Shimano makes power meters for their Ultegra R8100 and DURA-ACE R9200 road cranksets. These are duals-sided power meters with a power sensor attached to the inside of the left and right crank arm. They are accurate to +/- 1.5-2.0%, use ANT+ and Bluetooth SMART and offer 300 hours of ride time using a rechargeable battery.
Additional Shimano Power Meter Info:
Since these are complete power meter cranksets, you must remove your current crankset in order to install the Shimano. If you currently have a Shimano 24 mm bottom bracket on your bike, this is a relatively easy process. However, if you are also changing your bottom bracket in the process, you should expect installation to take additional time. Please note that for these power meters, you will need a Shimano Crankarm Cap Tool for installation (sold by us separately).
Shimano power meters add about 60 grams to the weight of the crankset when compared to a Shimano road crankset without power. This is in the ballpark for other crankset-based power meters.
These power meters measure power from both legs. With a power sensor on both crank arms, they are also able to measure power from each leg individually. This is called independent left/right power.
While 4iiii and Stages make similar, dual-sided power meters on Ultegra and DURA-ACE cranksets, both of those brands use coin-cell batteries. Shimano however, uses an integrated, waterproof, rechargeable battery. In addition, the left and right sensor batteries are connected via an internally routed cable, which means you only have one charging port to connect to.
These power meters use a rechargeable battery and get 300 hours per charge.
Shimano power meters transmit data via both the ANT+ and Bluetooth SMART wireless protocols. This means they are compatible with any bicycle computer, smart phone or tablet. You can also use them with your favorite indoor training app.
The Shimano Ultegra power meter is accurate to within +/- 2.0%, while the Shimano DURA-ACE unit is accurate to within +/- 1.5%. This is on par with most other power meters on the market.
Like most power meters, these use an accelerometer to measure cadence. An accelerometer is an electronic device that is housed inside the power sensor and measures your pedaling rate.
Shimano power meters come with a one-year warranty which covers the product from defects in material and workmanship.