You have a couple of options for your RS500 or RS510 crankset as outlined below.
Left Crank Arm Power Meter for Shimano RS500/510
While there isn’t a specific RS500 or RS510 crank arm power meter, you could absolutely use the R7000 power meters made by 4iiii and Stages as the R7000 uses the same interface (Hollowtech II) as the RS510.
Please note, the color of the crank arms won’t be exactly the same (a cosmetic issue only), but most customers are ok with this.
You swap out your current left crank arm for the new power-equipped one and you are good to go.
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)
This is a new crankset (power meter spider, crank arms and spindle), excluding chainrings. power2max makes wonderful power meters. They measure both left and right leg power, are reasonably priced and are as good as it gets in terms of accuracy, reliability and dependability. If you select the 24MM spindle option, it will fit your current bottom bracket (no need to change bottom brackets). Assuming your Shimano RS crankset uses 110 BCD 5-bolt chainrings, if you select the Shimano 110×5 Bolt spider, you should also be able to use your Shimano chainrings on it.
Pros: Moderately priced, VERY reliable, measures both legs
Cons: Have to change your crankset
Power Meter Pedals
Power meter pedals can be installed on any crankset. We have several models to choose from.
Pros: Easy to install, works on any bike, can move from bike to bike, don’t have to change crankset