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ASK MATT Q&A

BCA’s “Ask Matt” feature answers the common wheel hub and bearing questions that we get from technicians and DIYers.

INSIGHTS FROM AN INDUSTRY EXPERT

Matt-Gorski_200_R

ABOUT MATT

Matt Gorski is NTN's Manager of Product Development for the Automotive Aftermarket.

Matt is a car guy who spends his free time wrenching on cars, and can often be found under the hood of a vehicle belonging to a friend, neighbor, or co-worker. He is the go to guy when you have a service indicator light on, or hear your car making a weird noise.

Matt started out in the automotive industry as an auto technician. He worked as an auto tech for 12 years before joining the automotive aftermarket as a technical trainer, and then moved into product management.

Matt’s experience in the automotive aftermarket and as a technician makes him a great resource for end-users, technicians and countermen alike.

ASK MATT Q&A - INSIGHTS FROM AN INDUSTRY EXPERT

Topic: Tesla Model S & Model X Wheel Bearing Replacement 

QUESTION: I am installing a BCA WE61960 on the front of a single-motor, RWD Tesla Model S. It has an open center and splines to fit a dual-motor, AWD Model S. Is this the correct bearing for the application?

ANSWER: Yes. The BCA WE61960 is the correct bearing for both the single- and dual-motor Model S in the front and rear. The splined center opening in the hub does not impact the hubs function or performance in any way when installed on the front of the RWD, single motor models. The bearing preload is set at the factory using orbital forming. This cold process rolls the lip of the inner race to permanently set the specified preload on the hub bearing. There is no need for an axle nut to set the preload when there is no CV axle.

Topic: Tesla Model S & Model X Wheel Bearing Replacement 

QUESTION: Is it necessary to disconnect the high voltage battery to service the wheel bearings?

ANSWER: No. The highest voltage you will come in contact with is 12 volts of direct current from the wheel speed sensor. Just make sure the car is in tow mode. There is not any need to disconnect the 12-volt or high voltage batteries.

Topic: Hybrid and EV Wheel Bearings 

Tesla Model SQUESTION: We know that Hybrid Electric Vehicles (HEVs), Plug-In Hybrid Vehicles (PHVs), and Electric Vehicles (EVs) are heavier than comparable gasoline powered vehicles. Can this have any effect on the lifetime and performance of the wheel bearings?

ANSWER: Absolutely, the service life of a wheel bearing in one of these vehicles could be shorter. The added curb weight needs to be supported by the suspension and chassis, and this can take a toll over time. The bearings could be more susceptible to damage from an impact, whether it’s a curb strike or a nasty pothole.

Topic: Hybrid and EV Wheel Bearings

EV Wheel Hub Assembly for Tesla Model SQUESTION: Is there a fundamental difference between the wheel bearings on a BEV or EV versus a comparable gasoline-powered vehicle, or are they nearly the same?

ANSWER: No, in most cases they’re the exact same. Some OEMs have experimented with adding rows of ball bearings to help carry the added weight, but it’s not common.

Topic: Tapered Roller Bearings

QUESTION: What is the terminology for the two parts that make up a tapered roller bearing set?

ANSWER: Tapered Roller Bearings are generally packaged as a two-piece, matched set.

The inner bearing assembly contains the rollers, bearing cage and inner race, and is referred to as the cone, or more commonly just called the bearing.

The outer ring of the bearing set is referred to as cup, outer race, or commonly just the race. The race is a single piece with no moving parts.

When used as a set, the bearing will seat inside of the race, which sandwiches the rolling elements and cage between the inner and outer race.

Topic: Tapered Roller Bearings

Tapered Roller Bearing SetQUESTION: Tapered bearings have been in use for decades, but they’ve fallen out of use in common applications in favor of bearing styles which are more economical for OEMs. So, do tapered wheel bearings have anything to offer over other types of bearings?

ANSWER: Absolutely, tapered bearings are designed for high axial, radial and combined load capacities. They can cope with heavier loads thanks to the large contact area between the rollers and the rings. They’re not very costly to manufacture, and they’re extremely well suited for commercial vehicles as well as medium to heavy duty trucks.

Topic: Tapered Roller Bearings

"Hand-Packing" a Tapered Roller Bearing with GreaseQUESTION: What should technicians keep in mind whenever servicing this type of bearing?

ANSWER: Thoroughly clean the bearing races and surfaces, any contaminants or debris could potentially shorten the service life of the bearings. The bearing cup and the cone experience wear together and should always be replaced at the same time. The bearings need to be greased by hand during install, commonly known Instead, they need to be greased by hand when installed, commonly referred to as “hand-packing”.

Topic: Wheel Hub Assemblies

QUESTION: Some vehicle models change the wheel bearings used by the OEM in the middle of model year. When this happens, how do you determine which aftermarket parts fit the vehicle?

ANSWER: When this occurs, the BCA catalog will specify the production month and year that the part change took place. The production month and year of a vehicle can be found on the manufacturers placard, which can be located inside the driver’s doorjamb.

For example, a 2003 Toyota Sienna will use either a WE60770 or WE61918 for the rear wheel bearing. If the vehicle was produced BEFORE or INCLUDING 01/2003 then it uses the WE61918. If the vehicle was produced AFTER 01/2003 then it uses the WE60770. A quick check of the vehicle production date will determine the correct part to use.

Topic: Seals

Wheel Seal for Tapered Roller BearingQUESTION: Are there any other components we should replace along with the bearings?

ANSWER: It’s best practice to always replace the seals when replacing bearings. The seals are responsible for keeping outside contaminants away from the bearing surfaces.

DO YOU HAVE A QUESTION?

Do you have a question about automotive wheel hubs, bearings or seals?

Use the form below to submit your question(s). Your question may be featured in an upcoming "Ask Matt" column, as well as right here on the BCA website. If we feature your question, we will send you a gift from BCA as a thank you for reaching out.