If that car was sitting for more than 6 years, I'd get a new set of tires. Inexpensive insurance in my book.

 

I have a set of tires on my daily driver that feel out of round after it sits for awhile. But they get better after a few miles of driving. But it only sits for a week at a time at most usually.
Terry

 

Same thing here, after a few miles they sort themselves out

 

General Tire, in the late 50's introduced tires with "nygen" cords that were supposed to be superior to all other makes. After the car set for two or three days in the summer they would take a set and flat spot and would smooth out after driving 5 - 10 miles. winters were much worse some times I could drive all day and never get rid of the thumping.

I would expect any tire on a car sitting for prolonged periods would take a set and flat spot and IMHO would be dangerous to drive since the cords would be weaker and prone to give way in a blow out.

 

Are these bias ply tires or radials?

Bias ply tires are far more likely to flat spot and sometimes permanently.

Radial tires, by their nature, flatten out more easily, but usually they recover within 5-10 miles. Some brands/styles don't do it at all, others it occurs more readily.

As already said, age is a factor. Recommendations vary, but after 6-10 years you need to replace. Part of that depends on stored outside vs. inside, storage temperature, etc. Storing a car on jack stands, indoors, temperature limited, is best.

 

I agree with Rick on this. If the tires are bias ply they can take a permanent set, If they are old toss them.