Discrepancy between DCR and fredly. fredly says calibration is automatic. DCR says to calibrate.
Though fredly fills in a great gap missed by DCR, shoe clearance/shimming issues. As a “big-shoed” person with several pairs of road shoes, this is where brick-and-mortar stores can justify themselves to me. I’d love to bring all my shoes in and spend 30 minutes on their fit bike hammering through all my shoes on a demo pair of these Speedplays. To save the hassle of shipping back a pair of power meter pedals with scuff marks on the pod in the event I can’t find a shim setup that makes me happy.
actually, the discrepancy is between ray and i. i added that as an edit to fredly’s article (fredly here is Matthew Hill, who authored our review o this pedal). here is what wahoo says. officially:
POWRLINK ZERO automatically calibrates. With Automatic Calibration, POWRLINK ZERO automatically detects when no force is applied and triggers the zero offset calibration function. To ensure that the calibration is valid some other requirements have to be met, most importantly the bike has to be upright and stationary (which POWRLINK ZERO detects from the accelerometer and gyroscopes measurements.) If these requirements are not met POWRLINK ZERO will discard the result, and look for the next opportunity to calibrate.
now, i had some discussions with fredly about this, just yesterday, because he and i are independently producing comparative power file graphs with our various PMs and smart trainers. fredly pointed out to me that automatic calibration may be an issue when riding stationary. here is what he wrote me:
the “no force applied” part is the key there. That’s coasting, which essentially never actually happens on a trainer, at least not sufficient to trigger calibration.
so, you all can take from this what you want. it seems to me that automatic calibration is a feature of the pedal, but with certain limitations.