The main cause of tire failure is improper inflation. Always check the cold tire inflation pressures before each trip and at least once a week during the trip for proper inflation levels. "Cold" means that the tires are at the same temperature as the surrounding air, such as when the trailer has been parked overnight. Wheel and tire manufacturers recommend adjusting the air pressure to the trailer manufacturer's recommended cold inflation pressure, in pounds per square inch (PSI) stated on the Trailer 's Federal Certification Label or Tire Placard when the trailer is loaded. Never load a trailer to a weight greater than its gross vehicle weight rating(GVWR). If the tires are inflated to less than the recommended inflation level or the GVWR of the trailer is exceeded, the ability of the tires are inflated to more than the recommended inflation level, handling characteristics of the tow vehicle/trailer combination could be affected.