23256EMD1 bearing: complete specifications & equivalents
The 23256EMD1 is a ISO 15 radial bearing sized 280 x 500 x 176 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 280 mm |
| Outer diameter D | 500 mm |
| Width B | 176 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass, machined (M1) |
| Basic dynamic load rating C | 3770 kN |
| Basic static load rating C0 | 5340 kN |
| Fatigue load limit Pu | 193 kN |
| Limiting speed (mechanical) | 740 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 152000 g |
| Manufacturer designation | NTN 23256EMD1 |
| Standard | ISO 15 |
| Catalog version | NTN Ball and Roller Bearings CAT.No.2203E |
| Last verified | 2026-10-01 |
Source: catalog reference (NTN Ball and Roller Bearings CAT.No.2203E) · extracted 2026-10-01
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN Ball and Roller Bearings CAT.No.2203E); NTN® is a trademark of NTN Corporation, used here for identification only — mpnbase is not an authorized NTN distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at ntnglobal.com.
Dimensions in inches & 23200-series range
| Bore d | 11.024 in |
|---|---|
| Outer diameter D | 19.685 in |
| Width B | 6.929 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 110 mm |
| Smallest bore in 23200-series | 90 mm |
| Largest outer diameter in 23200-series | 1360 mm |
| Width range across 23200-series | 52.4–475 mm |
| Bore position in 23200-series (smallest first) | 16 of 34 |
| Bore above smallest 23200-series size | 190 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 23256EMKD1 | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same NTN 23200-series envelope, cage and ratings; this is the cylindrical-bore execution of the tapered-bore 23256EMKD1 (K/K30 sleeve or tapered-seat mounting). Verify shaft arrangement. |
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 23256EMD1 model number is decoded
23256EMD1 is the EM machined-brass-cage execution of NTN's spherical roller range for a 280 mm shaft — 3770 kN basic dynamic capacity in a 152000 g, open ISO 15 envelope. Digit by digit the code reads as spherical-roller dimension series plus 280 mm bore; the 176 mm width is the wide ISO 15 section, which is why spherical rollers interchange dimensionally but not in cage or rating detail. Pu 193 kN is the catalogue fatigue load limit for 23256EMD1, used in the adjusted-life equation at contaminated or partial-film conditions typical of mining and vibrating duty. Speed planning: 740 r/min grease limiting speed is the cage/kinematic ceiling and 950 r/min is the oil-lubricated value for the 280 mm bore; vibrating screens rarely approach either and are load/cage limited instead. Check the self-aligning movement after fitting: the housing should pivot freely around the sphered outer raceway; a pinched outer ring removes the alignment capacity the bearing was selected for.
Typical equipment & failure modes
Common applications
- heavy vibrating screens and grizzly feeders
- offshore and marine propulsion shaftlines
- large wind-turbine main-shaft arrangements
- steel-mill and heavy crusher main shafts
Known failure patterns
- lubricant starvation at the centre rib area when the D1/W33 groove is not connected to a relubrication supply
- pressed EA cage fatigue under sustained vibration when minimum load is not maintained
- roller-end smearing during skidding starts under light load and high viscosity grease
- water-induced pitting in washdown or outdoor duty without effective external seals
- hard-particle indentation through the open arrangement in dusty mining duty
Selection pitfalls — read before you substitute
- At 280 mm bore 23256EMD1 is normally mounted on adapter/withdrawal sleeves with hydraulic assistance; follow the NTN drive-up angle or oil-injection procedure — manual nut tightening cannot set the multi-tonne seating correctly.
- Do not confuse EA and EM at the same number: 23256EMD1 carries EM machined-brass-cage; swapping to the other cage execution changes mass, speed behaviour and sometimes suitability for vibration, even though the 280×500 mm envelope is identical.
- The two roller rows must share load equally — a tilted spacer or unequal abutment on the 176 mm-wide ring loads one row only and shows as asymmetric race polish during inspection.
- Do not confuse EA and EM at the same number: 23256EMD1 carries EM machined-brass-cage; swapping to the other cage execution changes mass, speed behaviour and sometimes suitability for vibration, even though the 280×500 mm envelope is identical.
- The D1/W33 groove only helps if the housing has a matching grease passage; mounting a D1 23256EMD1 in a solid block with no port wastes the feature and leaves the centre rows under-lubricated.
- The 3770/5340 kN ratings, 193 kN Pu and 152000 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 23256EMD1 (EM machined-brass-cage/D1); another maker's same-envelope part revises internal geometry, so re-verify ratings and cage before substitution on vibrating or rated drives.
Frequently asked questions
What are the dimensions and catalogue data of 23256EMD1?
23256EMD1 is an NTN double-row spherical roller bearing to ISO 15: 280 mm bore, 500 mm OD and 176 mm width (11.024 × 19.685 × 6.929 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 3770 kN, C0 5340 kN, Pu 193 kN, grease limiting speed 740 r/min, oil 950 r/min, mass about 152000 g. It is open, with one-piece machined brass cage (EM high-capacity design).
What is the difference between the K/K30 tapered bore and the cylindrical bore versions?
23256EMD1 has a cylindrical bore and mounts directly on a machined shaft seat. Its tapered-bore counterpart is 23256EMKD1 (K = 1:12, or K30 = 1:30 on the wide series), intended for adapter/withdrawal-sleeve mounting.
What do EA and EM mean on NTN spherical roller bearings?
EA is the NTN standard-capacity/high-capacity execution with a pressed sheet-steel window cage; EM is the high-capacity execution with a one-piece machined brass cage. Both use the optimised symmetric-roller design, but cage identity changes mass, speed behaviour and suitability for duties like vibrating screens, so they are separate order numbers. 23256EMD1 is the EM machined-brass-cage execution, listed with the ＊ ULTAGE new-generation mark.
What do D1 and W33 mean on 23256EMD1?
D1 is NTN's outer-ring lubrication feature: an annular groove with oil holes around the outer ring, aligned with a housing grease port so lubricant reaches both roller rows directly. 23256EMD1 carries D1; W33 is the equivalent industry-spelled annular-groove-and-holes feature seen on other executions.
How much misalignment and axial load can 23256EMD1 take?
The sphered outer raceway compensates static and dynamic misalignment in the order of 1–2° (verify the exact 2203E figure for the 23200 series); beyond that, load concentrates on one roller row. Load is predominantly radial with a moderate axial share in either direction — 3770 kN C / 5340 kN C0 — but sustained pure axial load is not recommended because it unloads one row.
Reviewed & verified by the MPN Base engineering desk against source catalog NTN Ball and Roller Bearings CAT.No.2203E on 2026-10-01. Read our editorial & correction policy.