@wbs
I stand corrected! The SME website for the Model 30 series two states 60 rubber rings, plus one to counteract the pull of the drive belt, plus two spares! Of note is the fact that these rings are clearly visible. Rubber is an elastomer with some self-damping, but additional damping was built into the suspension towers. The designer aimed for critical damping, so if the deck was pushed down and then released, it would return to the equilibrium position with no overshoot.