Ball bearings are the most common type of wheel bearings used today (along with roller bearings—though the latter don’t have the versatility of the ball ones). Other types include tapered roller bearings, mainly used for trucks, and precision ball bearings, designed for intense radial loads. Regardless of the type your vehicle has, the warning signs are the same, specifically a bad wheel bearing sound.
Here are just a few things to keep in mind:
First and foremost, listen! The most common and most easily identifiable symptom of a bad wheel bearing is an audible one. If you notice a grinding or grating noise coming from your wheel or tire, take note that this is very likely caused by a bad wheel bearing—especially if the noise gets louder as the vehicle accelerates.
Another revealing sign of bad wheel bearings: A car that feels loose as you drive it. Looseness can be difficult to convey, but basically, it refers to steering your car and finding that it seems less responsive or less precise than usual. Loose steering is not always due to a problem with the wheel bearings, but it very often can be. Sometimes the wheel bearings can become worn down, which causes them to loosen within your wheel assembly.
A related phenomenon is pulling. When you drive, does the car go where you tell it to or does it seem like it has a mind of its own, veering in a particular direction? Again, this is not always because of a problem with the wheel bearing, but that can certainly be a culprit.
Finally, pay attention to your tires. Rotating your tires regularly can help prevent wear—but if you find that you have extremely uneven wear, you may want to have the wheel bearings looked at.