The tires that come with a new trailer should have the correct rating. If a tow vehicle can t support some of the trailer weight the tires can be overloaded
if you drive 56-58 mph never exceeding 60 mph and always have correct ctp that will help. Make sure tires have reasonable mfg date...newly bought tires does not mean they are new. Protect them from UV will help. Tires should support no more than 80-85% of max allowable weight and max ctp....if trailer tire goes flat while driving replace all trailer tires on flat side....sooner than later.
ST tires should last up to 5 yrs if cared for properly, that means don t let ctp get below max while being stored....keep tires aired to correct ctp at all times, don t drive fast, keep them uv protected and go by mfg date on tire. You don t know how the delivery driver drove to get your trailer to dealer, but time is money so I would think it would be fast. But at least was empty trailer at probably correct tp...so damage would be minimum...remember going to bigger tires that come on your trailer means more tp and more bounce as you go down the road.....maybe loose cabinets and broken glasses occur when people drive too fast and try to correct with more ply and greater pressure.....good luck, my thoughts are if you have to go faster than 60 mph to get somewhere find a closer place to go to .....your house is with you what is the hurry....
