The ABEC standard is used to classify bearings according to their machining tolerance. This standard is regularly called into question because it does not include certain technologies that are important for guaranteeing proper operation, both in terms of efficiency and bearing life.123Roulement therefore makes little use of this standard.

Simply stated, wheel bearings allow cars and trucks to run smoother and more efficiently by reducing friction and supporting vehicle weight. When they start to fail, you can usually tell.

Some bearings are available with more or less important variants (high or low internal clearance, special grease, very high temperature, etc.). These variants are systematically indicated by prefixes and suffixes in the part number.For example, the suffix "2RS" means that the bearing is splash-proof, thanks to a sealing flange on both sides of the bearing.The suffix "C3" means that the bearing has increased internal clearance, and will require a higher operating temperature, or a higher rotation speed.

You’ll hear clicking, cracking, grinding, snapping, or whining noises coming from your wheels or tires. They’ll increase when accelerating or turning.

But sealed wheel bearings are non-serviceable and should never be repaired, only replaced. Even if a pro suggests repairing a bearing, don’t let them. Trying to reuse a damaged wheel bearing can result in an accident and severe injury.

Depending on the vehicle, you can save hundreds in labor replacing wheel bearings yourself. Most auto parts stores will lend you the specialty tools and equipment needed to replace a wheel bearing.

NOTE: Whether you DIY or your mechanic replaces the bearing, always install a new axle hub nut. Most hub nuts are prevailing torque fasteners, used on critical components (like securing axle shafts to hub bearings) where a loose nut could lead to disastrous consequences.

Read on to learn the most common bad wheel bearing symptoms, based on my experience (50 years in the industry) and that of Joe Simes, a National Institute for Automotive Service Excellence (ASE) certified and Toyota master technician. But first, a little background.

Absolutely not. It’s crucial to get bad wheel bearings diagnosed and replaced ASAP. If not, you could lose a wheel or get in an accident.

Unlike unbalanced tires, shaking caused by a bad wheel bearing should be obvious from the side of the car where the bearing is failing.

A stainless steel bearing is generally magnetizable, as it is made from AISI 420 stainless steel, which is harder and more shock-resistant than standard stainless steel (AISI 304).To check whether your bearing is made of stainless steel, simply read the reference engraved on the side of the bearing. This reference should begin with the prefix "S" meaning "Stainless Steel".

On many vehicles, the ABS sensor is built into the wheel bearing, or it’s externally mounted adjacent to the spinning part of the bearing where the sensor measures vehicle speed. Damaged from a wobbly wheel bearing, the sensor will send erratic readings to the vehicle’s computer, illuminating the ABS light.

Friction from a failing wheel bearing produces heat. After driving, without touching the tires or wheels, carefully walk around your vehicle and use a non-touch thermometer to measure if one is hotter than the others.

These suffixes mean "with 1 or 2 rubber seals". At 123Roulement, we use the number "2" to specify when the bearing is sealed on both sides.

The Deep Groove Ball Bearing, known as 6812-2RS-SKF SKF, has an inner diameter of 60 mm, an outer diameter of 78 mm and a thickness of 10 mm.

The average cost to replace a sealed wheel hub bearing is $350 per wheel. However, depending on the make and model, shop labor rate, the cost of the bearing itself and any additional damage, the total could exceed $1,000.

This suffix indicates that the bearing is designed for very high operating temperatures. In general, the temperature is indicated after this suffix.Beware, these bearings are not suitable for all applications, and will require a high temperature for optimum service life.

A bad wheel bearing can cause a tire/wheel to move or glide unevenly or sluggishly. It can also cause your brakes to drag, pulling your vehicle to one side when you try to stop.

According to Simes, a failing wheel bearing will likely produce a soft, faint vibration that’s felt before it’s heard. There may also be a vague rhythmic humming or droning sound that increases over time and with speed.

You can service or replace tapered wheel bearings yourself. Never reuse any wheel bearing that’s loose, worn, noisy or shows any signs of wear.

On modern front- and four-wheel drive cars, wheel bearings are a set of permanently sealed, precisely machined steel ball or straight roller bearings. The balls, or rollers, are encased in a “cage” that supports the bearings, allowing them to rotate freely.

The cage and rollers are held together inside a hardened metal ring called a “race.” The seal keeps grease in and damaging water and debris out. Wheel bearings are installed inside, and secured to, the suspension, either by press fit, bolts or a snap-ring. Once mounted, the wheel bearing rides on the axle shaft, allowing the tire/wheel to spin effortlessly.

The Deep Groove Ball Bearing, known as 6812-2RS-SKF SKF, has an inner diameter of 60 mm, an outer diameter of 78 mm and a thickness of 10 mm.

Joe Simes is an ASE and Toyota master technician. After 20 years in the industry, Simes recently became a Pennsylvania Department of Education certified automotive technology instructor at North Montco Technical Career Center in Lansdale, Pennsylvania.

These suffixes mean "with 1 or 2 sheet metal deflectors", for dust-tightness. At 123Roulement, we specify whether the bearing is sealed on 2 sides with "ZZ".

Means "increased internal clearance". Often referred to as high-speed, this means that the bearing is designed for high rotational speeds and moderately high temperatures. CAUTION: a bearing with increased internal clearance will not operate optimally at low speeds. Please refer to the data sheet for the bearing you are looking for to find out its rotation speed limit.

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These suffixes indicate that the cage (the part of the bearing that holds the balls apart) is made of polymer material. Usually made of glass-fiber-reinforced polyamide.

The Deep Groove Ball Bearing, known as 6812-2RS-SKF SKF, has an inner diameter of 60 mm, an outer diameter of 78 mm and a thickness of 10 mm.