Analyze the risks of over-expanding a spiral retaining ring during manual installation with pliers.

Manual installation of spiral rings (especially the 'light duty' series) without a proper tapered mandrel often leads to 'over-expansion'. If the ring is opened wider than necessary to clear the shaft diameter, the outer fibers reach the plastic deformation zone. This results in 'permanent set', where the ring's free diameter $D_f$ increases. Consequently, the ring will not seat tightly in the groove bottom, leading to a 'loose' assembly. A loose ring can vibrate, causing 'fretting' of the groove, and will have a significantly lower RPM limit because it is already 'pre-expanded' toward the lift-off point.