What was found
(CAN) PILOT VERBALLY REPORTED MINOR VIBRATIONS ORIGINATING FROM THE NLG FOR A PERIOD OF APPROXIMATELY 1 MINUTE FOLLOWING TAKEOFF. AFTER INVESTIGATION I NOTICED THAT WHILE SPINNING THE NOSE WHEELS I COULD HEAR DEBRIS INSIDE THE TIRES. AFTER DISASSEMBLING THE NOSE WHEEL, FOUND SEVERAL CHUNKS OF RUBBER THAT WERE MOVING FREELY INSIDE THE TIRE, WHICH WERE UNDOUBTEDLY CAUSING AN IMBALANCE IN THE TIRE ONCE THE NLG LIFTED OFF THE RUNWAY UNTIL THE WHEEL STOPPED ROTATING.