NU1040 bearing: complete specifications & equivalents
The NU1040 is a ISO 15 radial bearing sized 200 x 310 x 51 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 200 mm |
| Outer diameter D | 310 mm |
| Width B | 51 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 430 kN |
| Basic static load rating C0 | 580 kN |
| Fatigue load limit Pu | 53.5 kN |
| Limiting speed (mechanical) | 2200 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 13700 g |
| Manufacturer designation | NTN NU1040 |
| 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 & NU1000-series range
| Bore d | 7.874 in |
|---|---|
| Outer diameter D | 12.205 in |
| Width B | 2.008 in |
| ISO bore code | 40 |
| Radial section height (D−d)/2 | 55 mm |
| Smallest bore in NU1000-series | 25 mm |
| Largest outer diameter in NU1000-series | 1090 mm |
| Width range across NU1000-series | 12–150 mm |
| Bore position in NU1000-series (smallest first) | 27 of 47 |
| Bore above smallest NU1000-series size | 175 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NU1040-ML | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 200×310×51 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
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 NU1040 model number is decoded
The NTN order number NU1040 denotes a 200×310×51 mm (7.874 × 12.205 × 2.008 in) cylindrical roller bearing in the NU1000 family, a pressed sheet-steel cage. The leading NU defines the rib arrangement (outer ring ribbed, inner ring ribless); the dimension-series digits and the two-digit bore code resolve to 200 mm, with 310 mm OD and 51 mm width from the ISO 15 general plan. With C 430 kN and C0 580 kN (C0/C ≈ 1.35) the bearing is proportioned for heavy radial load; the NU design carries no axial load and floats axially on both sides. Speed ratio check: limiting 2,200 r/min is .85 of the 2,600 r/min oil value for NU1040; grease-churn heating closes that gap as fill quantity rises. Keep the open bearing wrapped until fitting: the line-contact raceways of the 200 mm bore indent under a single hard particle, and the steel cage provides no sealing of its own.
Typical equipment & failure modes
Common applications
- wind-turbine gearbox planet and rotor shafts
- ship propulsion line shafts and reduction gears
- mining SAG/ball-mill drive shafts
- offshore drawworks and winch drums
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
- roller-end and raceway scoring from inadequate oil flow under heavy radial load
- hard-particle indentation of raceways in unfiltered oil or open arrangements
- edge loading from shaft deflection beyond the 3–4 arc-minute alignment limit
Selection pitfalls — read before you substitute
- At 200 mm bore, oil-lubricated arrangements toward 2,600 r/min need positive flow and drain design; the 13700 g NU1040 ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- The 55.0 mm section at 200 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 51 mm-wide cavity.
- Open NU1040 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 200 mm contact.
- Grease limiting speed 2,200 r/min and oil 2,600 r/min are different limits for NU1040: the first is the cage/lubricant mechanical ceiling, the second assumes real oil flow rather than an oil bath.
- Minimum radial load is frequently missed in oversized motor and fan selections: an underloaded NU1040 skids at 2,200 r/min and fails by smearing long before L10 fatigue.
- The 430/580 kN ratings, 53.5 kN Pu and 13700 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NU1040 (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 NU1040?
NU1040 is an NTN NU single-row cylindrical roller bearing to ISO 15: 200 mm bore, 310 mm OD and 51 mm width (7.874 × 12.205 × 2.008 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 430 kN, C0 580 kN, Pu 53.5 kN, grease limiting speed 2,200 r/min, oil 2,600 r/min, mass about 13700 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. NU1040 is two integral ribs on the outer ring and a ribless, separable inner ring — a non-locating bearing that lets the shaft float axially.
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. NU1040 is supplied in the standard open execution shown in the table.
Can NU1040 take axial load and locate a shaft?
the NU design carries no axial load and floats axially on both sides. Provide axial location with an adjacent locating bearing (angular-contact, deep-groove or a paired NJ/NUP set).
What do Fw and Ew mean for NU1040?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 229 mm, Ew 281 mm. The nominal bore/OD remain 200/310 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 2,200 r/min grease / 2,600 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.