It looks like you’re using Bluetooth on Android.
I have never seen a “Tire Size” selection appear before. I can only guess that you selected the “Speed Sensor” option for pairing (right side button). I have never used that button. Hence, I do not know what options it will give you. Anyway, if you want to pair your Kickr, you will need to select the left side button (Power Source).
If the Kickr is already paired to something via Bluetooth, it will not show up. Make sure that nothing else is paired to the Kickr.
If the above is of no help, there is this: