The easiest way to choose replacement trailer tires is to use the information imprinted on the sidewalls of the existing tires on the trailer. This information denotes the tire?s purpose, size, dimensions, load capacity, and speed and temperature ratings.
The series of numbers and letters on the sidewall is useful in buying replacement tires. Buyers use the first letter to identify the tire?s intended type of vehicle or service. Trailer tires generally begin with the letters ?ST,? which indicates ?Special Trailer Service.? Other information on the tire?s sidewall includes the section width, sidewall aspect ratio, internal construction, speed rating, and tire and wheel diameters.