what we have here. They started with their regular four-arm Dura-Ace 9100 crankset and enhanced it. The power meter is run off of three strain gauges, one in the left arm, one in the right, and one in the 24mm thru-axle spindle. Provided your computer can read the information, you can get left and right power as well as vector data that can be read by the bikefitting.com machine. It’s pretty sophisticated data, and might take a while to figure out how to best use it.
The left and right side power meters, as well as the spindle strain gauge and the transmitter are wired together. This is to minimize the potential for transmission interference, not necessarily a big deal, until you get power drop-offs when you’re putting in that 20-minute power test you’ve been building towards for the past few weeks.
The transmitter is on the right crank, and it also has a manual zero reset switch built onto it. The rechargeable battery is built into the thru-axle, and there’s a plug on transmitter for charging. The data sent by the meter is accurate to within +/- 2%.
The transmitter sends out both ANT+ and Bluetooth Low Energy (BTLE, BTL) signals. Firmware updates are wireless.
As the meter is built into the crank, you can switch chain rings to any combination without affecting accuracy of the meter.
As the meter has a 24mm Shimano thru-axle, this crankset is compatible with any Shimano road bottom bracket, and will work with just about every frame with an integrated bottom bracket standard (BB30, PF30, BB86, etc) provided you either buy the right bearings or adapters. The inner face of the arms have small boxes protruding, so there might be some limitations on what frames it will fit on, but as of this writing, we don’t know of any. The meter has an internal accelerometer, so you have no need to mount an external magnet, like you find on some systems.
The full crankset comes in 170, 172.5, and 175mm lengths. Chain ring options are 50/34, 52/36, 53/39. If you want 165, 167.5, 177.5, or 180mm cranks, you’ll need to buy them as crankarms and then purchase chain rings separately.
The Shimano Dura-Ace FC-R9100-P Power Crankset allows your Shimano Dura-Ace equipped bike to have both power and be 100% DA