[need4speed]

See if you can get access to a tire pyrometer (probe type) and measure the inside, outside, and center tread of the tires. Hotter in the center means too much pressure, hotter on the inside/outside edges means too little pressure both of which mean loss of contact patch and traction. Temps should be fairly close across the entire tire when pressure is correct. This assumes that you are not running any aggressive camber settings and that your alignment is correct. Once you get the temps close to the same you can fine tune from there depending on conditions and car oversteer/understeer. You can find instructions on using a pyrometer on a number of web sites with more comprehensive explanations than I have provided. Hope this is helpful.