There was a thread about this in the Mechanic's forum here:
http://www.bikeforums.net/showthread...c-Open-Pro-Rim

In it a user named blandin posted this:

From the Mavic Web site.

Tire dimensions and maximum inflation pressure

TIRE SIZE MAXIMUM PRESSURE

mm bars psi

19 10.00 146.00

23 9.50 138.00

25 9.00 131.00

28 8.00 117.00

Hope that helps!
-Bob