A worldwide shortage of large tires is affecting some distributors in Eastern Carolina. Officials with Potter Tire and Oil in Aurora say during the past year they've noticed a significant drop in availability of certain types of large tires used on trucks that work in mines and swamps. Brian Potter, one of the company's owners, also says he's noticed a substantial increase in cost as well. Potter says the shortage is due to a variety of factors. Some large tires cost several thousand dollars a piece.