Special Trailer (“ST”) Tires Goodyear Marathon trailer tires are widely used in a variety of towable trailer applications and are designed and branded as “ST” (Special Trailer) tires.
• Goodyear Marathon Special Trailer tires, with the “ST” size designation, are speed
rated at 65 MPH under normal inflation and load conditions.
• This speed rating is based on Tire and Rim Association loads and inflation pressures for ST trailer tires without a service description for speeds up through 65 mph. (ref: TRA 2013Year Book)
• If Goodyear tires, with the ST designation, are used at
speeds between 66 and 75 mph, we recommend the cold inflation pressure be increased by 10psi above the recommended pressure based on the trailer placard for normal inflation and load conditions.
You should also consult your trailer manufacturer’s Owner’s Manual for maximum operating speed recommendations for the trailer. Increasing the inflation pressure by 10 psi (70 kPa) does not provide any additional load carrying capacity.
Do not exceed the maximum pressure for the wheel or the valve.
If the maximum pressure for the wheel or valve prohibits the increase of inflation pressure, then the 65 mph rated speed must observed as the maximum speed.
It may be necessary to dismount the tire from the wheel to determine the maximum rated inflation for the wheel and valve. *