I bought a 78 GMC 6500 dump truck a few years ago. I paid for it and started down the road for the drive home. Less than a mile down the road I had to pull over to check on a "flat tire". Surprisingly I had no flats, then I remembered about bias ply tires not being round for a little while. They were so out of round I was sure I had not one but two flats on the rear. After about 30 minutes they were smooth and round.
I have run both bias and radial. If buying new tires I will but radials. If I find a great deal on some bias ply tires, like under $100 for a set, I will run then on my old stuff. But only radials for my new (90's) car.
Grigg