What Is a Bad Wheel Bearing?

It may start with a slight grinding sound. If you have a front wheel drive car, the sound will usually seem like its coming from one of front tires and it may get louder when you turn corners. The problem? Quite often it’s a failed wheel bearing.

Great, but what exactly is a wheel bearing? And why do they cost so much to fix? In this article, we will tell you what a wheel bearing is, where it's located, how it got damaged and why it seems so expensive to fix them.

What Is a Wheel Bearing?

Let’s start by exploring what a bearing is. A bearing is a component that makes a shaft spin with minimal friction. Picture any spinning wheel or gear and there likely is bearing at the center of it. The best bearings are ball bearings or tapered bearings. They are made up of a set of steel balls (or small cylinders) that ride on the inner surface or “race.” They are used on all kinds of vehicles, from bicycles to aircraft and cars.

A ball bearing – 

Cars use tapered bearings

The wheels on a car spin freely because they are mounted on tapered bearings. Tapered bearings are like ball bearings but have small metal cylinders that ride on the race instead of balls. Tapered bearings are mounted inside the wheel hub which is a hollow chunk of cast iron at the center of the wheel. The hub holds the lug bolts that you use to bolt the tire onto the wheel.

Inside this wheel hub is a tapered wheel bearing 

Why do wheel bearings fail?

When a wheel bearing is new, it has rubber seals that keep dirt and grit out of the rotating parts. The problem is when the rubber degrades and cracks over time, eventually dirt and grit get inside the bearing. When this happens, the tapered rollers and the race they ride on will become damaged and start making noise. Initially, the noise starts out very faint but slowly it becomes louder over time. It often sounds like the noise that your tires make when hitting a rumble strip on the highway, just not nearly as loud. According to our subject matter experts, Foss Motors of Exeter, a local Chrysler, Dodge, Jeep, Ram dealership in Exeter, NH, wheel bearings do not fail immediately so don’t panic. They usually give you some time before you need to have them replaced.

What side is the bad bearing on?

You have wheel bearings on both sides of the front of your car. Generally, though, only one fails at a time but it’s a bit of a trick to find out which side has failed. To determine the side the failed bear is on, mechanics will usually drive down the road and sway the car slowly from side to side. They take notice whether the noise gets louder or softer as the car sways. If the noise is a little less if you turn right, the damaged bearing may be on the left, or vice versa.

Replacing Wheel Bearings

Replacing a wheel bearing is usually a bit expensive because of all the labor involved. There are a lot of parts to remove and get out of the way before you can get to the wheel bearing. Replacing wheel bearings is not recommended as a DIY project because hydraulic presses are generally needed to get the old bearing out and press the new one in.  This is one repair to leave to the professionals.