As mentioned, you can put semi tires on your TT but you do not change the axle rating.
Most people perceive a load range D being stronger than a C rated or a E stronger than a D. They will carry more weight but they do not ride as smooth, resist road hazards or provide a magic cure for everyday tire issues.
Changing to D rated tires does give a measure of protection, as it allows the loss of tire pressure while still maintaining weight rating. My D rated tires at 65 psi still carry a C rating a 55 psi.
Also, upgrading to a D rating is like chicken soup, it cannot hurt and feeds our bigger is better psyche.
