Been there, done that.
I just had to replace the the tires on my trailer and went through the some issue. The advice I got was that the bias ply have a stiffer sidewall and will tow better/smoother with less sway, hence the reason most trailers use them. Although they do tend to run hotter than radials. The advice I give is check around with some of the smaller tire dealers around, not the Goodyear/Firestone dealers. The dealer I went to didn't carry them, but ordered them and had them in in 2-3 days. On a side note, my spare is a radial, as I had a tire throw its tread on a trip, and all I could replace it with was a radial. I didn't want to throw it away, cause it's like new, but I don't recommend mixing bias/radials. T J
