[CSX 4133]

Do check the sidewall ply listed for whatever tire/brand you go with. Many tires (even E rated) have 2ply sidewalls especially in the radial type tires. Get the heaviest, best constructed tire available and be prepared to replace them at least every 3 years. Trailer tires are not like car/truck tires and age/wear far quicker.
Storing your trailer out of the elements will help preserve the tires/trailer, and if you can get your new tires filled with nitrogen they will tend to stay at the correct air pressure longer.

Additionally you can source 12 and even 14 ply trailer tires.