Load Range D tire confusion

Tire load size. Personally I would recommend moving up to a "E" rated tire if you have the room with your trailer. I prefer to have extra pay load with my tires even it is more than my trailer needs. I used to run "E" rated tires on my 5th wheel but switched to "G" rated. They felt more stable travling down the road and lasted longer. I replace my tires every 5 yrs. regardless how they look or how much tread is left. Having a blow out with your trailer can be dangerious and do some costly damage to your trailer from my own experience.