Originally Posted by
smashndash
I’d like to warn against left only power meters though. I can’t actually confirm if this is true, but at lower power levels (under threshold), my left leg “drags” a bit. But my left leg kicks in hard at or above threshold. So if I’m trying to do a certain amount of power just under threshold, or if I’m spinning kind of fast, the PM will read low. I’ll make a slight increase in effort, and my left leg will kick in, and the power reading will jump.
I have the same thing except opposite legs. The difference in power output is greater the further below threshold I'm at. At a threshold pace it's usually just 2-3% different between my legs, but I've seen as high as a 60/40 L/R split on efforts well below threshold. Since those efforts aren't meant to be high power I'm not sure if this is a problem I need to work on or not, and I had no idea I rode that way until I got the PM. I totally agree on the left-side-only option being insufficient, though, and as Seattle Forest said, if you really want to know what you're doing then it's dual-sided all the way.