HouseCallAuto 3/26/2010If my car, with those tires, I would set pressure at 38 psi. 28 is too low. I believe that manufacturers typically go low to improve the ride as the soft tires absorb more road shock. But 28 psi would give you inner and outer edge tire wear.
kzoomn 4/4/2010The chalk lines test is the best way to get the ideal wear pattern. Draw a line across the tire with chalk- Drive about 100yds- Look at the line...If the middle is warn and outsides still chalked- Air them down. If the sides are more warn...air up. When it wears evenly....You are at the ideal pressure for wear patterns. Air up a bit for gas mileage but a stiffer ride or down a bit for a softer ride or offroad adventures.