This is a question we get frequently and unfortunately the answer is no. Shimano road cranksets (image below) have an integrated spider. Or said differently, the drive-side crank arm and spider portion of the crankset are one solid piece. This means, it would be physically impossible to install a spider-based power meter on these cranksets.
However, for Shimano users, we suggest the power2max ROTOR ALDHU Road Power Meter Crankset.
This is a spider-based power meter that comes on a ROTOR ALDHU crankset. In addition to being a great all-around power meter, here’s why it’s great for Shimano users:
1) If you select one of the 24MM ALDHU Crank sizes, this power meter will come with the same spindle size as your current Shimano crankset and will fit your bottom bracket without any changes. This makes installation a breeze.
2) In addition, if you select the 110 4-Bolt Shimano BCD option, you can also use your current Shimano chainrings on it.