Zwift game not measuring Sensor Speed

See the linked (attached) screen shot, the Speed Sensor screen measures 15mph, my Garmin Edge measures 15.3 mph, the Zwift game measures 0 mph with 0 ft elevation.

Any ideas on how to sync it all up?

You have not started the ride so your speed would be 0.

You cannot compare your Zwift speed to the speed displayed on the Garmin Edge, the Garmin does not know about the virtual elevation changes. The 2 will hardly ever match.

Just so you know, speed within Zwift for zPower (that is what you are using) is determined by your rear wheel speed and the power curve of your trainer and that is converted to watts. With the watts, your in-game weight, in-game bike used, in-game drafting and virtual elevation changes your in-game speed is determined.

The mph on the Pairing screen seems to match the Garmin mph, but when I’m in the game, the speed often goes to 2 or 3 mph or seems to think I’ve stopped when I haven’t. I selected a flat route, to test the speed. It’s been working well except in the last month or so. I’m using an ANT+ on a MacBook Pro 10.13.5, with Fluid 2 trainer.  I’ve reset the garmin sensor, moved the USB dongle cord to a different USB port, unplugged and replugged the ANT+, zapped the PRAM, the speed doesn’t seem to be measured accurately.


You might want to submit a ticket:

I did, thanks

I unpaired the Cadence (on the Paired Devices screen) - seems to have fixed the issue. thanks.

I replaced the cadence magnet with two Neodymium Disc Magnets, everything seems to be back to normal. Game speed works with both Speed Sensor and Cadence paired. 


Thanks for a great game.