Amongst the most critical aspects affecting the life of a conveyor idler, are the design, manufacture and assembly of the sealing system. If the design is such that the seal effectively prevents the ingress of contaminants into the bearing, but increases frictional resistance of the roll, then increased wear on the tube will result in premature shell failure. On the other hand, utilising a seal, which limits frictional resistance to a minimum, but does not adequately protect the bearing, will result in contamination, and eventually premature bearing failure.