On a 15 x 8 rim, I would run about 30 psi street and 15 psi off road. For a 15 x 7, I would drop the street pressure a little.
If you do some searching you can find a link to the chalk test, which is really the best way to set you psi.
You Gotta Hit It Harder Than That!
1998 SE, 4 Gerbils , 5 speed,
D30 Front, Diff Guards, QD's,
3" Black Diamond springs, Rough Country LCAs,
Pro Comp es3000's, 2" bl, 8,000lb winch,
TB spacer, K&N, Electric Fan, hand throttle,
CB, Seat covers, chopped bumper,
33 x 12.50 Truxus MTs, AR wheels,
Rocker guards, Lights, High Lift ...
[COLOR=darkred]Certain Death Jeep Club Member #2[ /COLOR]
2002 WJ 31x11x16 Thornbirds, Westin Safari Bar