NUP2318 bearing: complete specifications & equivalents
The NUP2318 is a ISO 15 radial bearing sized 90 x 190 x 64 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 90 mm |
| Outer diameter D | 190 mm |
| Width B | 64 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 360 kN |
| Basic static load rating C0 | 395 kN |
| Fatigue load limit Pu | 43.5 kN |
| Limiting speed (mechanical) | 3200 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 7790 g |
| Manufacturer designation | NTN NUP2318 |
| 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 & NUP2300-series range
| Bore d | 3.543 in |
|---|---|
| Outer diameter D | 7.48 in |
| Width B | 2.52 in |
| ISO bore code | 18 |
| Radial section height (D−d)/2 | 50 mm |
| Smallest bore in NUP2300-series | 20 mm |
| Largest outer diameter in NUP2300-series | 580 mm |
| Width range across NUP2300-series | 21–175 mm |
| Bore position in NUP2300-series (smallest first) | 15 of 31 |
| Bore above smallest NUP2300-series size | 70 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NUP2318-ECP | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 90×190×64 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 NUP2318 model number is decoded
NUP2318 is the extra-wide (23) section of the NTN NUP2300 dimension series for a 90 mm shaft — 360 kN of basic dynamic capacity in a 7790 g, open bearing. 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 90 mm, with 190 mm OD and 64 mm width from the ISO 15 general plan. The separable ring comes off without removing the roller assembly from the other ring, which eases inspection and lets the non-locating arrangement accommodate thermal shaft growth. The 4.0 kN-per-mm-bore figure (360 kN over 90 mm) lets a NUP2318 interchange candidate be screened quickly against the same-envelope ball or roller alternatives. Housing and shaft fillets must clear the ring chamfers of NUP2318; an oversized radius locks the ring on its face and tilts the 64 mm-wide seat.
Typical equipment & failure modes
Common applications
- large pump, turbine and compressor rotors
- rolling-mill auxiliary drive shafts
- crusher and vibrating-screen drive shafts
- marine gearbox and deck-machinery 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
- micro-pitting when the EHL film falls below the composite roughness at high specific load
- false brinelling on standby machines exposed to external vibration
- false brinelling on standby machines exposed to external vibration
Selection pitfalls — read before you substitute
- Induction-heat the 90 mm inner ring (max 120 °C) and mount it before fitting the outer ring; the ring mass makes square guidance essential — driving through the rollers brinells the 190 mm raceway.
- The 64 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 90 mm inner ring.
- The 50.0 mm section at 90 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 64 mm-wide cavity.
- Never press either ring through the roller complement when fitting: mounting force goes through the ring faces, or the 190 mm race brinells and releases as vibration within hours.
- The EA high-capacity roller complement changes the load figure versus the basic execution of the same number; the 360/395 kN pair here belongs to NUP2318 as printed, not to the bare size.
- The 360/395 kN ratings, 43.5 kN Pu and 7790 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NUP2318 (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 NUP2318?
NUP2318 is an NTN NUP single-row cylindrical roller bearing to ISO 15: 90 mm bore, 190 mm OD and 64 mm width (3.543 × 7.48 × 2.52 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 360 kN, C0 395 kN, Pu 43.5 kN, grease limiting speed 3,200 r/min, oil 3,800 r/min, mass about 7790 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. NUP2318 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. NUP2318 is supplied in the standard open execution shown in the table.
Can NUP2318 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 NUP2318?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 115 mm, Ew 165 mm. The nominal bore/OD remain 90/190 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 3,200 r/min grease / 3,800 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.