NUP344 bearing: complete specifications & equivalents
The NUP344 is a ISO 15 radial bearing sized 220 x 460 x 88 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 220 mm |
| Outer diameter D | 460 mm |
| Width B | 88 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 1320 kN |
| Basic static load rating C0 | 1570 kN |
| Fatigue load limit Pu | 133 kN |
| Limiting speed (mechanical) | 1400 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 71700 g |
| Manufacturer designation | NTN NUP344 |
| 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 & NUP300-series range
| Bore d | 8.661 in |
|---|---|
| Outer diameter D | 18.11 in |
| Width B | 3.465 in |
| ISO bore code | 44 |
| Radial section height (D−d)/2 | 120 mm |
| Smallest bore in NUP300-series | 20 mm |
| Largest outer diameter in NUP300-series | 580 mm |
| Width range across NUP300-series | 15–108 mm |
| Bore position in NUP300-series (smallest first) | 29 of 32 |
| Bore above smallest NUP300-series size | 200 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NUP344 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; brand-specific OEM equivalents (NSK/FAG/NTN) pending multi-source data. |
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 NUP344 model number is decoded
NTN lists NUP344 on the 220×460 mm envelope, 88 mm wide: a line-contact radial bearing with a pressed sheet-steel cage and a grease limiting speed of 1,400 r/min. The leading NUP defines the rib arrangement (inner ring two ribs + loose L-ring); the dimension-series digits and the two-digit bore code resolve to 220 mm, with 460 mm OD and 88 mm width from the ISO 15 general plan. NTN prints the raceway diameters for this size — Fw 284 mm and Ew 396 mm — the envelope inside the 220/460 mm bore/OD where the rollers actually run. Speed ratio check: limiting 1,400 r/min is .88 of the 1,600 r/min oil value for NUP344; grease-churn heating closes that gap as fill quantity rises. After mounting verify the outer ring slides axially by hand at ambient temperature; a stuck float ring in a NUP344 non-locating position preloads the bearing when the shaft grows.
Typical equipment & failure modes
Common applications
- offshore drawworks and winch drums
- heavy press and large gearbox main shafts
- rolling-mill work-roll and backup-roll positions
- large turbine and generator rotor bearings
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
- micro-pitting when the EHL film falls below the composite roughness at high specific load
- edge loading from shaft deflection beyond the 3–4 arc-minute alignment limit
- brinelling from static overload or impact during handling
Selection pitfalls — read before you substitute
- At 220 mm bore, oil-lubricated arrangements toward 1,600 r/min need positive flow and drain design; the 71700 g NUP344 ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- Never press either ring through the roller complement when fitting: mounting force goes through the ring faces, or the 460 mm race brinells and releases as vibration within hours.
- Do not replace NUP344 with a deep-groove ball bearing on rating alone: line contact gives 1320 kN radial capacity but the bearing only accepts small sustained axial guidance loads and misalignment tolerance is only 3–4 arc-minutes.
- The 88 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 220 mm inner ring.
- The NUP rib arrangement is not interchangeable with another prefix on the same 220 mm seat: inner ring two ribs + loose L-ring. Swapping NU for NJ changes axial location behaviour even though the 460×88 mm envelope matches.
- The 1320/1570 kN ratings, 133 kN Pu and 71700 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NUP344 (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 NUP344?
NUP344 is an NTN NUP single-row cylindrical roller bearing to ISO 15: 220 mm bore, 460 mm OD and 88 mm width (8.661 × 18.11 × 3.465 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 1320 kN, C0 1570 kN, Pu 133 kN, grease limiting speed 1,400 r/min, oil 1,600 r/min, mass about 71700 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. NUP344 is the NJ rib arrangement plus a loose L-shaped rib ring on the inner ring — it locates the shaft in both axial directions.
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. NUP344 is supplied in the standard open execution shown in the table.
Can NUP344 take axial load and locate a shaft?
the NUP design provides two-direction axial location via its loose rib ring, for light/moderate thrust guidance. The loose rib ring still only suits light/short-duration axial guidance; heavy thrust belongs to a dedicated thrust bearing.
What do Fw and Ew mean for NUP344?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 284 mm, Ew 396 mm. The nominal bore/OD remain 220/460 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 1,400 r/min grease / 1,600 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.