Trailer and Light Truck tires should bear "ST" for Special Trailer or "LT" for Light Truck. If there's "P" its Passenger Tire and NOT designed to operate at the top end of its load rating. "P" does not bear a "Load Range" designation, but both "ST" and "LT" tires will. To bear this out, I looked at the radial tires on our boat trailer. You have a 14" wheels, so if I adapt what the sidewall of my Radial Trailer Tires said, you need labeling like:
ST 205 75 R 14 D Or perhaps the ST205/75R14 in one place and Load Range D somewhere else on the sidewall.
Many use "LT" tires on trailers in place of "ST" (but not the reverse) and that seems OK. Using "P" series on a dolly is not acceptable. And Load Range C (max load rating at 50-psi) is also probably not acceptable. I think dolly tires should be Load Range D, carrying their max rated weight (shown elsewhere on the sidewall) at 65-psi.
A dolly came with our coach when we bought it used. Tires were 13" but only from memory the Load Range was D.
If the tires you bought include that "D" associated with "Load Range" I think you're OK.
Just Do Not, Don't, No way, put Passenger Car tires on that Dolly!
