Wheel Bearing Buyer's Guide
- A wheel bearing is a metal ring, also known as a race, that houses a set of steel balls or rollers.
- There are two wheel bearings in on a single wheel hub assembly and those are the inner and outer bearings.
- The wheel bearing types are ball, roller, precision ball, and tapered roller bearings.
- The symptoms of a worn-out wheel bearing include unusual noises, loose wheel, vibration on the steering wheel, uneven tire wear, and premature wearing of the brake rotor and pad.
- Aftermarket wheel bearing replacements on CarParts.com cost around $3 to $300.
No matter how powerful a car engine is, one can’t overlook a good reliable wheel bearing. For your wheel to spin smoothly, meaning not being affected by too much friction, it needs to have a bearing—be it a ball or a roller. The balls or rollers inside lessen the amount of friction as the wheel spins.
The wheel bearings constantly work as you drive your car. It spins thousands, even millions, of times as you drive for miles. Due to it being in constant motion, wheel bearings deteriorate over time, whether because of natural wear or contamination of external elements. It is important to make sure they are in good condition to ensure a smooth and safe ride. If you’re having issues with your wheel bearings, here are the important facts you need to know.
What is a wheel bearing?
A wheel bearing is a metal ring, also known as race, that houses a set of steel balls or rollers. This component allows the wheel to spin as fast as it can by reducing friction. It is a part of the wheel hub assembly that’s mounted on the axle shaft. There are two wheel bearings in a single wheel hub assembly and those are the inner and outer bearings.
Front-wheel bearings and rear wheel bearings could hold up to 850 lbs depending on the front-to-rear weight distribution of a car. In a 6-ton SUV, each bearing can carry about 1,500 lbs.
Types of wheel bearings
There are two main types of wheel bearings, with each one having its own variation. Here are their differences.
Considered as the most common type, the ball bearing is famous for its versatility. This bearing can absorb both the weight given to the wheel (radial load) and the cornering pressure experienced by the wheel (thrust or axial load). It sees use in various wheeled transportation and objects, such as bicycles, skateboards, and roller skates.
Precision Ball Bearings
The precision type is a more advanced version of the ball bearings tailored for high-pressure and high-performance applications. It can withstand heavier radial and thrust loads. Apart from that, the precision ball bearing is better in reducing friction, has a higher rotation speed, and boasts of higher resistance to heat. They get used in more demanding applications such as racing cars and aircraft wheels.
The roller bearing is another basic form of wheel bearings. Roller bearings don’t have the same versatility that ball bearings have basically because rollers don’t handle axial loads well. Unlike ball bearings that have actual metal balls, rollers have metal cylinders enclosed by the inner and outer races. So roller bearings only see use in non-cornering wheels, such as hand trucks.
Tapered Roller Bearings
This roller bearing features a cone-shaped assembly that orients the rollers to a certain angle. It reduces the friction at greater axial loads, which usually happens when the car is cornering. When you corner, the wheels tilt to varying angles depending on the gross vehicle weight. Tapered roller bearings keep the shifting parts from grinding when the wheel angles. Tapered bearings usually come in pairs, which get put together either face-to-face or back-to-back.
How does a wheel bearing fail?
If wrongly adjusted, a wheel bearing may wear out early. The sealed grease, which is the most vulnerable part of the bearing, will start to leak. Dirt enters the bearing cavity, damaging the wheel bearing.
Another factor that contributes to wheel bearing damage is water. This causes rusting of the bearing and contaminates the grease in the bearing cavity. Some bearing seals are not built to keep water out of these bearings. Vehicles, most especially off-roaders (with wheels frequently sunk in the mud or hub-deep water during floods), must have their bearings cleaned thoroughly. In this manner, there will be a greater interval before the wheel bearings are replaced.
Symptoms of a bad wheel bearing
As for the rule of thumb, wheel bearings can last up to 100,000 miles. Affecting factors such as driving habits, operating conditions, and the overall quality determine the actual lifespan of the bearing. Some bearings fail short of the minimum indicated life which is 85,000 miles, while some bearings last longer than 100,000 miles. Here are the common bad wheel bearing symptoms.
Unusual noise coming from the wheel area
Unlike most components in your vehicle, there is a tiny window of time to notice the symptoms of a failing wheel bearing. It’s often too late to perform the right countermeasures. That’s because when bearings wear, they can break in an instant. If you’re lucky, you’ll catch weird noises coming from the wheel area. This should signal a failing wheel bearing. If you hear a grinding noise, chances are one of your bearings has run out of lubrication. Without enough lubrication, the metal balls or rollers would grind against the inner surface of the outer race.
Other wheel bearing noises that show a problem include:
- Roaring or humming
- Clicking or popping
A worn-out wheel bearing may sometimes cause the wheel to have an abnormal play. This could stem from damaged steel balls or rollers that came loose from the assembly. To check if you have a loose wheel due to a worn-out bearing, jack up your car (or use a lift if you have one at your disposal) and wiggle the wheels with two hands. Any movement of the wheel from the axle shaft is a “play.” A wheel hub with a healthy bearing would most likely hold the wheel as tight as possible, negating any looseness or play.
Vibration on the steering wheel
If your wheel became loose because of a failing wheel bearing, you could end up feeling a vibration on the steering wheel when your car is moving. Although a vibrating steering wheel could originate from other issues aside from the bearings, you can distinguish its cause by the speed of your vehicle. Shaking at high speeds often comes from improper tire balance, while wheel bearing issues causes the wheel to vibrate even at low speeds.
Uneven wearing of brake pad or rotor
A bearing that’s in bad shape causes not only the wheel to become loose but it also causes the brake rotor to experience a runout. A rotor runout happens when the rotor tilts or deviates from its standard axial plane. This could cause the rotor to warp or the brake pads to wear out faster than usual. The brake components on the affected side would end up failing faster than the ones on the other side.
Uneven tire wear
Since the affected tire often gets loose, it can wobble as you drive. This causes the tire on the affected side to wear out faster. As a result, you or your technician will notice signs of uneven tire wear during a wheel inspection.
Other factors to consider when buying a replacement wheel bearing
Aside from the type of wheel bearings you may need, there are also other factors that you have to consider when buying a replacement wheel bearing. Below are a couple of things you’ll need to remember when shopping for new wheel bearings:
Ceramic vs. stainless steel wheel bearings
Most wheel bearings are made of stainless steel because this material doesn't rust and has the ability to resist corrosive elements. They can work well even when subjected to high temperatures and yes, they can do that without showing signs of corrosion and degradation and without a need for lubrication.
Ceramic wheel bearings, on the other hand, are made from silicon nitride, which can lubricate itself. They are a great investment because they definitely last longer than steel bearings. Ceramic bearings are also stiffer, keeping your wheels pointed and able to spin and accelerate faster for better performance. Not only do they lessen rolling resistance, but ceramic bearings also ensure lower friction, making the battery last longer and the engine run cooler. With these bearings, the driveline also becomes more efficient.
Wheel bearing kit vs. individual wheel bearing
Those who need to replace only one bearing can save bucks by getting a unit that's sold individually. But if you need several bearings plus other parts necessary for easy installation, a wheel bearing kit is right for you. A kit may include some or all of these things: bearing protector, bearing cover, split pin, seal, lock nut, circlip, o-ring, washer, and spacer.
How much is an aftermarket wheel bearing replacement?
When purchasing an aftermarket wheel bearing replacement, it is wise to base your choice on the type and specifications of the bearing that needs replacement. This will help you avoid incompatibility issues, which can lead to more serious vehicle problems. You also need to consider other important factors, such as materials and the quantity they are sold.
Aftermarket wheel bearing replacements could cost you from $3 up to $300. This largely depends on the compatibility and quantity. You can purchase aftermarket parts individually or in sets. However, keep in mind that when dealing with a failing wheel bearing, you need to replace both sides.
CarParts.com has a wide range of durable, aftermarket replacement wheel bearings. To find the right fit, indicate your vehicle’s year, make, and model in the filter tab. If you are running on custom wheels, remember to review the product details first before proceeding to checkout.
10 DIY Steps on Replacing your Car's Wheel Bearing
A typical wheel bearing can last for an average of 100,000 miles, but eventually, the stresses of the road will cause them to wear out. And since bad bearings can lead to groaning wheels or ? in a worst-case scenario? the wheels falling off, they must be replaced immediately as soon as they show signs of wear or damage.
Difficulty level: Moderate
- Jack and jack stands
- Seal and race driver set
Step 1: With the car parked on a level surface, jack up the car and place the jack stands under the frame for support.
Step 2: Remove the wheel and the brake caliper from the wheel hub. Clean the inside of the hub and spindle with rags.
Step 3: With your screwdriver, gently pry the grease cup out from the hub. You can use the mallet to help loosen the cup.
Step 4: Remove the cotter pin, retaining ring, and axle spindle nut. Next, grab the disc and take out the hub or rotor-hub assembly from the axle. At this point, the outer wheel bearing should drop out.
Step 5: Knock the outer race out from the hub with a drift and hammer. Tap alternately on each side to prevent cracking the race. Once the outer race is removed, flip over the hub and use the same procedure to knock out the inner race, bearing, and seal.
Step 6: Pack the replacement inner and outer wheel bearings. Make sure that the grease goes inside the cage and rollers.
Step 7: Using an amply-sized driver, drive in the inner race until it is seated all the way in. Put the bearing in the race, pack it in with grease, and use the driver again to seat the grease seal. Flip over the hub and repeat the process for the outer race. Make sure that all the races and seals are level.
Step 8: Fill the hub with just enough grease and place it on the spindle. Attach the wheel bearing, washer, and axle nut.
Step 9: Replace the retaining ring and secure it with a new cotter pin. Replace the bearing grease cup and clean all the excess grease from outside of the hub.
Step 10: Re-install the calipers and wheel back into the hub and check for wheel play. If done correctly, the wheel should have little or no play when moved.