I am having problems with the inaccurate cadence reading using Saris H3 trainer. I will have a cadence greater than 90 and it will read it for a short time then drop to 70s and then the 50s then climb back up, but mainly under read the cadence.
I have the same issue with both of my H3’s. If Cadence is important (workouts?) get an external sensor.
Did you try using the Saris app to make sure software is up to date and to calibrate?
I have an external Garmin sensor and it does not show up to pair.
I tried that before. Did firmware update and calibration and it helped but then it reverted back to its old ways.
How are you connecting to Zwift? If iOS a lot of the Garmin sensors are Ant+ and not BT. Otherwise battery or just a bad sensor could be an issue.
I went low tech–just put an old Cateye wired computer on my bike–problem solved. And, my H3 does transmit cadence accurately some of the time.
I am connected with BT on iOS Mac. When I had a dumb trainer the cadence sensor worked, however Zwift can’t locate it. It’s important to me because my training sessions are focusing on cadence.
Here is all I got for your sensor (I have been using cycling computers for 20+ years) but note I am not familiar with iOS:
Unload the program you used with the dumb trainer.
Try connecting through the companion app
Disconnect the sensor from your head unit/watch if used
Change the battery…leave the battery out for at least 5 minutes to allow full discharge
You could try unloading and reloading Zwift
And that is it…at some point the sensor gods are against you and another sensor is what it will take to appease them.