never go to discount tires (america tire) for any rim/tire/work. i just found out after a week, the pressure on the new 18's are so unbelieveable.
Left Front: 39 psi
Left Rear: 34
Right Front: 40
Right Rear: 45
no wonder the ride was so rough. It caused me a headache on 20-mile trips to commute. I re-adjusted all to 34 psi and it rides similarly to the stock 16's. The comfort is back now.