Tires: Correct pressure for my custom tires, 2006 nissan altima, nissan altima

Question
I recently bought an used 2006 NISSAN Altima 2.5 S. The manufacture recommended tire size is P215/60R16 and pressure is 200KPa(29PSI). But when I bought it, it came with custom tire size of 245/45R18(not P245/45R18). What tire pressure should I use for these custom tires?(I don't want to change these tires). Thanks in advance.

Answer
Shahdat,

You should run the same pressure the placard shows.  This is because the load carrying capacity is ever so slightly larger, but not enough to worry about.

Just be aware that most of the ride and handling characteristics you will be feeling will be from the particular tire you have on - and not from the pressure.  While pressure can indeed change these things, the differences between tires has a much larger affect.