You don't need an"RV tire store" - just a tire store. If the tires on the coach are 19.5 or 22.5", I would suggest a commercial (truck) tire shop for better prices and service, but regular tire shops can order them too.
Former owner of 2004 American Tradition and several other RVs
Home is in the Ocala Nat'l Forest near Ocala, FL
Summers in Black Mountain, NC