I went 1200 miles to Mouse world quite a few years ago with weenie tires like that on a popup. Blew 3 on the way down. Turned out I was going over 65 back then. Those tires just don't like speeds over 65!
You might have to order them in from somewhere else like an online tire place. Check your available space around the tires and see if you can go up one size. Get a TPMS system. Stay under 65.
Not sure if the Kenda Karrier ST tires come that small. On some of the bigger ones they rate them 80 mph.
Goodyear Endurance don't come that small.
Etrailer has them in load range D, mounted on new wheels for $75 65mph rated Kendas.
If you have space , width and height this one is 81 mph, carries more weight, better tire with rim$100