Ill have to look into the other 2 brands posted above but in my searches, the only D load rated 14" trailer tire is the Kumho 857 and I highly reccomend them. Have 3 trailers and many bad tire experiences, mostly with Goodyear Marathons, but the Kumhos are awesome.
They wear like iron and have the best load capacity.
I put a lot of miles on my snowmobile trailer and the Kumhos get abused on it. From 80mph road trips for days to overloaded trailer towed up rocky forest roads they hold up great.
Just tugged that trailer 2400 mi to AK during frost heave season. Trailer was over its axle rating. Actually wore thru the floor plywood with the tires from bouncing over all the bumps. Tires still look like new and have over 10k mi on them.