How does 'Spinning' of the retained part lead to the failure of a spiral retaining ring?

If the part being retained (e.g., a bearing race) spins relative to the retaining ring, it can cause 'frictional winding' or 'unwinding'. For a spiral ring, if the direction of rotation matches the direction of the spiral's coils, the friction can cause the ring to contract or expand, potentially pulling it out of the groove. This is known as the 'Capstan Effect'. Furthermore, the friction generates heat, which can soften the ring material and lead to premature wear. To prevent this, the retained part should be keyed or press-fitted to prevent rotation, or a 'multi-turn' ring with a high 'cling' force should be used to increase the torque required to move the ring.