These are tire pressures I use for riding under bad conditions heavy snow, ice, ruts. I have the same type of winter tires in two different sizes.

Schwalbe Snow Stud Tires 700x38 mm mounted on 23mm wide rims---Front 20- 25 Psi...Rear 40 Psi

Schwalbe Snow Stud Tires 26 x 2 inch mounted on 36mm wide rims---Front 15-20 Psi...Rear 30-40 Psi

When road conditions are good I inflate them to max pressure which is around 65 PSI...The tires that I am using are about 10 years old and have been discontinued few years ago.