NU1084 bearing: complete specifications & equivalents
The NU1084 is a ISO 15 radial bearing sized 420 x 620 x 90 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 420 mm |
| Outer diameter D | 620 mm |
| Width B | 90 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 1500 kN |
| Basic static load rating C0 | 2290 kN |
| Fatigue load limit Pu | 170 kN |
| Limiting speed (mechanical) | 950 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 89600 g |
| Manufacturer designation | NTN NU1084 |
| 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 | 16.535 in |
|---|---|
| Outer diameter D | 24.409 in |
| Width B | 3.543 in |
| ISO bore code | 84 |
| Radial section height (D−d)/2 | 100 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) | 38 of 47 |
| Bore above smallest NU1000-series size | 395 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NU1084-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 NU1084 model number is decoded
NU1084 is an NTN NU cylindrical roller bearing: two integral ribs on the outer ring and a ribless, separable inner ring — a non-locating bearing that lets the shaft float axially, inside the 420×620×90 mm ISO 15 envelope. On the NTN nameplate NU states which ring carries the ribs, which determines whether NU1084 floats or locates; the numeric remainder is the ISO 15 series and 420 mm bore reference, not a fit or clearance instruction. The 90 mm width and 100.0 mm section put the NU1000 series in the extra-light (10/49) section; wide 22/23 variants at the same bore change OD, width and heat generation and are not drop-in swaps. Selection arithmetic: Pu 170 kN is the fatigue load limit feeding the adjusted-life equation, and the C0/C ratio of 1.53 (2290/1500 kN) shows the high-static-capacity proportioning of this 420 mm bore. Keep the open bearing wrapped until fitting: the line-contact raceways of the 420 mm bore indent under a single hard particle, and the steel cage provides no sealing of its own.
Typical equipment & failure modes
Common applications
- rolling-mill work-roll and backup-roll positions
- large turbine and generator rotor bearings
- wind-turbine gearbox planet and rotor shafts
- ship propulsion line shafts and reduction gears
Known failure patterns
- roller smearing (microwelding) at start-up before the oil film builds under insufficient radial load
- cage wear accelerated when the EA high-capacity roller complement runs continuously above its thermal balance
- grease starvation and cage drag when relubrication intervals are extended past the grease life
- electrical pitting on VFD-driven motor shafts without grounding protection
- edge loading from shaft deflection beyond the 3–4 arc-minute alignment limit
Selection pitfalls — read before you substitute
- At 420 mm bore, oil-lubricated arrangements toward 1,100 r/min need positive flow and drain design; the 89600 g NU1084 ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- The 90 mm width and abutment faces must be square to the axis; a tilted spacer concentrates load across the roller set and shows as uneven raceway polish on the 420 mm inner ring.
- The NU rib arrangement is not interchangeable with another prefix on the same 420 mm seat: outer ring ribbed, inner ring ribless. Swapping NU for NJ changes axial location behaviour even though the 620×90 mm envelope matches.
- Grease limiting speed 950 r/min and oil 1,100 r/min are different limits for NU1084: the first is the cage/lubricant mechanical ceiling, the second assumes real oil flow rather than an oil bath.
- Open NU1084 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 420 mm contact.
- The 1500/2290 kN ratings, 170 kN Pu and 89600 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NU1084 (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 NU1084?
NU1084 is an NTN NU single-row cylindrical roller bearing to ISO 15: 420 mm bore, 620 mm OD and 90 mm width (16.535 × 24.409 × 3.543 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 1500 kN, C0 2290 kN, Pu 170 kN, grease limiting speed 950 r/min, oil 1,100 r/min, mass about 89600 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. NU1084 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. NU1084 is supplied in the standard open execution shown in the table.
Can NU1084 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 NU1084?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 470 mm, Ew 570 mm. The nominal bore/OD remain 420/620 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 950 r/min grease / 1,100 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.