Bias ply vs Radials:
Bias is good for local towing, rougher roads, lousy boat ramps, because the sidewalls are usually about 2x as thick as a radial. Most radials other than a full steel tire have only a 2 ply polyester sidewall. A Load Range D bias tire has an actual 4 ply sidewall (but rated as an 8 ply tire).
Bias also has no steel belts, so when they fail they don't beat the trailer and boat up with steel strands
Radials advantage is they run a lot cooler so if you tow at high speeds especially in hot weather they are definitely better than a bias tire. However, if you can keep your towing speed to about 55-60 mph I don't think you'll blow up a properly inflated and not overloaded bias tire.
Last thing, a radial tire is a lot more complex to construct than a bias tire. The bonding of the steel belts to the carcass is critical, and if not done right centrifugal force will cause a failure. Sometimes you see a cheap radial tire not even mounted, a spare that is, that blew up due to poor bonding of the steel belts to the internal structure.
Local towing, bias is fine if it meets your load requirements.
Highway towing, do not buy cheap radials, I would use the GY Endurance, or maybe the Kenda Karrier if the GY wasn't available. Other choices are Carlisle, or Hankook. Kenda has been in business a LONG time, they are based in Taiwan and manufacture tires all over SE Asia and also have some operations here in the US. Last set of tires I got from them were made in Vietnam! Others, Taiwan or China. No failures with any of them not even a flat, and that's over 20 years of using them.
