24128EMK30D1 bearing: complete specifications & equivalents
The 24128EMK30D1 is a ISO 15 radial bearing sized 140 x 225 x 85 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 140 mm |
| Outer diameter D | 225 mm |
| Width B | 85 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass, machined (M1) |
| Basic dynamic load rating C | 951 kN |
| Basic static load rating C0 | 1280 kN |
| Fatigue load limit Pu | 53.3 kN |
| Limiting speed (mechanical) | 1700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 12800 g |
| Manufacturer designation | NTN 24128EMK30D1 |
| 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 & 24100-series range
| Bore d | 5.512 in |
|---|---|
| Outer diameter D | 8.858 in |
| Width B | 3.346 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 42.5 mm |
| Smallest bore in 24100-series | 100 mm |
| Largest outer diameter in 24100-series | 1150 mm |
| Width range across 24100-series | 65–438 mm |
| Bore position in 24100-series (smallest first) | 5 of 32 |
| Bore above smallest 24100-series size | 40 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 24128EMD1 | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same NTN 24100-series envelope, cage and ratings; this is the tapered-bore execution (K30, 1:30) of the cylindrical-bore 24128EMD1 — mounting (adapter/withdrawal sleeve or tapered seat, drive-up) differs. 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 24128EMK30D1 model number is decoded
24128EMK30D1 is an NTN double-row spherical roller bearing: two rows of symmetric rollers on a sphered outer raceway, 140×225×85 mm to ISO 15, with one-piece machined brass cage (EM high-capacity design). Numbering ties 24128EMK30D1 to its envelope and execution: same-number EA versus EM or plain variants share the 140 mm bore but differ in cage and sometimes mass, so they are quoted as separate articles. The sphered outer raceway lets the inner-ring assembly pivot, accommodating shaft deflection and housing misalignment (around 1–2° for this class; use the 2203E value for the exact series) without edge loading the rollers. The 42.5 mm section height hosts the spherical roller geometry; shaft and housing fillet radii must clear the chamfer table so the 85 mm-wide ring seats fully on both sides. Supply grease through the D1 feature during commissioning and at the calculated interval, rotating the 140 mm bore assembly by hand to distribute it across both rows.
Typical equipment & failure modes
Common applications
- offshore and marine propulsion shaftlines
- large wind-turbine main-shaft arrangements
- steel-mill and heavy crusher main shafts
- mining shovel and dragline swing shafts
Known failure patterns
- raceway spalling at the roller ends when misalignment or deflection concentrates the line contact
- cage damage when a mounting force is applied through the roller set instead of the ring face
- sliding wear and heat when relubrication intervals ignore the groove (D1/W33) supply path
- hard-particle indentation through the open arrangement in dusty mining duty
- fretting corrosion between adapter sleeve and tapered bore when the drive-up is insufficient
Selection pitfalls — read before you substitute
- At 140 mm bore 24128EMK30D1 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.
- Adapter-sleeve mounting requires the correct sleeve series and locknut for the 140 mm shaft; a sleeve sized to bore alone ignores thread, width and the oil-injection option on large K seats.
- The D1/W33 groove only helps if the housing has a matching grease passage; mounting a D1 24128EMK30D1 in a solid block with no port wastes the feature and leaves the centre rows under-lubricated.
- Minimum load must be maintained even at rest under vibration: an unloaded 24128EMK30D1 on a stopped screen false-brinells; parking brakes and shaker isolation both matter.
- Minimum load must be maintained even at rest under vibration: an unloaded 24128EMK30D1 on a stopped screen false-brinells; parking brakes and shaker isolation both matter.
- The 951/1280 kN ratings, 53.3 kN Pu and 12800 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 24128EMK30D1 (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 24128EMK30D1?
24128EMK30D1 is an NTN double-row spherical roller bearing to ISO 15: 140 mm bore, 225 mm OD and 85 mm width (5.512 × 8.858 × 3.346 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 951 kN, C0 1280 kN, Pu 53.3 kN, grease limiting speed 1,700 r/min, oil 2,200 r/min, mass about 12800 g. It is open, with one-piece machined brass cage (EM high-capacity design) and a 1:30 tapered bore.
What is the difference between the K/K30 tapered bore and the cylindrical bore versions?
K30 denotes a 1:30 tapered bore (the wide 24100 series). 24128EMK30D1 mounts on a matching adapter or withdrawal sleeve on a plain 140 mm shaft and is driven up to a measured radial clearance; the cylindrical-bore counterpart is 24128EMD1.
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. 24128EMK30D1 is the EM machined-brass-cage execution, listed with the ＊ ULTAGE new-generation mark.
What do D1 and W33 mean on 24128EMK30D1?
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. 24128EMK30D1 carries D1; W33 is the equivalent industry-spelled annular-groove-and-holes feature seen on other executions.
How much misalignment and axial load can 24128EMK30D1 take?
The sphered outer raceway compensates static and dynamic misalignment in the order of 1–2° (verify the exact 2203E figure for the 24100 series); beyond that, load concentrates on one roller row. Load is predominantly radial with a moderate axial share in either direction — 951 kN C / 1280 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.