I’m looking at power meters for a CAAD13, its got a 105 groupset and cannondale SI crank arms. I see stages sells a left side PM for both cannondale hollowgram and standard 105. Does anyone know if one or both of these will work on this bike?
Stages works as does 4iiii who does a left side. I have run both, prefer 4iiii
Standard 105 stages would not work in your case since the bottom bracket is fitting the hollowgram crank.
Therefore you’ll have to go for the SI crank specific model if you want that.
Other option (more expensive though) would be Power2Max - their powermeter is fitted on the drive side. Similar story here, also this one would have to be Cannondale-specific.
Just as @hannes said. You’ll want to match your PM to your crankset and not the rest of the groupset (if doing a left arm or crank spider PM). The way the crank arm fits to the rest of the crankset is different from a Shimano crankset to a Cannondale crankset so you’ll want to be sure you match the same to same.