Originally Posted by
HTupolev
I'd be surprised if the exact angle doesn't involve some guesswork, but pushing down versus pulling up at any particular point in the stroke should be detectable as long as the power meter correctly identifies the overall sequencing of the pedal stroke (which should be possible in pretty much any situation where the rider isn't deliberately trying to confuse the power meter).
Also, weighting a pedal on the upstroke is not necessarily any more calories expended. If your leg is actually using its muscles to push down during the upstroke, sure, but that's bizarre behavior and certainly not implied. Weighting the pedal merely implies that it hasn't been fully unweighted! And there's hardly strong evidence that it's more energy-efficient to overcome this fully with the hip flexors versus having the downstroke of the opposite leg contribute.
The most important thing to know is pedal based power meters are as accurate (1-2%) as anything else. With circular chain rings.
I've only used Vectors, any time you touch them with anything but a cleat, you have to go through a procedure to set/calibrate the angle they're installed.
Anyway, back to the original question. Say I'm applying 300 watts to the pedals, in a weird stroke, we're asking if only 200 (or whatever) watts reach the hub and road. Where do the rest go - as a result of pedal stroke? There will be drive train losses, that's why pedals read slightly higher than hubs, but we're taking about whether a pedal stroke can increase the loss. And I don't see how it could?