A car uses 100–150 bearings, and the hub bearing directly affects driving safety. This article traces the evolution from Gen-1 compact bearings to Gen-3 units integrating flange, ABS sensing and steering knuckle, and the new demands of electric vehicles: insulated-coating and hybrid ceramic bearings against electrical erosion. Sealing performance, preload control, low-friction design for energy saving and NVH control are the key quality dimensions of modern hub units.