As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAXI, FELT MLG WHEEL VIBRATION AND NR 4 MLG TIRE/WHEEL ASSY WAS CANTED AT AN ANGLE. FOUND NR 4 MLG WHEEL RIM ASSY AND INNER BEARING RACE BROKEN APART. REMOVED AND REPLACED NR 3 AND NR 4 MLG TIRE/WHEEL ASSY'S AND NR 4 BRAKE ASSY PER MM.