Is that to imply that tubes marketed as "radial tubes" are better quality as they are more flexible and thicker, and ideally should be used in preference to "standard tubes "whatever tire you're using?Main differences are that radial tubes are both thicker and more flexible in order to withstand the higher amount of flexing that occurs in radial tires as compared to bias ply.
My experience is in alignment with Randy, Post #2. Radial tubes are thicker. Because of the increased flexibility, radial tires tend to run hotter, although running higher tire pressure can reduce the temperature. Aircraft Spruce has tire talc which can reduce the rubbing friction wear and heat on the tubes. I don't see any harm in using the radial tubes in bias ply tires.
Where are these radial tubes made?