the trailer tires have more plys in the side walls than the truck or passenger tires for that matter...the truck and passenger tire are designed to ride smoother than trailer tires sorta like haveing shock asorbers built in to the tires...the trailer tires are built to carry loads that the truck and passenger tires are not and have to not sway as much in order to do that.....it keeps the trailers on track and makes them track better behind the tow vehicle.......
regards
woody
regards
woody