Originally Posted by
patentcad
So I find out yesterday that Garmin units calculate speed via GPS (no wheel sensors needed). Didn't know that before, that's logical.
I was hoping the Fred Brain Trust here could answer a few questions about Garmin units:
" Will they recognize my Cycleops HR strap?
They'll recognize a coded 2.4 GHz strap. They will not recognize the older non-coded strap.
" I presume they will recognize the Ant+ Powertap hub: will that include the cadence and speed calculations?
Yes.
Does the Garmin speed calculation over-ride the Ptap hub speed data?
It prefers the ANT+ speed/cadence sensor, then looks at Powertap numbers, and finally relies on GPS speed.
" If Garmin units calculate speed via GPS, then why do they sell a separate cadence/speed sensor? Is that just for speed?
Cadence, works on a trainer (but is pretty irrelevant with power), works with a bad GPS signal, does not have GPS error.