You have a couple of great gravel power meter options for Shimano GRX 810 and Shimano GRX 600 cranksets:
Left Crank Arm Power Meter
Both 4iiii and Stages make a Shimano GRX RX810 power meter which is compatible with all Shimano GRX cranksets including GRX RX600. With this type of power meter, you swap out your current left crank arm for the new power-equipped version. These power meters are affordable and easy to install. The trade-off is they only measure left leg power.
Please note, these power meters do not come in a GRX 600 version. This is because, the backside of the GRX 600 crank arm is not flat, rather it has ridges, and therefore a sensor can’t be attached to it. However, these GRX 810 power meters can be used on a GRX 600 crankset without issue.
4iiii PRECISION Shimano GRX RX810 Power Meter
4iiii PRECISION Shimano GRX RX810 Power Meter
Stages Shimano GRX RX810 Power Meter
Stages Shimano GRX RX810 Power Meter
Please note, these power meters attach a sensor to the inside of the left crank arm. On some bikes, there is not enough room between the left crank arm and the chainstay for the sensor to clear the frame. Therefore, you should make sure you have at least 10 mm of clearance for Stages and 4iiii PRECISION 2 power meters and 8 mm of clearance for 4iiii PRECISION 3 power meters. Also, please make sure that you don’t have a bottom bracket mounted rear brake (used on some aero and TT bikes). Please refer to the image below.
Pros: Affordable, easy to install, don’t have to change crankset
Cons: Measures left leg power only
Crankset Power Meter (Spider Based)
power2max NGeco ROTOR ALDHU 24MM Power Meter for GRX Chainrings
This power2max power meter is a direct replacement for your Shimano GRX 810 or 600 crankset. It uses the same 24 mm spindle as your GRX crankset so it will fit your current bottom bracket without any changes. This makes installation very easy. In addition, it allows you to mount your 1x or 2x GRX chainrings and uses an exact GRX Q factor.
power2max NGeco ROTOR ALDHU 24MM Power Meter for GRX Chainrings
power2max ROTOR ALDHU 24MM Gravel Power Meter Crankset
This power2max is also a direct replacement for your Shimano GRX 810 or 600 crankset. It too uses the same 24MM spindle as your GRX crankset, so it fits your current bottom bracket without any changes. However, unlike the option above, it comes with power2max 1x or 2x gravel chainrings. In addition, it gives you a narrow road Q factor vs. the slightly wider Q factor inherent in GRX cranks.
power2max NGeco ROTOR ALDHU 24MM Gravel Power Meter Crankset
Pros: Moderately priced, VERY reliable, measures both legs
Cons: Have to change out your crankset
Crankset Power Meter (Crank Arm Based)
4iiii PRECISION PRO Shimano GRX RX810 Dual-Sided Power Meter
The 4iiii PRECISION PRO Shimano GRX RX810 is a dual-sided GRX crankset that measures power from both legs. In addition, because it has a sensor on each crank arm, it can also measure independent left/right power. The 4iiii is also lightweight, only adding about 20 grams to the Shimano GRX crankset. The power meter is compatible with both ANT+ and Bluetooth SMART devices and is accurate to +/- 1.0%. This power meter can be installed on a GRX 810 or a GRX 600 drivetrain.
4iiii PRECISION PRO Shimano GRX RX810 Dual-Sided Power Meter
Pros: Measures both legs, provides independent left/right power
Cons: More expensive, have to change out your crankset
Power Meter Pedals
MTB power meter pedals can be installed on any gravel crankset. We have the Garmin Rally XC, SRM X-Power and SRM X-Power Flat power meter pedals.
Pros: Easy to install, works on any bike, can move from bike to bike, don’t have to change crankset
Cons: None