The only problem I had with the bias ply tires were the wear factor I never got more than 10 to 12 thousand miles out of them. You are right they sure could squeal and really smoke them.
I just found a N50x15 on my property. I don't remember the name on the tire but it was raised white letter. That thing is super wide. I doubt that it is any good anymore don't know how long it has been down there. Has some tread left on it but prob. dry rotted.
totally agree with all the comments, the trim ring on the right is def. a molar ring from that period. Maybe try and put your knee up against one side while you beat the opposite side with your palm or a rubber mallet.