Sliding closet door rollers

Part has D-179 Stamped on side. Rollers look to be plastic and are no longer round. I have 3 mirrored sliding closet doors on 2 tracks. Doors lift up to be pulled out. rollers on bottom. 2 rollers on each door I was able to remove roller assembly from its casing which is held in on bottom of door frame. I need to replace rollers so door will glide easier.

Metal on closets is not a good plan. At the very least, replace them the instant you feel any drag.