As a natural evolution of the roller and taper bearing, and the press-in sealed bearing, the wheel bearing and hub assembly features a flange, a press in sealed wheel bearing, and the wheel hub all as a single unit. This makes changing a bad wheel bearing a much easier job. When you have a bad wheel bearing, you will hear a groaning sound on the unloaded wheel (the one that faces the direction you are turning). Generally expect to get 50-100k miles out of this part.