What you currently have on your trailer are passenger tires that are 27.7" in diameter and 8.5" wide. and a similar size trailer tire is ST205/75R15, which have a diameter of 27.3" and section width of 8.1".
The correct load range will depend on your trailer's GVWR; you will want to have tires that have a combined capacity that exceeds your GVWR. For example, the ST205/75R15 Karrier # AM10244 are load range C tires that have a 1,820 lb capacity at 50 psi so for a tandem axle trailer that... view full answer...