Trailer tires can typically be found for sale from auto parts stores, though general wholesalers such as Costco and speciality shops such as TrailerTires.com also carry them. Agricultural vehicle stores also sell trailer tires, mainly for vehicles that haul loads around the farm.
Trailer tires are heavy duty tires designed for trailer axles on large vehicles. Although they are mainly used on trailer trucks, these tires are also used on RVs, boat trailers and many vehicles that tow or haul heavy loads. However, they cannot fit on drive or steering axles, so they can't be used arbitrarily in place of regular auto tires.
Many major tire manufacturers, including Good Year, make these tires, and they can be found at auto supply stores as a niche product. For example, Pep Boys, a major auto supply stores, sells trailer tires online. TrailerTires.com focuses exclusively on trailer tires and features an extended range of brands and models. Wholesale supply stores such as Costco also carry them in a much more limited range.