Goodyear G60X15 lasted over 20K when new. Drag raced a lot and lasted longer than the factory clutch. I never bought radials until '73 or so because they were JUNK. If you had any kind of problem and they went flat they looked as if someone had used a crash axe on them. In '73 they began putting radials on cars from the factory and they still weren't very good for a couple of years. Tread separation was the biggest problem. My fiberglass belted tires lasted longer, didn't have tred separation and when went flat I could get them fixed.
By the way, I sold tires for a living at the time. I saw all kinds of tires come in and in areas where there was limited pavement the fb belted non raidal tire was best. When I moved in '75 I bought my first set of radials and never looked back. I will probably put non radials on the car when done
Non belted tires didn't last but 10-15K at the best. Just my .02
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JLP
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