6205-2RS vs 6205-2Z: Same Dimensions, Different Bearing Specifications
6205-2RS and 6205-2Z share bore, outside diameter and width but differ in closure: contact seal versus metal shield. How to treat them in product data and when they are not interchangeable.
6205-2RS and 6205-2Z are the same size, 25 × 52 × 15 mm, but different bearings. 2RS indicates contact seals on both sides; 2Z indicates metal shields on both sides. They differ in sealing, friction and speed capability, so they are not interchangeable by default and must not be merged. In relationship terms: NOT_SAME_AS for deduplication, VARIANT_OF the 6205 family.
The deduplication playbook opens with this pair as the example of a near-miss. This page is the reference behind it: what the two suffixes mean, what they share, and how to record the difference so a matching rule can see it.
What they share
The base designation 6205 is a single-row deep groove ball bearing. Its boundary dimensions are bore 25 mm, outside diameter 52 mm, width 15 mm, as listed on SKF’s 6205 product page. Those boundary dimensions follow the ISO dimension plan, which is why the base number is portable across makers. Sealed and shielded versions of the same base size keep the same fit dimensions; confirm the width in the datasheet of the specific part.
What differs
| -2RS (contact seal) | -2Z (shield) | |
|---|---|---|
| Closure | Elastomer seal on both sides, lip touches the inner ring | Metal shield on both sides, normally not touching the inner ring |
| Protection | Closes the gap against contamination more fully | Keeps out larger particles; leaves a small gap |
| Friction | Seal contact adds friction | No seal rubbing |
| Speed capability | Generally lower for the same size | Generally higher for the same size |
| Typical fit for | Dust, splash or moisture exposure | Cleaner conditions, higher speeds |
The direction of each difference is documented by the makers. The magnitude is not a constant: limiting speed, torque and seal life are catalog values per bearing and per maker, so this page deliberately gives no numbers. For example, NSK’s catalogue lists both contact (DDU) and shield (ZZ) versions of a series with different grease limiting speeds, and SKF lists a limiting speed per part number on each product page.
Seal and shield terms are defined in the bearing data glossary; the suffix itself is covered in what 2RS means on a bearing and the bearing suffix reference.
Brand caveats
- SKF writes the contact seal as
2RS1(nitrile rubber, both sides) and the shield as2Z. SKF’s 6206-2RS1 page lists contact seals. - NSK writes the same ideas as
DDU(rubber contact seals, both sides) andZZ(steel shields). See NSK’s deep groove ball bearing catalogue. - A bare
-2RSis common in distributor feeds and some makers’ ranges. Do not assume it equals a specific maker’s2RS1seal material without checking. - For brand cross-equivalence of seal codes, read Is It the Same Bearing?; this page does not repeat that table.
Normalized product-record comparison (illustrative / synthetic)
| Attribute | Record 1 | Record 2 |
|---|---|---|
| Supplier SKU (synthetic) | SUP-62052RS | SUP-62052Z |
| Raw part number | 6205-2RS | 6205-2Z |
| Base designation | 6205 | 6205 |
| Bore / OD / width (mm) | 25 / 52 / 15 | 25 / 52 / 15 |
| Seal type | contact seal, both sides | shield, both sides |
| Seal sides | 2 | 2 |
| Pair outcome | Differ on seal type: identity-critical |
supplier_sku,raw_pn,base_designation,bore_mm,od_mm,width_mm,closure_type,closure_sides
SUP-62052RS,6205-2RS,6205,25,52,15,contact_seal,2
SUP-62052Z,6205-2Z,6205,25,52,15,shield,2Illustrative / synthetic. With closure_type as a separate field, a rule can treat dimensions as agreeing and closure as a hard difference. Without it, text similarity between 6205-2RS and 6205-2Z is very high, which is exactly why they get merged by mistake. The bearing decoder returns the seal suffix as its own value.
Relationship terminology
| Editorial label | Claro relationship | For this pair |
|---|---|---|
| SAME_TRADE_ITEM | SAME_AS | No |
| Near-miss to remember | NOT_SAME_AS | Yes: block the merge and skip re-review |
| Shared family | VARIANT_OF (the 6205 family) | Yes: group under one family, show the seal option |
| TECHNICALLY_EQUIVALENT / COMPATIBLE_SUBSTITUTE | EQUIVALENT_TO is for a different maker; substitution here is conditional | Not by default; only with application evidence |
| UNKNOWN | Review | If the seal suffix is missing from a record |
Definitions of these edges are in Product Relationship Types. The same discipline applies to quantity: a shared part number does not make two sellable units identical, as in same MPN, different pack sizes.
Recording it in the catalog
The ball bearing attribute template lists seal or shield type among the attributes to capture per SKU. Store it as a controlled value, keep the raw suffix as source data, and make the closure type part of the identity check.
Source and evidence
- 6205 dimensions: SKF 6205 product page.
- Contact seal (SKF 2RS1): SKF 6206-2RS1 page, same series logic.
- Contact (DDU) and shield (ZZ) definitions and the speed trade-off: NSK deep groove ball bearings catalogue.
- These sources were consulted through search extracts; see the Needs review note.
Related
Playbook
Deduplicate a Product Catalog
The matching and review process.
Tool
Bearing Decoder
Split a designation into fields.
Guide
Same MPN, Different Pack Sizes
Another near-miss that must not be merged.
Attribute Library
Ball Bearing Attributes
Fields to capture per SKU.
Guide
Is It the Same Bearing?
Cross-brand seal codes.
Guide
Product Relationship Types
NOT_SAME_AS, VARIANT_OF and more.
FAQ
Is a 6205-2RS the same as a 6205-2Z?
Can I swap a 6205-2Z for a 6205-2RS?
How should 6205-2RS and 6205-2Z be recorded in a catalog?
Does 2RS mean the same thing for every brand?
Claro
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