Building an attribute schema for MRO & Industrial that buyers and AI can actually use
Why missing bore, housing, and load-rating fields drop MRO bearings from filtered search and AI answers, and how to structure the schema right

A maintenance planner shopping for a replacement pillow block bearing doesn't type "heavy-duty bearing for tough conditions." They type a bore diameter, a housing style, and a locking method, because that's what has to match the failed part on the line. If those three fields aren't structured data on the product page, the SKU doesn't rank low — it doesn't show up at all. Here's what an MRO & Industrial attribute schema needs, why gaps quietly delete SKUs from search and AI answers, and how to structure it so it holds up at scale.
Why MRO buyers filter first and never read
Industrial and MRO buyers are usually maintenance techs or procurement staff working from a failed part number or a bill of materials, not a product description. They already know the spec before they land on a page. The catalog's job is to confirm a match fast, not to persuade.
That means the buying motion is filter-first, and it breaks hard when specs live only in a PDF or a sentence. A distributor's own classification system compounds the problem: MRO catalogs typically run on broad schemes like UNSPSC or NAICS for category assignment, but those taxonomies were built to answer "what kind of thing is this," not "what bore size, what housing, what seal," as Verdantis notes in its breakdown of MRO data taxonomy. A part can be filed in exactly the right category and still be functionally invisible, because the category node has no opinion on the feature-level fields a buyer filters by.
Electrical distribution solved a version of this with ETIM, which forces every SKU in a class into the same fixed set of features. General industrial hardware — bearings, fasteners, hydraulics, power transmission — mostly hasn't gotten that standardization; ETIM's coverage is concentrated in electrical, HVAC, and building materials, not mechanical power transmission, per WISEPIM's overview of the ETIM classification model. So the discipline has to come from the distributor's own schema, applied consistently across suppliers who all describe the same part differently.
The attribute set that actually matters
For mounted bearings, insert bearings, pillow blocks, and flange units, the fields that drive filtered search and correct part selection fall into five groups:
| Category | Attributes |
|---|---|
| Dimensional | Bore diameter, shaft diameter, housing style (pillow block, flange, take-up, cartridge), bolt hole spacing, base-to-center height, overall length/width |
| Housing & materials | Housing material (cast iron, pressed steel, thermoplastic, stainless steel), insert bearing material, corrosion protection/coating |
| Locking & mounting | Locking method (set screw, eccentric collar, adapter sleeve), mounting orientation, expansion vs. non-expansion type |
| Sealing & lubrication | Seal type (labyrinth, triple-lip contact, felt), relube interval, grease fitting location/type, ambient temperature range |
| Performance & compliance | Dynamic load rating (C), static load rating (C0), max speed (RPM), ABMA/ISO standard reference |
Manufacturer engineering data pages consistently structure bearing specs this way — dimension, material, load rating, and speed limit as discrete numeric or coded fields, not prose — which is the format search filters and AI extraction need, as Schaeffler's bearing data reference shows. When a distributor's catalog collapses that same information into a marketing sentence, the structure the manufacturer already built gets thrown away on the way to the storefront.
Worked example: a mounted ball bearing
Here's what a typical raw supplier feed looks like next to what a filterable, AI-legible listing needs.
Raw feed description (as received from a manufacturer):
"2-bolt pillow block bearing unit, cast iron housing, set screw locking, for general industrial use, relubricatable."
That sentence is accurate and nearly useless for selection. It has no bore size, no load rating, no seal type. A buyer filtering for "1-3/16 inch bore, cast iron, set screw" will never see this SKU, and an AI answer engine summarizing options has nothing structured to cite.
Enriched attribute table:
| Attribute | Value |
|---|---|
| Bore diameter | 1-3/16 in (30.163 mm) |
| Housing style | 2-bolt pillow block |
| Housing material | Cast iron |
| Locking method | Set screw |
| Insert bearing type | Ball, wide inner ring |
| Seal type | Triple-lip contact seal |
| Dynamic load rating (C) | 15.9 kN |
| Static load rating (C0) | 9.6 kN |
| Max speed | 4,500 RPM |
| Relube interval | Grease fitting, standard NLGI 2 grease |
| Standard reference | ABMA 9 |
Same physical part. One is a sentence a human might skim; the other is a set of fields a filter, a comparison table, or a language model can actually use.
Ask an answer engine
Type "1 3/16 inch bore pillow block bearing cast iron set screw locking" into an AI shopping assistant today, and it can only surface SKUs where those five values exist as parseable data it can find — structured fields, a spec table, or schema markup on the page. A generative engine needs values it can lift with confidence, not a paragraph it has to interpret, which is a large part of why most B2B brands remain effectively absent from early-stage AI-driven product discovery, according to a 2025 industry survey on B2B AI visibility. Bore diameter, housing material, and load rating aren't just filter fields anymore — they're the vocabulary an answer engine needs to recommend a specific SKU by name instead of a category.
How to structure it
Two design decisions matter more than which taxonomy you pick.
First, separate global attributes (brand, price, weight, country of origin) from category-specific sets, and let the mounted-bearing set inherit from a broader power-transmission group so bore diameter and load rating stay consistent across pillow blocks, flange units, and take-up frames. Second, treat every field as something to be scored, not just populated — a bore diameter of 0 or a housing material of "steel" when the supplier doc says cast iron is worse than a blank field, because it fails silently in a filter instead of flagging for review.
That gap between designing an attribute set and actually filling it correctly, SKU by SKU, across every supplier who feeds a catalog, is where most MRO distributors run out of internal capacity. Anglera plugs into whatever PIM a distributor already runs, or works from a flat file if there isn't one, and does the enrichment work of extracting bore, housing, load, and seal values from supplier documentation, quality-scoring each field, and flagging what's missing — so the schema a team designs on a whiteboard actually gets filled in at catalog scale, instead of staying half-populated.
