Car hauler trailers

DOT allows truck tires on trailer as long as they are de-rated properly for load ratings. IIRC it's something along the line of 80% of posted load rating

Most trailer tires, especially the 205/75/15's are total trash.
I bought two extra wheels when I bought my trailer and it came with one spare. So now I have 3. I usually don’t tow without 2 of them with me.