I always carry a spare but have not had to use it. Better luck I guess. Running far and fast, I like to keep tire load to maximum 75% of rating. If I can't get make that goal, I get a higher rated tire... either higher ply rating or bigger. I inflate to rated pressure + 5 psi. I have mostly run trailer tires on my trailers but would not hesitate to run LT.

As general comment, trailer tires are rated at a certain speed and temperature (?? 65 MPH and ?? degrees F). Running hotter or faster de-rates the tires thus the need to have extra capacity.