I was skeptical as well when my tireman ask me to add chamber nut on my 2 years old persona

then he jack up the car and he ask to to look.

when i look at it, my tire was slightly

/ \

then he show me the tires. makan 1 side liao.

so after add, the tire become vertical again.

Guess theres some genuine case where we need to add chamber nut.