Looking to replace my ST205/75R15 load range C trailer tires. My local tire dealer is offering me Hercules trailer tires, load range D tire in the same size. My existing steel wheels are stamped for the max load of 1870 lbs that the C rated tires are rated to carry at 50 psi, their max inflation, which is the pressure I run in them. The D rated tires will need to be run at 65 psi, which are a max load of around 2300 lbs each tire. My concern is are my wheels rated for 65 psi? I can't find a max pressure rating anywhere on them. The trailer weighs 4500 lbs loaded, so the C rated tires are more than sufficient for the job. Should I continue my search elsewhere to find C rated tires, just to be safe? Tire dealer says, no problem, they'll work, but I'm not so sure. Thanks!