The Kumho Radial 857 is a European designed commercial truck tire built in Korea. There are only three 14” sizes and all in LRD. They are approved by their manufacturer as desirable for trailer service.
Here is the link for information on sizes and the specs.
Anyone using Carlisle radial trailer tires. Discount Tires has 15 inch load range E1 speed rating N for $109.00.
I just checked the tires on my 2013 5th wheel and they are dated 2011. I have few miles on them but will replace them before I go on my next trip.