There are several power meters that will work on a Cannondale MTB crankset:
Left Crank Arm Power Meter
Stages Cycling makes a left side crank arm for 2014 or newer Cannondale Si, Hollowgram Si and Hollowgram SiSL2 cranks. It also fits the Cannondale ONE crankset. This power meter will replace your current left side crank arm and will measure left leg power.
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 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
Spider Power Meters
The power2max NGeco Cannondale MTB Power Meter is one of our go to power meters for Cannondale MTB cranksets. It’s a superb power meter in that it’s accurate, extremely durable, measures the power from both legs, is reasonably priced and allows you to keep your current Cannondale crankset.
The power2max NGeco Cannondale MTB Power Meter is compatible with Cannondale SI, SISL or SISL2 cranksets, as well as the Cannondale ONE. Please note, the power2max uses a 104 BCD chainring configuration. So you will need a power2max compatible MTB chainring as well.
The Sigeyi AXO Cannondale MTB Power Meter is also a spider-based power meter, very similar to the power2max above. The Sigeyi is compatible with the same Cannondale cranksets and measures power from both legs, however it’s a bit more affordable than the power2max. The Sigeyi also uses a 104 BCD chainring configuration and requires a compatible chainring.
Pros: Moderately priced, VERY reliable, don’t have to change crankset, measures both legs
Power Meter Pedals
MTB power meter pedals are also an option as they can easily be installed on any MTB crankset. We have the Garmin Rally XC, SRM X-Power and SRM X-Power Flat Pedals.
Pros: Easy to install, works on any bike, can move from bike to bike, don’t have to change crankset
Cons: Some versions are pricey