So why are they more expensive? What special features do they have over a quality light truck/highway tire?

I am looking to buy two as 2nd and 3rd spares for the upcoming trip but I have only bought one trailer tire in my life and it was a carlisle as a spare for my old hauler 5 years ago. They were $65 back then...now they are 100 each. WTF?

The tires on my trailer do look great for tread, but are approaching 6 years old and don't have any cord separations showing and are in decent shape for having a guessed 10,000+ miles on them.

Read the mixed reviews on the GY Marathons, and I had great luck with the Kumho's on my old enclosed trailer. Looking for a C range or regular truck tire for what looks like a max of 4700lb trailer/car combo.

Gracias!