What was found
A NORMAL LAND UP UNTIL, SENSED WHAT FELT LIKE DRAGGING BRAKE ON RT M/G. ONCE SAFELY STOPPED, AND ENG`S SHUT DOWN, CREW EXITED A/C, DISCOVERED RT O/B WHEEL ASSY FLAT TIRE. RETURNED TO A/C TO FIND TWO OTHER TIRES FLATTENED. THESE WERE BOTH RT AND LT INBDS TIRES. PLANE RETURNED TO BASE. ONCE THE WHEEL ASSEMBLIES WERE TAKEN APART FOR TIRE/TUBE REPLACEMENT, DISCOVERED INNER TUBES HAD SPLIT IN A RADIAL DIRECTION ACROSS TUBE. THE FOLLOWING MORNING, MX FOUND 4TH MAIN WHEEL, THE ONE NOT PREVIOUSLY REPLACED, ALSO LOST IT'S AIR OVERNIGHT. A SIMILAR SPLIT WAS FOUND IN INNER TUBE. ALL 4 WHEELS WERE NEW JUDGING FROM CONDITION. A/C FLEW DURATION OF FLT IN EXTREME COLD CONDITIONS (-40'C) AT FL 230.