I've got a P2M (S Type) with Rotor Q rings and a Powertap G3 - I've never done any specific testing in relation to the oval rings and have never run the P2M with round rings as it came with the ovals second hand.
I have run them at the same time and they tracked pretty much exactly over a 30min ride with varying power between 0 & 500W. The P2M was slightly higher overall (@2%) on average but I would expect that given it is further up the drivetrain and that's also within the accuracy level of the two meters combined.
If the oval rings were inflating the power what kind of variance would you expect to see (a previous poster mentioned 20W) or is it more complicated than that and my N=1 doesn't prove anything either way?
Ps. I bought them both second hand, used them year round in all weather (more so the Powertap) and neither has ever missed a beat so would happily recommend either.
I have run them at the same time and they tracked pretty much exactly over a 30min ride with varying power between 0 & 500W. The P2M was slightly higher overall (@2%) on average but I would expect that given it is further up the drivetrain and that's also within the accuracy level of the two meters combined.
If the oval rings were inflating the power what kind of variance would you expect to see (a previous poster mentioned 20W) or is it more complicated than that and my N=1 doesn't prove anything either way?
Ps. I bought them both second hand, used them year round in all weather (more so the Powertap) and neither has ever missed a beat so would happily recommend either.