Typically when it comes to replacing a trailer tire I recommend sticking with the same size. Although I do not know the weight capacity of your current tires, we do have the Taskmaster 5.30R12 Radial Trailer Tire - Load Range C # TT53012C. This radial tire has a maximum load of 1,050 lbs at 80 psi with a max speed of 81 mph. It looks like your trailer has a GVWR of 1,995 lbs so these tires will handle that without any issues.
Because of the tire size, it is also possible to go to a 145/80-12... view full answer...