My Posts: All Forum Topic
It's one of 2 things. Either the shaft is too loose in the bearing, in which case a bit of loctite will do the trick. OR, the bearing is loose in the frames. For this you can wither tighten the frames or as I have done on older frames, put a thin bead of epoxy round the bearing before putting the frames together. One of the problems with plastic frames is that in time, plastic creeps and changes shape a little.
Also check that it is the shaft rocking and not the hub. The plastic hubs can sometimes be a bit of a loose fit - a touch of loctite will firm it up - leave it to cure overnight etc etc.