What was found
JFK - CREW REPORTED ON TAKEOFF LOUD BANG ON NOSE GEAR HEARD. BANG WAS HEARD PRIOR TO ROTATION. VIBRATION FELT DURING RETRACTION. EMERGENCY DECLARED FLIGHT LANDED JFK WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. ACCOMPLISHED INSPECTION OF NOSE GEAR AND NO DEFECTS NOTED. REPLACED RIGHT AND LEFT NOSE TIRES AND ACCOMPLISHED FULL NOSE GEAR STRUT SERVICE AND LUBED NOSE GEAR. SYSTEM GROUND CHECK NORMAL OPERATION.