This is my second single axle boat trailer that has had odd wear patterns on the passenger side tire. Talked to a crusty old tire guy, and he said not to worry about it too much. According to this guy, it's very common for the passenger side trailer tires to wear like that. Apparently it's from running that tire in the ditch, on the curb, on the shoulder, etc. That doesn't happen on left turns, only right. He checked my alignment anyway, and it was OK. Kinda makes sense............