Re: Passenger tires ok?
There are 16" ST tires made. I've never seen one in person. I'm such a big fan of Michelin XPS tires that it's the only tire I'll put on a trailer with 16" wheels.
16.5" and bigger tires have no distinction, they are all position tires.
My horse trailer has 15" tires and it came with LT tires on it so go figure. They're only 2 years old so I'm not replacing them real soon.