The dealers have to "pair" them to the bike. The system can take 4 monitors so you can have 2 sets of wheels "paired" to the bike.
There's a vid somewhere, youtube I think of a guy who took one apart and replaced the coincell battery and resealed it all with a hot glue gun.
I have a K12S 6" wheel in the garage that I got to put on my GT sometime, to try a 190 tyre instead of the GT's 180