Compared to even the finest steel bearing balls, ceramic balls have several remarkable advantages that justify their higher cost. They’re significantly lighter and lower in friction, so they accelerate faster and roll further at a higher speed, even with little or no lubricant. They’re so hard and strong that they crush dirt, debris, and even rust, which keeps the steel raceways clean and polished. Furthermore, they dissipate heat better, so bearings (and wheels) run cooler. They’re also rustproof, so they last longer even when ridden in wet conditions.