19.5 tire wear

I hear 7-10 years based on weathering. My trucks are not garaged, so the tires are exposed their entire lives. I fully expect 70-80K out my current tires based on the current wear which would put life about twice as long as an LT tire.

My ST trailer tires are lasting only about 4 years and 25-30k miles - I am debating trying LT tires on my trailer next spring...