I have a Mustang GT, 4.6 L engine, produced in 2010.
It came with four Pirelli's, 245/45/R19, all season tires. These were not very useful in Swiss winters, and I changed them for winter only Michelin Pilot Alpin. These have the same dimensions as original Pirelli's. I inflate them to recommended pressure of 2.2 bar (32 psi), and all is fine.
I was hesitant to run these winter tires all year around, and have therefore purchased another set of 18" rims (9" wide in front 10" rear), and mounted Pirelli PZero Rosso, 255/45/R18 99Y in front, and 285/40/R18 101Y rear.
How should I adjust the pressure for these new set of tires?
P.S. My mechanic recommended 2.5 bar in all (36 psi), but this led to excessive rear in the middle of the front tires - indicating over-inflation.