Cranes; Fire trucks; Aerial equipment; Specifications. DI: 39″ diameter; 3″ thick; 50 lbs. Maximum allowable veal force: 1750 lbs. (fully supported nditions) Maximum allowable deflection: 1.5 in; Friction efficient: .29 (will improve as dirt bOkaymes embedded on the surface) Load capacity: 450 psi; Temperature range: -4°F to 113°F