Tyre pressure range will be written on the side wall of each tyre, and varies entirely between tyres, widths, tread patterns, intended usage, manufacturers and personal preference.
Personally, I run them hard, as the SMGTe has front/rear suspension to suck up the bumps.
If the declared range of pressure is 55 - 80psi (for example), I normally put it at about 75.
Front and rear will likely vary, and all tubes lose pressure over time.
Andy.