ST Tire "Plies" Question and a PSI Question

Dayle1 wrote:

Tireman9 wrote:


comments and advice deleted by author. good luck and safe travels.

The only part of this that I have a problem with is ST tire life. If ST's are designed for the unique sheer loading of trailer use, then they should be capable of surviving for more than 3-5 yrs. And if sheer loading is the primary issue with trailers, it would also seem that LT tires used on trailers should have inferior life expectancy compared to purpose designed ST tires. And if LT users are more likely to inflate their trailer tires based on weight while ST users are more likely to inflate to max PSI, then that would further imply worse reliability when using LT tires on a trailer. Yet there seems to be very few issues with using LTs on trailers.

A few yrs ago at a rally I checked the tire stickers on every TT and fiver at the rally. 1/3 specified ST tires, 1/3 specified LT tires and 1/3 did not specify either. Furthermore, most of the ones specifying LTs were heavier, expensive units like DRV. Now if ST tires are really engineered for higher load and specifically higher sheer load, then how could these rv manufacturers specify LTs and not STs??