NU324E bearing: complete specifications & equivalents
The NU324E is a ISO 15 radial bearing sized 120 x 260 x 55 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 120 mm |
| Outer diameter D | 260 mm |
| Width B | 55 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 585 kN |
| Basic static load rating C0 | 610 kN |
| Fatigue load limit Pu | 61 kN |
| Limiting speed (mechanical) | 2400 rpm |
| Operating temperature | -40 to +120 °C |
| Manufacturer designation | NTN NU324E |
| 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 | 4.724 in |
|---|---|
| Outer diameter D | 10.236 in |
| Width B | 2.165 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 70 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) | 21 of 34 |
| Bore above smallest NU300-series size | 103 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NU324E | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the 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 NU324E model number is decoded
The NTN order number NU324E denotes a 120×260×55 mm (4.724 × 10.236 × 2.165 in) cylindrical roller bearing in the NU300 family, the high-capacity pressed-steel cage of the E execution. Numbering ties NU324E to its envelope: type code NU, series NU300, 120 mm bore; the 260×55 mm outline therefore swaps dimensionally with other ISO 15 bearings of the same code, though rib arrangements differ by prefix. At 2,800 r/min with oil versus 2,400 r/min with grease (a 400 r/min band), lubrication choice for NU324E is a thermal decision, not just a sealing one. Thermal planning around the 2,400 r/min grease ceiling should include the cage type (the high-capacity pressed-steel cage of the E execution) and oil-flow option to 2,800 r/min for continuously high-duty 120 mm positions. On NU arrangements confirm which ring is separable before heating: forcing the ribbed ring off over the roller complement damages the cage and rib faces.
Typical equipment & failure modes
Common applications
- mining SAG/ball-mill drive shafts
- offshore drawworks and winch drums
- heavy press and large gearbox main shafts
- rolling-mill work-roll and backup-roll positions
Known failure patterns
- roller smearing (microwelding) at start-up before the oil film builds under insufficient radial load
- cage distortion after a mounting blow carried through the roller set
- micro-pitting when the EHL film falls below the composite roughness at high specific load
- electrical pitting on VFD-driven motor shafts without grounding protection
- fretting corrosion on a loose rotating shaft seat
Selection pitfalls — read before you substitute
- At 120 mm bore, oil-lubricated arrangements toward 2,800 r/min need positive flow and drain design; the NU324E 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 260 mm race brinells and releases as vibration within hours.
- Minimum radial load is frequently missed in oversized motor and fan selections: an underloaded NU324E skids at 2,400 r/min and fails by smearing long before L10 fatigue.
- The EA high-capacity roller complement changes the load figure versus the basic execution of the same number; the 585/610 kN pair here belongs to NU324E as printed, not to the bare size.
- Grease limiting speed 2,400 r/min and oil 2,800 r/min are different limits for NU324E: the first is the cage/lubricant mechanical ceiling, the second assumes real oil flow rather than an oil bath.
- The 585/610 kN ratings, 61 kN Pu are NTN Ball and Roller Bearings CAT.No.2203E values for NU324E (E high-capacity 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 NU324E?
NU324E is an NTN NU single-row cylindrical roller bearing to ISO 15: 120 mm bore, 260 mm OD and 55 mm width (4.724 × 10.236 × 2.165 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 585 kN, C0 610 kN, Pu 61 kN, grease limiting speed 2,400 r/min, oil 2,800 r/min. It is open, with the high-capacity pressed-steel cage of the E execution.
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. NU324E 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. NU324E is supplied in the standard open execution shown in the table.
Can NU324E 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 NU324E?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 154 mm. The nominal bore/OD remain 120/260 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 2,400 r/min grease / 2,800 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.