I would just take them to a tire shop and have them take a look. Probably will just remove the tires from the rims, clean the rims and re-install the tires.
It's unlikely it is because of the tire size. 10.5 and 9.5 tires will fit fine on your rims, if you have either 15x7'' or 15x8'' rims, which you more than likely do, as they were the stock sizes.