Moisture inside of a tire can cause excessive pressure build-up and handling problems. After purchasing a new set of mounted tires, the valve cores should be removed to purge out any moisture, and the tire should be inflated with dry air or nitrogen.
When switching from another brand of tires to Hankook tires, it isn’t necessary to change cold or hot inflation pressures. Start with the same settings, and then make adjustments to achieve the desired handling characteristics that the driver prefers.
An approximate hot pressure target for DOT approved R-compound road racing tires is 40 psi. It could be a few pounds less for lighter cars, and a few pounds more for heavier cars. FWD cars may require higher inflation pressure in the front tires. 13” slicks for formula cars and sports racers should initially target for 20 psi hot.
Changing hot inflation pressures to alter the handling characteristics of the car is a fine tuning adjustment. Improving the overall grip level should be done by tuning spring rates, dampers, anti-rollbars, ride heights, alignment settings, etc.