Everything you ever wanted to know about wheel bearings and the noises they make
One of the more common complaints people bring to mechanics is that “my car’s making a funny noise”.
And while cars are complex machines that can emit strange noises from all manner of places and for a number of reasons, wheel bearings are components that tend to make a noise when they are defective.
This guide will talk you through what a bad wheel bearing sounds like, and what you need to do about it.
What Is a Wheel Bearing?
Your car’s wheels spin around a stationary axle, and in order for them to do so, something has to allow for “slip” between the two. That something is a wheel bearing.
A vehicle’s wheel bolts to a hub, and the wheel bearing (there may be an inner and an outer) is in the center of that hub.
Wheel bearings vary in size and come in many different styles, but a common trait is that they use either small balls or cylindrical rollers that roll between two smooth metal rings: one on the outside that fits into the hub, the other on the inside that fits around the axle. In some cases, the bearing assembly also has side plates that seal the necessary grease inside.
A wheel bearing leads a tough life. The balls or rollers inside them can be about the size of the diameter of a pencil or AA battery, and there might be a 12-20 or so around the circumference of the bearing.
Each bearing (or pair of bearings) at each wheel has to support the entire weight of that corner of the car. Furthermore, the wheel turns quickly at high road speeds, making for a lot of potential wear inside the bearing.
Although it’s not uncommon for wheel bearings to last up to 100,000 miles, they eventually go bad. “Natural causes” would include normal wear on the balls or rollers, or grease eventually leaking out through the seals that hastens wear.
The life of a wheel bearing also can be shortened by sharp blows, such as the wheel hitting a pothole, as well as water seeping past the seals and diluting the grease or by sand or salt that likewise finds its way past the seals and causes premature wear.
How long does a wheel bearing last?
Wheel bearings have an average lifespan of 136,000 to 160,000 km (approximately 85,000 to 100,000 miles). This is only a rule of thumb though, the actual lifespan of a wheel bearing depends on the quality of the wheel bearing and the operating conditions.
Signs A Wheel Bearing is Going Out
What are the signs of a bad wheel bearing? Here are six critical signs indicating your wheel bearing may be defective:
- Steering Wheel Vibrations: Besides a loose steering wheel, vibration can also indicate a bad wheel bearing. Over time, a bad wheel bearing will intensify bearing play on your wheels, especially when making turns or driving at high speeds.
- Unusual Noises: What does a bad wheel bearing sound like? If you notice a grinding or grating noise from your wheel or tire, you might have a bad wheel bearing—especially if the noise gets louder as the vehicle accelerates.
- Loose Steering: Looseness can be difficult to convey, but in this case, it refers to steering your car and noticing it to be less responsive or precise than usual.
- Uneven Tire Wear: When a wheel bearing wears down, the effects will likely extend to your tires. Rotating your tires regularly can prevent wear, but if you have extremely uneven wear, inspect the wheel bearings.
- Brake Issues: If your bearings are weak, you might notice inefficient braking or brake slips as you drive. When bearings become loose, the rotors push the piston further when you tap on the brakes, making them feel weak.
- ABS Light: If your brakes or tires receive excessive pressure because of loose wheel bearings, this can cause the ABS light to illuminate. While an ABS light may not always indicate a loose bearing, a simple code check can help identify the culprit.
How to Identify a Bad Wheel Bearing Noise
Here are common noises that suggest bad wheel bearings:
- Humming: A humming noise while driving can be caused by several issues, but a wheel bearing or CV joint is one of the more likely (and problematic) issues.
- Squealing & Growling: The classic sounds of a bad wheel bearing are cyclic chirping, squealing, and growling noises. You can verify the sound is related to wheel bearings if it changes in proportion to vehicle speed.
- Howling: Howling that solely occurs during deceleration indicates loose pinion-bearing preload. If howling happens under acceleration at different speeds, then it’s probably worn-out gears. However, worn-out bearings also make a howling noise when they don’t support the gears correctly.
What Causes Noise From Wheel Bearings?
Wheel bearings are attached to your wheels and are always in motion when you’re driving.
Since your wheels’ tires are constantly in contact with the road, there are a number of things that can cause wheel bearings to make unusual noises or become damaged. Here are the most common.
#1. Normal Wear and Tear.
Over time, wheel bearings naturally wear down from regular use. As your car accumulates miles, the constant motion and stress on the bearings will cause them to slowly deteriorate.
This is a normal part of vehicle aging, but you’ll want to address worn bearings fairly quickly to prevent further damage to the bearings and surrounding components.
#2. Driving on Rough Roads.
Because wheel bearings support the full weight of a vehicle, bumpy roads, potholes, and curbs can be especially hard on the bearings.
When you hit these obstacles, it can damage the small balls inside the bearing or the ring they sit in. This damage creates tiny flaws that lead to more heat and friction as you drive. Over the course of weeks or months, this can cause the bearing to fail and make noise.
#3. Improper Installation.
If your wheel bearings were recently replaced and you’re hearing noises, the problem might be a bad install. When bearings aren’t installed correctly or according to the manufacturer’s guidelines, they can become damaged quickly.
While replacing your own wheel bearings is definitely possible, this is one task that’s best left to the professionals in most cases. Specialized tools are often necessary and installing them incorrectly can lead to serious safety issues.
#4. Driving Through Deep Water.
Wheel bearing seals are designed to keep lubricant in and contaminants out. However, repeated or long exposure to deep water can eventually compromise these seals.
If you often drive through flooded streets or deep puddles, water might eventually work its way into the bearing. When this happens, it can mix with the lubricant, making it less effective. This can lead to increased friction and potential damage to the bearing.
Modern wheel bearings are better at resisting water entry than older designs, but they’re not completely waterproof. If water does get in, you can’t simply clean and re-lubricate a modern sealed bearing. In most cases, a water-damaged bearing will need to be replaced entirely.
To protect your wheel bearings (and other components susceptible to water damage), avoid driving through deep water unless you absolutely have no choice.
#5. Unbalanced Tires or Worn Suspension.
Your wheel system includes many parts working together, including the bearing, tire, suspension components, and more.
If your tires are unbalanced or your shocks are worn out, it can put extra stress on your wheel bearings. This added strain can cause the bearings to wear faster and make noise.
#6. Accident Damage Near the Wheel Area.
If your car has been in an accident and a wheel area is affected, it could have damaged the wheel bearings. Even if the damage isn’t immediately obvious, the impact can cause internal issues with the bearing. This damage might lead to noise and eventual bearing failure.
#7. Manufacturing Defects.
While rare, sometimes wheel bearings can have defects from the factory. These flaws might not be apparent at first, but they can cause the bearing to wear out faster than normal or produce noise earlier than expected.
If you’re experiencing bearing problems in a relatively new vehicle, this could be the cause.
How to Diagnose Damaged or Noisy Wheel Bearings
To check for a damaged wheel bearing:
- Use a floor jack to lift the vehicle until the tire is off the ground.
- Try to move the tire up and down, then side to side.
- If the wheel wobbles or has some free play, the bearing might be damaged.
We made this video to demonstrate how to perform this inspection of the wheel bearing. Remember, the noise from a bad wheel bearing can vary. How loud or noticeable it is often depends on how severely the bearing is damaged.
How Much Does Wheel Bearing Replacement Cost?
On average, replacing a wheel bearing costs between $250 and $600 per wheel, including parts and labor.
However, depending on the make and model, the shop labor rate ($47 to $215 per hour, according to AAA) and any additional damage could push the cost beyond $1,000 per wheel.
However, on some vehicles, it can be less than $100 per wheel. And you can save hundreds in labor if you DIY. If you don’t have the tools, most auto parts stores will lend you the specialty tools and equipment needed.
NOTE: Whether you DIY or your mechanic replaces the bearing, always install a new axle hub nut. Most hub nuts are prevailing torque fasteners. They’re used on critical components, like securing axle shafts to hub bearings, where a loose nut could lead to disastrous consequences.
Can You Continue Driving If You Suspect a Bad Wheel Bearing?
If you suspect a bad wheel bearing, it’s always best to address the issue quickly rather than continuing to drive. But if you absolutely need to drive, keep to lower speed roads and avoid long trips or highways. Pay close attention to any changes in noise or vibration, and be prepared to stop if the symptoms worsen.
While a slightly worn bearing might not pose an immediate danger, the problem can quickly worsen, leading to potentially hazardous situations. A severely damaged wheel bearing can cause the wheel to seize or even separate from the vehicle, resulting in a loss of control.
On top of that, driving long enough with a bad bearing can cause damage to other parts of your vehicle, such as the hub, CV joint, or axle. This can turn a relatively simple and affordable repair into a much more expensive one.