Special Trailer Tires

Casitas with the factory “high rise” option are delivered with either Goodyear Endurance ST205/75R15 load range D tires, or Goodyear Endurance ST225/75R15 load range E tires, depending on supply chain availability. The ST stands for "special trailer" tire. There are differences in the driving requirements between the tires on your trailer and those on the car or light truck you use to tow it. Therefore, there are distinct differences between the way trailer tires and tow vehicle tires are engineered.

Your tow vehicle is a leader, which means traction is a key focus in the design of its tires. Typical passenger and light truck tires are developed with features like flexible sidewalls and long-lasting tread designs. This is because your tires accompany the steering and braking systems on your car and truck and transmit traction power from its drivetrain to the road. Traction allows your tow vehicle to accelerate down the road, turn around the corner and brake to a stop. Another important consideration is tow vehicle tires are designed for ride comfort, which is achieved in part by allowing their sidewalls to flex.

Your trailer is a follower, which often makes tire sidewall flexing a negative. Sidewall flexing on trailers, especially high center of gravity RVs that carry heavy loads, is a primary cause of trailer sway. Typical passenger tires with flexible sidewalls can accentuate trailer sway problems.

Trailers will be more stable and pull better on tires designed specifically for trailer use. Since Special Trailer (ST) tires are constructed with heavier duty materials, they are tougher than typical passenger vehicle tires.