The Carlisle Radial Trail HD and the Goodyear Endurance are, for the most part, direct competitors with very similar tire construction...
The 225 75R15 LRE size is both brands will carry 2830 lbs @ 80PSI. That is also the maximum weight limit for your wheels, so installing heavier duty tires that require a higher pressure to achieve that bigger load rating would not be compatible with your current wheels.....
There are several "steel cased ST tires" in the 225 75R15 size. The Trans Eagle All Steel ST is one brand:
https://www.bestusedtires.com/transe...SABEgJijvD_BwE It's a Load Range G (14 ply) tire with a load rating of 124 which is 3527 pounds @ 110PSI. Your wheels would not carry that pressure or that load, so to use such a tire, you'd also need 4 new wheels. At $500 for the tires and probably another $500 for the wheels, then the "next weakest link would be the bearings/hubs and axles...
When does the "upgrading" stop ???? It's easy to "spend someone else's money" but if it were me, I'd buy the new Carlisle RT HD's, install them on your existing wheels with metal valve stems, have them balanced and save the rest of that money for insurance premiums (in the event of a tire failure)...