NUP304EA bearing: complete specifications & equivalents
The NUP304EA is a ISO 15 radial bearing sized 20 x 52 x 15 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 20 mm |
| Outer diameter D | 52 mm |
| Width B | 15 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 37.5 kN |
| Basic static load rating C0 | 26.9 kN |
| Fatigue load limit Pu | 3.25 kN |
| Limiting speed (mechanical) | 13000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 147 g |
| Manufacturer designation | NTN NUP304EA |
| 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 | 0.787 in |
|---|---|
| Outer diameter D | 2.047 in |
| Width B | 0.591 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 16 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) | 1 of 32 |
| Bore above smallest NUP300-series size | 0 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NUP304EA | 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 NUP304EA model number is decoded
NUP304EA belongs to the NTN cylindrical roller range in NTN Ball and Roller Bearings CAT.No.2203E, under the ＊ ULTAGE new-generation specification: line-contact rollers between ground raceways for a 37.5 kN dynamic rating in the 20 mm bore. Numbering ties NUP304EA to its envelope: type code NUP, series NUP300, 20 mm bore; the 52×15 mm outline therefore swaps dimensionally with other ISO 15 bearings of the same code, though rib arrangements differ by prefix. At 18,000 r/min with oil versus 13,000 r/min with grease (a 5,000 r/min band), lubrication choice for NUP304EA is a thermal decision, not just a sealing one. Selection arithmetic: Pu 3.25 kN is the fatigue load limit feeding the adjusted-life equation, and the C0/C ratio of 0.72 (26.9/37.5 kN) shows the high-static-capacity proportioning of this 20 mm bore. Mount the separable inner ring + roller assembly on the shaft first and slide the outer ring into the housing; never press the outer ring through the rollers of NUP304EA.
Typical equipment & failure modes
Common applications
- appliance and office-machine drives
- agricultural PTO and implement gear shafts
- small conveyor and fan rotor positions
- small electric-motor armature shafts
Known failure patterns
- inner-ring raceway spalling from overload in the line-contact Hertzian zone
- pressed-steel cage pocket wear when rollers skid at light load or too-thin lubricant
- micro-pitting when the EHL film falls below the composite roughness at high specific load
- hard-particle indentation of raceways in unfiltered oil or open arrangements
- hard-particle indentation of raceways in unfiltered oil or open arrangements
Selection pitfalls — read before you substitute
- Small 20 mm-bore cylindrical rollers are skid-sensitive: ensure the radial load exceeds the minimum-load floor at operating speed, or the NUP304EA rollers smear even with correct grease.
- Wide (22/23) and light (10/49) executions at 20 mm bore share bore but not OD/width; check the full NUP300 series code before substituting, because housing and shoulder geometry will not interchange.
- The EA high-capacity roller complement changes the load figure versus the basic execution of the same number; the 37.5/26.9 kN pair here belongs to NUP304EA as printed, not to the bare size.
- Never press either ring through the roller complement when fitting: mounting force goes through the ring faces, or the 52 mm race brinells and releases as vibration within hours.
- Grease limiting speed 13,000 r/min and oil 18,000 r/min are different limits for NUP304EA: the first is the cage/lubricant mechanical ceiling, the second assumes real oil flow rather than an oil bath.
- The 37.5/26.9 kN ratings, 3.25 kN Pu and 147 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NUP304EA (EA pressed-steel-cage 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 NUP304EA?
NUP304EA is an NTN NUP single-row cylindrical roller bearing to ISO 15: 20 mm bore, 52 mm OD and 15 mm width (0.787 × 2.047 × 0.591 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 37.5 kN, C0 26.9 kN, Pu 3.25 kN, grease limiting speed 13,000 r/min, oil 18,000 r/min, mass about 147 g. It is open, with the EA high-capacity 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. NUP304EA 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. This page's bearing carries the EA pressed-steel-cage execution.
Can NUP304EA 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 NUP304EA?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 27.5 mm, Ew 45.5 mm. The nominal bore/OD remain 20/52 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 13,000 r/min grease / 18,000 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.