said by JustBurnt :Sounds like a rim leak to me, depending on what part of the tire is hitting the ground it may leak or not, sometimes it can take days to get low, sometimes it is over-night, the only way to fix it is to have the tire reseated.
I'd expect a rim leak to be more or less constant.
In any case it is a generic, cheap snow tire wheel that will probably have to be discarded (or repainted) once the tire is taken off, due to rust.