Lynnmor wrote:
This ST/LT debate goes on and on. Nobody says what the real problem is.
Ok. I'll say it.
The reason for this discussion is that RV tires still fail far too often. We all worry about this.
The real problem IMHO is that RV manufacturers recommend and install tires that aren't rated for the loads they'll have on them in actual use. They size tires so that they're pushed to the limit when the fully loaded trailer is sitting still in a parking lot. As soon as a loaded trailer is towed, those tires are overloaded by the additional dynamic forces that occur. I figure the factory tires on my trailer are overloaded by about 580lbs each when I drive a modest curve at a reasonable speed because the trailer leans to the outside of the curve.
There's plenty of anecdotal evidence that both ST and LT tires can work reliably on trailers. Irrespective of which way one goes, the tires need to be designed to handle all the forces they'll see. This likely means choosing a significantly more robust tire than recommended and installed by the RV manufacturer.
In my case, I've changed to Kumho 857 tires. These are neither ST nor LT, and are designed for rugged trailer use. Speed rating is 99mph. Load rating went from 1760lbs (ST205/75R14 LRC) to 2270lbs (205R14). Unfortunately, they're only available in 14inch sizes.
And, BTW, the wheels and axles are also likely to be overstressed by dynamic forces in typical RV industry products. The tires are just the most visible failure that results from this problem.
