6238-ZZ bearing: complete specifications & equivalents
The 6238-ZZ is a ISO 15 radial bearing sized 190 x 340 x 55 mm (bore x OD x width) with ZZ sealing. Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NSK |
| Bore diameter d | 190 mm |
| Outer diameter D | 340 mm |
| Width B | 55 mm |
| Material | GCr15 |
| Seal / shield | ZZ |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 280 kN |
| Basic static load rating C0 | 282 kN |
| Mass | 22300 g |
| Manufacturer designation | NSK 6238ZZ |
| Standard | ISO 15 |
| Catalog version | NSK Rolling Bearings E1103 Part C |
| Last verified | 2026-09-24 |
Source: catalog reference (NSK Rolling Bearings E1103 Part C) · extracted 2026-09-24
Dimensions in inches & 6200-series range
| Bore d | 7.48 in |
|---|---|
| Outer diameter D | 13.386 in |
| Width B | 2.165 in |
| ISO bore code | 38 |
| Radial section height (D−d)/2 | 75 mm |
| Smallest bore in 6200-series | 10 mm |
| Largest outer diameter in 6200-series | 440 mm |
| Width range across 6200-series | 9–72 mm |
| Bore position in 6200-series (smallest first) | 31 of 34 |
| Bore above smallest 6200-series size | 180 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 6238 | ISO-INTERCHANGE | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | ISO 15 envelope interchange; NSK suffix ZZ maps to industry-neutral ZZ. Verify seal design, grease and speed rating per brand catalogue. |
Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.
How the 6238-ZZ model number is decoded
In the 6200-series (ISO 15 diameter series 2) the last two digits encode the bore: 6238 carries bore code 38 = 190 mm. Outside diameter 340 mm and width 55 mm come from the ISO 15 boundary-dimensions general plan. Suffix -ZZ denotes two non-contact metallic shields; they retain grease and block coarse debris but are not liquid-tight. For normal-load mounting with a rotating inner ring on a 190 mm shaft, typical catalogue practice is a m6 shaft seat with an H7 housing bore — verify against the actual load direction and magnitude.
Typical equipment & failure modes
Common applications
- heavy conveyors
- pulp and paper machinery
- medium and heavy industrial drives
- large gearboxes
Known failure patterns
- fine-particle abrasion when non-contact shields let dust past in dirty duty
- grease aging in the shield-for-life cavity with no relubrication path
- false brinelling from vibration while the shaft is stationary
- fretting corrosion on a loose shaft seat
Selection pitfalls — read before you substitute
- Mount this 190 mm bore bearing by heating the inner ring (induction heater, max 120 °C) — never drive it home through the outer ring or balls, that brinells the raceways.
- The 62xx light series is the default general-purpose section at 190 mm bore; before upgrading to a 6338 for extra capacity, confirm the housing accepts a 340 mm OD and 55 mm width — it is not a drop-in swap.
- ZZ shields are non-contact: 6238-ZZ blocks chips and coarse dust but is not waterproof — do not install it expecting a pressure-wash seal, step up to 6238-2RS for that.
- Shielded 6238-ZZ units are typically greased for life; prying the shields out for regreasing usually bends them and leaves a gap that throws grease in service.
- A 190 mm bore listing showing the right d/D/B but no standard or precision-class reference may be a loose-tolerance import; measure bore/OD spread before fitting it to a machined shaft.
- NSK catalogues the shielded version as 6238ZZ — suffix ZZ, two non-contact steel shields; the industry-neutral page spelling is -ZZ. Quote the NSK designation when ordering.
- The 280/282 kN ratings, mass 22300 g here are NSK Rolling Bearings E1103 Part C catalogue figures for 6238ZZ; this seal/size combination has no counterpart in the SKF 17000 extract used elsewhere on this site, so the page rests on a single manufacturer source — internal geometry and ratings legitimately differ between brands, so re-verify before substituting in a rated drive.
Frequently asked questions
What are the dimensions of a 6238-ZZ bearing?
A 6238-ZZ deep-groove ball bearing has a 190 mm bore, 340 mm outer diameter and 55 mm width (7.48 × 13.386 × 2.165 in), per ISO 15 boundary dimensions. It is fitted with two non-contact metallic shields.
How does the 6238 bore code work?
The last two digits of 6238 are bore code 38, giving 38 × 5 = 190 mm bore. The 340 mm outside diameter and 55 mm width follow the ISO 15 diameter series, not the bore code alone.
What does the ZZ suffix on 6238-ZZ mean?
ZZ means two non-contact sheet-metal shields, one each side. They retain factory grease and block coarse particles with little friction, but do not seal against liquids, fine dust or pressure washing.
How does the 6200 compare with other series at the same 190 mm bore?
The '2' is the light diameter series: 340×55 mm with a 75.0 mm radial section at 190 mm bore. A 6338 on the same bore is larger and higher-rated; a 6038 is smaller and lower-rated.
What is the NSK designation and catalogue data for 6238-ZZ?
In the NSK Rolling Bearings catalogue (E1103 Part C) this size is listed as 6238ZZ — two non-contact steel shields (NSK suffix ZZ), 190×340×55 mm per ISO 15. Quoted values: C 280 kN, C0 282 kN, mass 22300 g. The industry-neutral page spelling 6238-ZZ follows the seal-suffix convention used across this site, not NSK order-number spelling. Reference and limiting speeds are not tabulated in the E1103 dimension tables used here; consult NSK speed tables before high-speed service.
Reviewed & verified by the MPN Base engineering desk against source catalog NSK Rolling Bearings E1103 Part C on 2026-09-24. Read our editorial & correction policy.