What is a ball bearing fan ?
For ball bearing fans, there are several miniature steel balls surrounding the cylinder. When the fan rotates, the balls rotate too. Compared to sleeve bearing, it is point friction and has less friction. There are no oil leakage problems so its lifespan is longer, generally 40K to 50K hours for two ball bearing fans and 30K to 40K for 1 ball / 1 sleeve fan (C).