Tire Pressure Adjustment for Upsized Wheels?

Question

I have upsized my car wheels from 16" to 17". With stock wheels, the tire pressure placard says 230kpa. What should be the adjusted pressure with a +1 upgrade (assuming all else the same)? Please provide reasons as well.

Thanks.

Stock Tire: 215/60R 16 95H
New Tire: 225/50R 17 94V

Also, what has it got to do with load index. http://www.tirereview.com/?type=art&id=5278&

Answer 1

If the overall dimension of the wheel/tire package does not change(i.e. P195/70R14 to P205/65R15), no pressure change is needed, however, if the overall dimension IS changed, a pressure increase of 3 psi, or approximately 7 kpa is recommended.
Do not exceed the parameters given by the vehicle manufacturer.
Consult your local tire professional for advice.

Answer 2

As long as the section (tread) width and overall diameter of the tire are the same, run the same pressures specified by the manufacturer of the vehicle for stock tires (this info can be found on the load info label, usually on the inside of the driver's side door). You are running the same size contact patch, so the pressure should be the same. You can verify this on looking at the label (as I have) on cars where different rim sizes were available as an option. It lists the same pressure for both sizes as long as the tread width is unchanged.