I have a 1978 Sunfish that I have on a trailer. I get my tires from walmart, it has 5 nuts. But the tires don't last much at all. I have already had to replace it twice. Feels like each one is only good for 500 miles or less. The thread just comes off.
Any suggestions for a good quality tire that will last.
I've not tried Wally-world tires, but I get the cheap tire+rim combos from Harbor Freight and the like.
They seem to last for thousands of miles.
It sounds like you may have an alignment problem (bent axle?).
I have a trailer with a trailing-arm suspension (two half axles pivoting at the center instead of a single rigid axle) and it will chew up tires if the alignment is off.
I have bought tire/rim assemblies at West Marine and have been quite happy with them. My tires are now around 8 to 9 years old and are still in very good condition. I have no idea as to how the price compares with other suppliers.