flagstaff said:
I have seen some tire threads that will sometimes refer to using LT tires on a trailer.
What's the difference and pros and cons?
It's a controversial topic.
The best information I have been able to find, based primarily on posts from an engineer who worked for several major tire manufacturers during a career spanning over 40 years, is that there are very few differences between LT and ST tires of the same size and ply rating. The main physical difference is a slightly shallower tread to provide better cooling when new, and the tread patterns themselves differ slightly.
ST tires carry higher load ratings, and lower speed ratings, than LT tires of the same size. This is supposed to be because of differences in intended use. The load ratings haven't been updated since the early 1970s and are for the most part based on a short-distance, occasional-use model that hasn't really applied since the 1950s and maybe didn't even apply back then. One of the few things that people on RV forums can agree upon regarding tires is that ST tires, run at their maximum load for extended periods, fail.
People trying to switch to LT tires find that they have trouble getting ones that have high enough load ratings, and so in most cases they switch to larger rims and larger tires. Well, if you switch to larger rims and larger tires, you'll have better luck with your tires whether you use LT or ST tires, just because the tires have more inherent capacity, so the success people have with LT tire conversions doesn't have anything to do with the LT tire. They could have switched to a larger ST tire and had the same results.
Broadly speaking, LT tires are made in larger quantities and therefore in newer production facilities while ST tires, being a specialty item, tend to be produced in smaller and older production facilities. I suppose we could speculate that the quality might be a little more uneven with ST tires as a result.
But the thing to watch is that 16" LT tires aren't produced in the quantities they once were, and will become obsolete relatively soon, because new production trucks have all switched to 17" and larger rims. So the usual 16" rim and LT tire conversion may, in the long term, require a specialty low-volume tire anyway.