BCA4

for a relatively unladen car, what is the optimum tire pressure for 225/50/16s? I am running 225/50/16 Pirelli P7000SS, currently at 32psi. (Having driven 4x4s, I have an understanding re: tire volume vs. vehicle weight and know that larger tires (on same vehicle) should be run at lower pressure due to the higher volume of air. Running an unnecessarily high pressure in a larger tire will lead to a high spot in the tread which results in poor handling and treadwear.) I gather there is some leeway, however what is the recommended pressure for the 225/50/16 on an A4? Thoughts, comments?

Thanks