Ball bearings produce less noise than roller bearings, and bearings with relatively less sliding produce less (friction) noise than bearings with relatively more sliding. Bearings with more balls and thicker outer rings also produce less noise. 2. Bearings using solid cages produce less noise than bearings using stamped cages. 3. Bearings using plastic cages produce less noise than bearings using both cages. 4. High-precision bearings, especially those with higher-precision rolling elements, produce less noise than low-precision bearings. 5. Small bearings produce less noise than large bearings.