I bought it last 3 week ago at Walmart (Bell tire).
And today I found that the air is coming out slowly and my tire is almost flat.
I don't know why it happens like this. Even I used only 3 weeks.
I have never hit any things. My tire is still okay. There is no hole.
Anyway, I forgot to tell that my bike is a used bike, and its tire is kind of old. And I'm not sure it is because of this or not.
How to do this?