The information and charts is useful-but you also have to take into account the rim "cavity". For example, I own a set of HED Ardennes that are designed for 23 tires but are a little wider than a normal rim. Thus, the tire air pressure needs to be a little lower for comparable results.

Also, I have to go with what feels right. That seems to vary from wheel to wheel. I can run a higher pressure in some wheels that others due to different spoke materials.

A guy at a LBS once told me that the maximum pressure was not the mandatory pressure.

Still I prefer to ride on hard tires. My globe has 38 tires and less than 80 lbs makes me feel like I'm peddling uphill. My 27" Raleigh rides real nice on about 90 lbs, and I'm 260 lbs.

Thanks for the info. Here is a link to Sheldon Brown's website discussing tires, pressure. width, rolling resistance and etc. http://www.sheldonbrown.com/tires.html