Attribute Schema Library
Attribute schemaautomotive aftermarket

Wheel Bearing Attributes

Wheel bearings cover two unrelated things sold under one category name: loose bearings and races that press into a knuckle, and bolt-on hub units that arrive with the flange, studs, and ABS encoder assembled. A distributor carries both, under PCdb terminologies like Wheel Bearing and Wheel Bearing & Hub Assembly.

Buyers are technicians, jobbers, and DIY installers working from a vehicle, not a part number. They arrive through a year/make/model lookup, then need spec detail to confirm the box matches the corner of the car on the lift.

The data is hard for a specific reason: identifying specs live in three incompatible places. Fitment lives in ACES application records. Dimensions live in the manufacturer PDF spec guide. Everything a technician actually asks — does it include the sensor, what is the axle nut torque, how many splines — is on the install sheet in the box, which never reaches the PIM. Suppliers send the same attribute six ways: 5x114.3 and 5x4.5 are the same bolt circle, Gen 3 and Generation III are the same design, and "w/ABS" means whatever that supplier decided.

Core

Every SKU needs these. Without them the record is not a product, it is a row.

Part Terminology (PCdb Part Type)
enum
Wheel Bearing & Hub Assembly

Separates a press-in bearing from a bolt-on hub unit from a kit. Drives which other attributes are even valid on the record.

Manufacturer Part Number (MPN)
identifier
HA590243

The primary key buyers and jobbers cross-reference on. Required by every marketplace and every ACES/PIES feed.

Vehicle Fitment (ACES Application)
text
2015-2020 Ford F-150, 4WD, Front

Nobody shops this category by dimension first. Year/make/model/submodel/drive is the entry path to the entire catalog.

Position (Axle / Side)
enum
Front Left

Front and rear units are rarely interchangeable, and left/right differ once a sensor pigtail or ABS routing is integrated.

Bearing Generation
enum
Gen 3

Tells the installer whether a press is needed. Gen 1 presses into the knuckle; Gen 2 and Gen 3 bolt on.

Bearing Type
enum
Double-row angular contact ball

Double-row angular contact ball dominates hub units; tapered roller still runs RWD, trailer, and heavy-duty corners.

Bore Diameter
number · mm
45

Identity dimension for a loose bearing. Must match the spindle or stub axle it rides on.

Outside Diameter
number · mm
84

Must match the knuckle or hub housing bore. Second half of the identity triple for a press-in bearing.

Differentiating

What buyers actually compare on. This is where catalogs win or lose the filter.

Bearing Width
number · mm
39

Third of the identity triple. Wrong width seats at the wrong depth and mis-sets the ABS air gap.

Wheel Stud Quantity
number
6

First filter a buyer touches on a hub unit. 4, 5, 6, and 8 stud flanges are all in current production.

Stud Bolt Circle Diameter (PCD)
number · mm
139.7

Distinguishes hubs that are otherwise dimensionally identical. 5x114.3 and 5x120 look the same in a photo.

Flange Bolt Hole Quantity
number
4

How the unit mounts to the knuckle on Gen 2/Gen 3. Three- and four-bolt flanges are both common.

Hub Pilot Diameter
number · mm
78.0

The centring register. If the pilot is wrong the unit will not seat in the knuckle regardless of bolt pattern.

Spline Quantity
number
29

Driven-axle hubs only. A 29-spline hub will not accept a 32-spline CV stub, and the counts are invisible in photos.

ABS Encoder / Sensor Configuration
enum
Integrated magnetic encoder; sensor not included

The single largest source of wrong-part returns here. Encoder-only, integrated sensor, and no ABS are three different SKUs.

Compliance & identifiers

Standards, regulatory data, and the identifiers channels reject you for missing.

GTIN / UPC
identifier
00053893432199

Required to list on Amazon and to syndicate through program group and jobber catalogs. No GTIN, no channel.

Country of Origin
identifier
Germany

Drives duty classification, government and fleet bid eligibility, and marketplace disclosure fields.

Prop 65 Warning Required
boolean
Yes

California disclosure obligation. Marketplaces expect the flag and the warning text at the item level.

The fields that aren't in the schema at all

What most wheel bearings catalogs are missing.

The table above is the schema most catalogs already have. These are the attributes that usually aren't in it — each one surfaced by a signal from the live market rather than by an audit of what's already there. This is what Anglera's Schema Foundry does on a real catalog, in this category.

Supplier signal
+ Axle Nut Torque Specification (Nm)

Technicians ask for the torque figure in pre-purchase questions and at parts counters. It is printed on the install sheet inside the box and appears in almost no catalog record.

Under-torqued nuts let the bearing walk and fail early; over-torqued nuts crush the inner race. Both come back as warranty claims on a part that was fine.

Review signal
+ Components Included / Kit Contents

Listings bury contents in free text — one reads 'Includes 2 Snap Rings, Bearing, Knuckle, Hub Assembly, Backing Plate, and Axle Nut' as a sentence, not as filterable fields.

Installer opens the box mid-job and finds no studs or no axle nut. Vehicle sits on the lift, the counter eats the return, and the sale moves to whoever listed contents.

Review signal
+ Wheel Speed Sensor Cable Length & Connector Type

Gen 3 hubs with integrated sensors ship with a pigtail of a specific length and connector body. Catalogs expose a connector count at best, never the connector type or lead length.

Pigtail will not reach the harness or will not mate with the vehicle connector. Correct bearing, correct fitment, unusable part, guaranteed return.

Search signal
+ OE / Interchange Cross-Reference Numbers

Buyers arrive holding the number stamped on the failed part — an OE casting number or a rival brand's number — and search on it. Records carry only the house MPN.

Zero results on a query where the exact part is in stock. Buyer assumes no coverage and orders from a catalog that indexed the interchange.

Supplier signal
+ Dynamic Load Rating (C, kN) and L10 Basis

Manufacturer spec guides publish C and C0 per ISO 281; distributor records for the same bearing carry only bore, OD, and width. Fleet and heavy-duty buyers ask for the rating by name.

Loses upgrade and fleet RFQs outright. Without C there is no basis to justify a premium bearing over the cheapest unit that shares the same envelope.

How Schema Foundry finds these

Messy in, governed out.

The same value, spelled every way automotive aftermarket suppliers spell it. A filter only works once they agree.

Stud Bolt Circle Diameter (PCD)
5x114.35 x 4.55-114.3mm114,35x4.50"5 Lug 114.3
5 × 114.3 mm

5x4.5 and 5x114.3 are the identical hole pattern in different units. Left raw, they split one facet into two half-empty ones.

Bearing Generation
Gen 3GEN33rd GenerationGeneration IIIG3Gen. 3
Gen 3

This field decides whether the installer needs a press. Six spellings means the press/bolt-on filter silently drops most of the catalog.

ABS Encoder / Sensor Configuration
w/ABSWith ABSABS: Yesw/ ABS SensorNon-ABSw/o ABS
Integrated encoder, no sensor

'w/ABS' means encoder-only at one supplier and a full sensor pigtail at another. The ambiguity is the return, not the spelling.

Wheel Stud Thread Size
M14x1.514x1.5M14 x 1.501/2-201/2 in-20M12X1.25
M14 × 1.5

Inch and metric callouts in one column make the facet unusable. Suppliers also report stud shank diameter in this field instead of thread.

What buyers ask

Every one of these should be answerable from the attributes above. If it isn't, that's a gap.

  • Does this hub come with the ABS sensor, or just the tone ring?
  • Is this a press-in bearing or does it bolt onto the knuckle?
  • What's the axle nut torque spec?
  • How many splines — 29 or 32?
  • Do the wheel studs come already pressed in?
  • Is the bolt circle 5x114.3 or 5x120?
  • What OE part number does this replace?
  • Will the sensor pigtail reach my factory connector?

What channels require

The same SKU, different mandatory fields per destination.

Amazon (Automotive / Part Finder)
BrandMPNGTIN/UPCACES fitment (year/make/model/submodel)Part TerminologyProp 65 warning flag and text
eBay Motors (Parts Compatibility)
BrandMPNFitment / compatibility recordsPart TypeInterchange and OE numbersItem specifics: position, stud quantity
ACES/PIES feed to jobber & program catalogs
PCdb Part Terminology IDBrand AAIA IDPAdb values (generation, studs, ABS)GTINVCdb application recordsPackage UOM and dimensions
Distributor's own site filter rail
Position (axle/side)Bearing GenerationWheel Stud QuantityStud Bolt Circle DiameterABS Encoder / Sensor ConfigurationSpline Quantity

Wheel Bearings data, in practice

Should wheel bearings and hub assemblies be one schema or two?

One schema, gated by Part Terminology. A press-in Gen 1 bearing needs bore, OD, and width and has no flange, no studs, and no pilot. A Gen 3 hub unit needs stud quantity, bolt circle, flange bolt holes, pilot diameter, spline count, and ABS configuration, and its bore/OD are mostly irrelevant to the buyer. Splitting them into two schemas duplicates the identifiers, the fitment, and the compliance fields, and it breaks the year/make/model lookup that returns both. Gate the spec groups on terminology instead, and let the filter rail show only the facets valid for what the buyer is looking at.

Which standards actually apply to wheel bearings?

Fewer than vendors imply. Tapered roller bearings carry real designation and boundary dimension standards: ISO 355 for metric, ANSI/ABMA 19.1 (metric design) and 19.2 (inch design). Load ratings and rating life follow ISO 281 (dynamic, C) and ISO 76 (static, C0); tolerance classes follow ISO 492. Manufacturing quality is governed by IATF 16949. Data standards are ACES for fitment and PIES for product information, with PCdb terminologies, PAdb attributes, and VCdb applications underneath. Integrated hub units have no dedicated dimensional standard — their geometry is defined by the vehicle, which is exactly why fitment data carries the weight here.

We already have good ACES fitment. Isn't that enough?

Fitment answers 'does it fit my car.' It doesn't answer the questions that actually generate returns. Two hub units can both be correct for the same year/make/model and differ on sensor inclusion, pigtail connector, or whether studs ship pressed in. ACES has no field for those. It also does nothing for the buyer who arrives holding an OE casting number rather than a vehicle, or the fleet buyer who wants the dynamic load rating before approving an upgrade. Fitment gets the buyer to a shortlist; PIES attributes decide which SKU on that shortlist ships.

Why is 'with ABS' such a persistent problem in this category?

Because it's three states compressed into one boolean. A unit can have no ABS provision at all, an integrated magnetic encoder ring in the seal with no sensor, or an integrated encoder plus a wheel speed sensor on a pigtail. Suppliers use 'w/ABS' for the second and third interchangeably. The buyer filters 'with ABS', receives an encoder-only hub, and has no sensor. Fix it by replacing the boolean with an enum for encoder configuration and a separate boolean for sensor inclusion, then normalize every supplier's phrasing into those two fields rather than passing the phrase through.

More automotive aftermarket schemas

Automotive BatteriesAutomotive FiltersBelts & HosesBrake PadsShocks & StrutsSpark Plugs

Run this against your own wheel bearings.

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