Car tires, ones that the size starts with "P" will not have the load capacity to support the load and forces required of a travel trailer of any type. Side walls flex a lot more on a trailer than on a car. Most cars weigh less than 3000#'s now in an effort to increase fuel economy. Passenger car tire are just not designed to do the job on a trailer. My older Overlander weighs in at 5000#'s. The newer an Airstream the more it weighs as the company made them wider and added more features. An trailers of all types tend to gain weight as they age. Things get left in the trailer and it will weigh more.
1966 Mercury Park Lane 4 DR Breezeway 410 4V, C-6, 2.80 - Streamless.
1966 Lincoln 4 door Convertible 462 4V 1971 Ford LTD Convertible 429 4V Phoenix ~ Yeah it's hot however it's a dry heat!