The factory recommendations were 24psi f/r for city driving. For over 75mph, add 4psi not to exceed 32psi. Max load was like 30 frt/32 rr on non-station wagons.
P-Metric radials went to 35psi max for fuel economy reasons. Modern radials usually will go to about 45-50psi cold, but that does not mean you have to run that much.
Back in the late 1960s, on our '66 Newport 4dr Town Sedan, I figured the weight distribution f/r and then found a chart in an old CAR LIFE magazine that had tire capacities at various tire pressures. I used that to craft my own tire pressures for normal driving, with the inflation pressures reflecting the "axle load" of the car. Using 28psi as the base rear psi, I added 2psi to that for the front (front end is heavier). This resulted in completely EVEN tire wear f/r. Plus with more air in the front, better steering response (which was already better than many cars anyway). If the car was going to haul people, then I went up to 32 frt/30 rr and still had plenty of load capacity in the tires vs how much the car weighed. With those results, that has been my pressure orientation every since then. Not what the factory recommended, but what I found to work best.
Who knows why the tire shop put that much air pressure in the tires, past getting the beads to seal initially. I'd try 35psi frt/33psi rr and see how that goes. I'm suspecting you have 14x5.5" wheels?
In many cases, the Hankooks might be classified as "modern rubber" rather than the dreaded "old school" rubber.
Just my thoughts and experiences,
CBODY67
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