[quote=chazzwazzer][quote=aerobear]wahoo seems to have a cadence issue in general. do you see a cadence of 254? (guessing its a range of 0-255 due to being 8-bit). have seen that only in wahoo’s app and on their head units.
pretty much any head unit will take 2-5 seconds to pick up. in general it is not missing data. if you just watch it, there should be an equal delay to when it stops showing data when you start coasting.
whether missing data is in the file or not - depends on the unit. i’m unsure on wahoo. with ant+, each data packet overlaps by a few seconds (it takes a few seconds for accumulated torque counts to roll over and it tracks rotations based on event count, which prevents it from seeing a gap in data and sudden high count as a spike), so something 1-3 seconds long can be backfilled when it picks up another packet. there older units didn’t have the processing power to do this, but everything 810 and newer does. the stages head unit does the same thing. i ride inside occasionally in a workout room full of sensors (stationary bikes with power, kickrs that are blasting out ant+ whenever plugged in, other people riding with HR straps, etc) and it causes a lot of intereference, but always end up with 100% of the data in the file, just some drops here and there on teh display. kind of unavoidable in that kind of environment.[/quote]
Never seen a cadence that high, no. Mostly I’ll be pedaling at a cadence I know is as steady as I can go (indoors), and it’ll jump 5-10 rpm. The average works out of course but I’ll watch it bounce and know I didn’t go from 98 to 105 to 99 in the space of five strokes. I’m curious to add my Garmin cadence sensor back in the mix, at some point.
I’ll watch for the drop off delay and check my files eventually. Thanks for suggesting that and filling us in the packet timing stuff, that’s good to know. I only started with this stuff in November and mostly just hand off files to my coach.[/quote]
It could be a rounding error of some kind on the part of the wahoo then… In my own experience that cadence data is super reliable from the accelerator in normal usage (i.e. not rowdy mtbing or something that gets super bumpy or extremely slow/high torque stuff like a standing start). As kind of mentioned, watts and rpms aren’t actually calculated by the meter, but sent out as event count and event time and accumulated torque is send along side of that, so the head unit itself makes that into power and rpm by figuring out how much torque was accumulated between events and how fast the event was. Downside is that if your cadence values seem off, seems suspicious on the power since torque is multiplied by rpm, but you’re probably right that it ends up averaged out.
Not sure what wahoo’s priority is set to, but on a Garmin it’s actually impossible to record a cadence sensor’s data on top of a power meter. It’ll only record the cadence from the power meter (unless it’s a hub/power tap).