Thanks, everyone for speaking up.
Sparky: I’m not sure I understand your comment about radials. The Goodyear Marathons, and most other trailer tires are radial design. Are you are saying they throw the belts because they are radials? Are your truck tires radials? I do like your idea of running a D or E load tire. My problem is; to convert my drums to the truck bolt pattern would be cost prohibitive when I could put that expense into new tires. However, you gave me a good idea and I’ll check it out.
Thundersalt: You hit the nail on the head. That is exactly my current condition. Good tread, but sidewall cracking and age are too far beyond a useful life.
Tom: I run my trailer right at GVW and check heat at every fill-up. My Tires are always hot, but most of my towing is down Hwy 5 on 100 deg days. That is the main reason I want a good tire. I’m not sure what G159 is. Is that the tire designation?