I can't speak for the Nanco tires but we had the Mission tires replaced that came on our trailer a couple of month's ago. They had begin to show signs of cracking on the sidewalls and two had the belts starting to seperate. If your tires are 3 years old and you don't have metal valve stems that could be a point for failure. Also check the spare.
17 Chevy 3500 DRW 4X4
16 Mobile Suites 36RSSB4
2 Mini Dachshunds
my unit is an 06, I had towmaster tires from the factory, I do keep them covered but this year in the spring I had 2 tires with cracks so I scrapped them all and replaced them with LT tires, if you have the slightest doubt that the tires are no good, just replace them, the peace of mind is well worth the expense.......
Thanks for the answers...I kinda thought that would be the wise choice...we're heading to Myrtle Beach in July - after an out of the way trip to Bristol Tennessee...1000+ miles in a few days each way...better get em' changed