"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.
•Industry standards dictate that tires with the ST designation are speed rated at 65 MPH (104 km/h) under normal inflation and load conditions.
•Based on these industry standards, if tires with the ST designation are used at speeds between 66 and 75 mph (106 km/h and 121 km/h), it is necessary to increase the cold inflation pressure by 10 psi (69 kPa) above the recommended pressure for the rated maximum load. o Increasing the inflation pressure by 10 psi (69 kPa) does not provide any additional load carrying capacity. o Do not exceed the maximum pressure for the wheel. o If the maximum pressure for the wheel prohibits the increase of air pressure, then the
maximum speed must be restricted to 65 mph (104 km/h). o The cold inflation pressure must not exceed 10 psi (69 kPa) beyond the inflation specified
for the maximum load of the tire."
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