As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PDX - ON FLIGHT 2126, VIBRATION WAS FELT FROM NOSEWHEEL AFTER TAKEOFF AND ALSO DURING LANDING (OF LESSER MAGNITUDE). PILOT RETURNED AIRCRAFT TO FIELD. MAINTENANCE REMOVED AND REPLACED NLG TIRES NR 1 AND NR 2. OPERATION CHECKS GOOD. AIRCRAFT RETURNED TO SERVICE.