I may be wide of the mark here but I would guess that the tyre would be one of the last places that ice would form, mainly because of it being made of rubber, which is a significantly better insulator than the metal of the airframe. I would therefore think that it would retain its temperature above freezing marginally longer than the wing, for instance.
Also it being black, and therefore more able to absorb heat, it would perhaps be at a slightly higher temperature than the white parts of the plane to start with.
Just my musings.