Latest 44+ B78 13 Trailer Tires
Latest 44+ B78 13 Trailer Tires. Our trailer wheels and trailer tires have been rigorously tested, to ensure that they exceed department of transportation standards. Under us rules a trailer tire would be marked st meaning special trailer service not for use on a passenger vehicle.tr is the dot know that most all trailer tires, with an st before the tire size, are rated for max. Customs services and international tracking provided.