NJ248 bearing: complete specifications & equivalents
The NJ248 is a ISO 15 radial bearing sized 240 x 440 x 72 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 240 mm |
| Outer diameter D | 440 mm |
| Width B | 72 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 1040 kN |
| Basic static load rating C0 | 1340 kN |
| Fatigue load limit Pu | 113 kN |
| Limiting speed (mechanical) | 1500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 49200 g |
| Manufacturer designation | NTN NJ248 |
| 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 & NJ200-series range
| Bore d | 9.449 in |
|---|---|
| Outer diameter D | 17.323 in |
| Width B | 2.835 in |
| ISO bore code | 48 |
| Radial section height (D−d)/2 | 100 mm |
| Smallest bore in NJ200-series | 15 mm |
| Largest outer diameter in NJ200-series | 580 mm |
| Width range across NJ200-series | 11–92 mm |
| Bore position in NJ200-series (smallest first) | 32 of 36 |
| Bore above smallest NJ200-series size | 225 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NJ248-MA | SKF | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
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 NJ248 model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, NJ248 appears as a 240 mm bore single-row cylindrical roller bearing (1040 kN C / 1340 kN C0) with a pressed sheet-steel cage, listed to the ISO 15 boundary plan. Numbering ties NJ248 to its envelope: type code NJ, series NJ200, 240 mm bore; the 440×72 mm outline therefore swaps dimensionally with other ISO 15 bearings of the same code, though rib arrangements differ by prefix. The 72 mm width and 100.0 mm section put the NJ200 series in the standard section; wide 22/23 variants at the same bore change OD, width and heat generation and are not drop-in swaps. Thermal planning around the 1,500 r/min grease ceiling should include the cage type (a pressed sheet-steel cage) and oil-flow option to 1,700 r/min for continuously high-duty 240 mm positions. After mounting verify the outer ring slides axially by hand at ambient temperature; a stuck float ring in a NJ248 non-locating position preloads the bearing when the shaft grows.
Typical equipment & failure modes
Common applications
- large turbine and generator rotor bearings
- wind-turbine gearbox planet and rotor shafts
- ship propulsion line shafts and reduction gears
- mining SAG/ball-mill drive shafts
Known failure patterns
- roller smearing (microwelding) at start-up before the oil film builds under insufficient radial load
- pressed-steel cage pocket wear when rollers skid at light load or too-thin lubricant
- grease starvation and cage drag when relubrication intervals are extended past the grease life
- brinelling from static overload or impact during handling
- hard-particle indentation of raceways in unfiltered oil or open arrangements
Selection pitfalls — read before you substitute
- At 240 mm bore, oil-lubricated arrangements toward 1,700 r/min need positive flow and drain design; the 49200 g NJ248 ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- Grease limiting speed 1,500 r/min and oil 1,700 r/min are different limits for NJ248: the first is the cage/lubricant mechanical ceiling, the second assumes real oil flow rather than an oil bath.
- The 100.0 mm section at 240 mm bore leaves a narrow oil path; with the standard cage the relubrication groove and oil-level design must keep grease from churning in the 72 mm-wide cavity.
- Wide (22/23) and light (10/49) executions at 240 mm bore share bore but not OD/width; check the full NJ200 series code before substituting, because housing and shoulder geometry will not interchange.
- Open NJ248 units need application-supplied sealing and a defined lubricant schedule; film thickness is the first failure mode for line contact when viscosity drops at the 240 mm contact.
- The 1040/1340 kN ratings, 113 kN Pu and 49200 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NJ248 (standard execution); other makes sharing the ISO 15 envelope revise internal geometry without changing the order number, so keep the 2203E reference with the specification for critical drives.
Frequently asked questions
What are the dimensions and catalogue data of NJ248?
NJ248 is an NTN NJ single-row cylindrical roller bearing to ISO 15: 240 mm bore, 440 mm OD and 72 mm width (9.449 × 17.323 × 2.835 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 1040 kN, C0 1340 kN, Pu 113 kN, grease limiting speed 1,500 r/min, oil 1,700 r/min, mass about 49200 g. It is open, with a pressed sheet-steel cage.
What is the difference between NU, NJ, NUP, N and NF cylindrical roller bearings?
The prefix states the rib arrangement: NU has two outer-ring ribs and a ribless inner ring (float, no axial load); NJ adds ribs for one-direction location; NUP adds a loose L-ring to locate both directions; N has two inner-ring ribs and a separable outer ring; NF has one rib per ring for one-direction guidance. NJ248 is two integral ribs on the inner ring and one rib on the outer ring — it locates the shaft in one axial direction.
What do the EA, E and ＊ suffixes mean on NTN cylindrical roller bearings?
EA is NTN's high-capacity design with a pressed sheet-steel cage and optimised roller complement in the same ISO 15 envelope; E marks the high-capacity design at the larger bores; the ＊ symbol printed before the code in the NTN catalogue marks the ULTAGE new-generation specification and is not typed as part of the order number. NJ248 is supplied in the standard open execution shown in the table.
Can NJ248 take axial load and locate a shaft?
the NJ design accepts axial load in one direction and provides one-way shaft location. For two-direction location use an NUP execution or an NJ pair with loose rib rings.
What do Fw and Ew mean for NJ248?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 295 mm, Ew 385 mm. The nominal bore/OD remain 240/440 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 1,500 r/min grease / 1,700 r/min oil.
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.