You have several power meter options depending on the version of your SRAM Rival BB30/GXP crankset. Please see below for details.
Left Crank Arm Power Meter
Stages Carbon for SRAM BB30 Power Meter
The Stages Carbon SRAM BB30 Power Meter is compatible with SRAM Rival 1 and Rival 22 BB30 cranksets when used with Stages Spindle B. With this power meter, you swap out your current left crank arm and spindle for the Stages ones and you are good to go.

Stages Carbon for SRAM BB30 Power Meter
Stages Carbon GXP for SRAM Road Power Meter
This Stages power meter is made to work with most SRAM Rival GXP cranks. With this power meter, you swap out your current left crank arm and spindle for the Stages ones and you are good to go.

Stages Carbon GXP for SRAM Road 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. 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
Spider-Based Power Meter
power2max NGeco SRAM Road Power Meter
The power2max NGeco SRAM Road Power Meter is one of our go-to power meters for SRAM Rival 3-bolt road cranksets. It’s a superb power meter in that it’s accurate, extremely durable, measures power from both legs, is reasonably priced and allows you to keep your current SRAM crankset.

power2max NGeco SRAM Road Power Meter
IMPORTANT: This power meter fits older SRAM Rival cranksets that use the direct mount interface. These cranks can be identified by 3 bolts located on the inside of the spider which are used to secure the spider or chainring to the crank arm. Please see the image below.
Please also note, this power meter is not compatible with SRAM 1X 40T chainrings (however we do sell Praxis 1X 40T chainrings that will work).
Pros: Moderately priced, VERY reliable, don’t have to change crankset, measures both legs
Cons: None
Power Meter Pedals
Power meter pedals can be installed on any crankset. They are reliable, accurate, easy to install and can be moved between bikes. We carry every power meter pedal available including ones from Favero, Garmin, SRM/LOOK and Wahoo. This includes both single- and dual-sided versions as well as pedals for SPD-SL, LOOK Keo and Speedplay cleats.
Pros: Easy to install, works on any bike, can move from bike to bike, don’t have to change crankset
Cons: None