NU332 bearing: complete specifications & equivalents
The NU332 is a ISO 15 radial bearing sized 160 x 340 x 68 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 160 mm |
| Outer diameter D | 340 mm |
| Width B | 68 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 775 kN |
| Basic static load rating C0 | 875 kN |
| Fatigue load limit Pu | 81 kN |
| Limiting speed (mechanical) | 2000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 30600 g |
| Manufacturer designation | NTN NU332 |
| 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 & NU300-series range
| Bore d | 6.299 in |
|---|---|
| Outer diameter D | 13.386 in |
| Width B | 2.677 in |
| ISO bore code | 32 |
| Radial section height (D−d)/2 | 90 mm |
| Smallest bore in NU300-series | 17 mm |
| Largest outer diameter in NU300-series | 620 mm |
| Width range across NU300-series | 14–109 mm |
| Bore position in NU300-series (smallest first) | 25 of 34 |
| Bore above smallest NU300-series size | 143 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NU332-ECML | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 160×340×68 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 NU332 model number is decoded
NU332 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 160×340×68 mm ISO 15 envelope. On the NTN nameplate NU states which ring carries the ribs, which determines whether NU332 floats or locates; the numeric remainder is the ISO 15 series and 160 mm bore reference, not a fit or clearance instruction. NTN prints the raceway diameters for this size — Fw 208 mm and Ew 292 mm — the envelope inside the 160/340 mm bore/OD where the rollers actually run. Speed ratio check: limiting 2,000 r/min is .87 of the 2,300 r/min oil value for NU332; grease-churn heating closes that gap as fill quantity rises. Heat the inner ring to max 120 °C for the 160 mm interference fit and support the ring face square during fitting; cocking over a keyway brinells the raceway before first rotation.
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
- inner-ring raceway spalling from overload in the line-contact Hertzian zone
- cage wear accelerated when the EA high-capacity roller complement runs continuously above its thermal balance
- 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 160 mm bore, oil-lubricated arrangements toward 2,300 r/min need positive flow and drain design; the 30600 g NU332 ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- The 68 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 160 mm inner ring.
- The 90.0 mm section at 160 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 68 mm-wide cavity.
- The 90.0 mm section at 160 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 68 mm-wide cavity.
- The NU rib arrangement is not interchangeable with another prefix on the same 160 mm seat: outer ring ribbed, inner ring ribless. Swapping NU for NJ changes axial location behaviour even though the 340×68 mm envelope matches.
- The 775/875 kN ratings, 81 kN Pu and 30600 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NU332 (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 NU332?
NU332 is an NTN NU single-row cylindrical roller bearing to ISO 15: 160 mm bore, 340 mm OD and 68 mm width (6.299 × 13.386 × 2.677 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 775 kN, C0 875 kN, Pu 81 kN, grease limiting speed 2,000 r/min, oil 2,300 r/min, mass about 30600 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. NU332 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. NU332 is supplied in the standard open execution shown in the table.
Can NU332 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 NU332?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 208 mm, Ew 292 mm. The nominal bore/OD remain 160/340 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 2,000 r/min grease / 2,300 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.