TM10-3930-660-20 13-4. TIRES    -  REPLACE  (Cont’d) The (8) (9) and aligning ring (7) bears on lock ring that prevents its removal. An O-ring positioned between aligning ring (7) rim (b) creates an airtight seal. d. e. f. g. h. Force outer tire bead and aligning ring (7) down towards center of wheel assembly (6) by standing on tire (3) and aligning ring (7). Remove lock ring (8) by inserting lock ring tire iron (c), curved side up, into prying notch (d) on lock ring (8) and gutter of rim (b) . Pry lock ring (8) out enough to insert flat tire iron (e), adjacent to tire iron (c), between lock ring (8) and base of rim (b). Work both tire irons (c and e) progressively around rim (b) until lock ring (8) is completely removed. With lock ring (8) removed, hold aligning ring (7) down to remove and discard O-ring (9) from rim (b) . If aligning ring (7) becomes cocked on rim (b), its removal will be difficult. i. Slide aligning ring (7) off rim (b) by lifting flange of aligning ring (7) straight up. 13-6