Chances are your tires actually DO have radio emitters in them - tire pressure sensors are wireless and send their measurements out on the 433 MHz band.
I use 433 MHz buttons, switches and sensors for my smart home stuff, so I have a receiver (generic DVB-T SDR dongle) listening, and I can see all the tire pressure signals that passing cars send out.
Nar mate, that's just the poisonous 5G gas escaping the tyre. The tyres are supposed to be flat on the bottom: more contact patch on the road = more grip!