truck tires are not trailer tires
There is a code on the side of a tire that gives you alot of information on trailer tires. They are ranked P for passenger, LT for light truck, and ST for trailer tires. Trailer tires are by far the toughest with full rated 6 ply walls. They don't flex much--inflate them to maximum air pressure because the flexing causes them to overhead and separate. They come in Load ranges ABC and D, get range C for your uses, that's about 1800#/tire. Stay away from any other tire, they'll blow and in some states and provinces, if you're caught at an inspection you'll be taken off the road--thye're dangerous. Trailer tires are usually constructed as bias ply but not always--just be sure you get ST load range C or D and inflate them hard and all will be fine.