Thing to do is look at the sidewalls. If they show any cracking the rubber has started to deteriorate. If not, they should be okay. But I would hesitate to use them for driving on the highway, heat will greatly accelerate aging on them. When I bought my 52 it had tires on it that were almost 40 years old. I ran those for about 5 years. The rears were Mobil mud & snow. I wore the tread off before the sidewalls failed.
