How can a pothole strike in December cause a bearing noise in January? In this video, we cover how a pothole damages the races of a bearing and how the driving increase the size of the damaged area.
When the damage happens the damage causes turbulence. The turbulence in the grease increases temperatures of the grease. Burned or oxidized lubricant may leave a dark coating on bearing surfaces. If a bearing overheats, the hot lubricant breaks down and can cause scoring and even etching of the bearing surfaces.
Also, water and other corrosive elements can create this condition, which leads to spalling in a few months.