Bad wheel bearings can indeed affect overall ride quality and cause a vehicle to ride rough. Wheel bearings, which are very similar in size and shape to BB gun pellets, are located deep inside a vehicle's hub, which is the long spindle-like projection that each vehicle tire rides on. When wheel bearings go bad, they become pitted and their edges become roughened. This negatively impacts the spinning motion of the inner hub assembly, and as a result, affects the spinning motion of each vehicle tire, which adversely impacts vehicle ride quality.
Wheel bearings, in addition to facilitating smooth, low-friction movement of a vehicle's hub assembly and tires, help to ensure the stability of each individual car tire. As a hub spins in relation to tire speed, wheel bearings serve to reinforce and guide the spinning hub assembly. Bad, worn-out wheel bearings lose their structural soundness and allow the spinning hub to develop play, or excessive movement as it spins. This movement gets translated to the spinning car tire, which is anchored to the hub assembly by way of the tire lug nuts. This excessive tire and hub movement adversely affects a car's ride. It destabilizes the tire/hub assembly and allows excessive movement, which can translate into a loose, vibrating, or rough ride as a car is driven.
As wheel bearings go bad, they lose their ability to effectively spin against the rotating tire/hub assembly. This translates into increased friction and vibration that gets transferred from the spinning hub assembly to the car tire, a condition that can normally be felt, at least partially, by the car driver in the form of a shaky, vibrating steering column. This increased friction and vibration translates into a rough vehicle ride. Generally, the faster a vehicle is driven, the more pronounced this becomes. A car with bad wheel bearings driven at highway speeds can be very noisy and, in extreme cases, difficult to control and/or maneuver.
