Shimano has finally done it. They’ve built their first power meter. If you already have Dura-Ace FC-R9100 chain rings and you want a Shimano Dura-Ace power meter to read the strain you’re putting on those rings, this is your only solution. The FC-R9100-P Power Crank Arms.

As this is almost identical to the Dura-Ace FC-R9100 crank arms, the compatibility with bottom brackets and front derailleurs and chains is a given. You’ve already rocked the new arms, these will fit.

The meter can tell you right/left balance, is accurate to +/- 2%, has an integrated rechargeable battery, which is in the spindle for optimal weight distribution. Swapping chain rings is no problem as it won’t affect readings. There’s a switch on the transmitter to zero reset the unit to keep it accurate. The unit sends out both Bluetooth Low Energy and ANT+ signals, so you can choose which way you want to go. The firmware is updated wirelessly as well.

Crank lengths available are:  165, 17.5, 170, 175.2, 175, 177.5, and 180mm