Am NOT a tire engineer...just my opinion on this one
I change out all ST class tires on my trailers over to LT class.
Expensive, as the wheels also need to be changed (in most cases)
Am not of the philosophy that the sidewalls MUST be stiff to resist this force
and why I like LT radials of HIGH aspect ratio as I can find
Down side is that the trailer will have a higher tendency to wiggle the side
walls and I've managed that with the highest ply rating and keep them aired up
to max PSI
Bottom line is that all the trailer suspensions I've ever looked at are El Cheapo
NONE had shocks