Spindle lubrication in a roulette wheel ensures smooth, consistent rotation by reducing friction and wear on the central spindle. Proper lubrication allows the wheel to spin at a uniform speed, preserving randomness by preventing irregularities that might impact the ball's movement or outcome. If lubrication is insufficient or uneven, the wheel may develop slight biases or inconsistencies in spin speed, potentially affecting fairness and predictability. Regular lubrication maintenance is crucial to maintain the integrity and reliability of the wheel over time.