This was more or less what I was looking for.
However, the problem is the age of the tires, at least here in Germany.
Cars have to be checked by legal law every 2 years by our "TÜV" (technical car check) organisation. Not having this stamp on the number plate- car can not be used in public areas.
Tires older than 8 - 10 years are not allowed to run anymore. Reason: Porosity (too dangerous).
Beside that , guess your tires became really hard rubber due to their age.
What about in the US?
Thx Ralf