I found some information about your trailer. Forest River offered optional 16” wheels and tires for your unit, both steel or custom wheels. Surprisingly they did not recommend a particular tire which would indicate they left the door open for individuals to make their own choice because just about any 16” LRE tire is going to provide you with more load capacity then the OE tires.
For your part of the world you may want to consider the upgrade to the 16” wheels & tires and get a tread pattern similar to the Goodyear Wrangler All-Terrain Adventure with Kevlar, size LT215/85R16E rated at 2680# at 80 psi. That tread pattern is very similar to most ST bias tire tread designs.
FastEagle