26 Inch Wheel - wrong speed and watts?


I have an issue I am hoping to get help with? I have started using zwift ios. I have a 26 inch mtb with a gatorskin slick. I am using garmin speed and cadence sensor and It is running through a jet black z1 trainer - Which is a supported trainer. My settings (on zwift when I paired) are for a 26 inch wheel. But when I ride I am averaging 20ks difference on zwift than on my garmen watch. I am also pushing 500 watts… Which I am not capable of… Obviously I have buggered up the settings. Any suggestions that may rectify this?? Thanks in advance

David - I see you submitted a ticket, so we’ll work with you further there - I don’t see anything obvious from your account history that would cause issues.

For anyone else experiencing issues, make sure you’ve gone through our recommended setup guidelines and contact usif you’re still having issues after that.