I have the same model ACE. Mine calls for 82 psi for all tires. I got it weighed fully loaded with the toad attached. I was about 1000 lb under for each the front and back axles. I dropped the psi to 78 or 80 psi and it improved the handling greatly. I still get pushed a little when a semi passes but not as bad as it was.
I contacted Goodyear about recommendions and all they gave me was a bunch of BS. I guess there is a lot of legalize involve with them in recommending a psi.
Hope you get it solved with out too much expense.
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