NU226 bearing: complete specifications & equivalents
The NU226 is a ISO 15 radial bearing sized 130 x 230 x 40 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 130 mm |
| Outer diameter D | 230 mm |
| Width B | 40 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 300 kN |
| Basic static load rating C0 | 340 kN |
| Fatigue load limit Pu | 35 kN |
| Limiting speed (mechanical) | 2900 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 6170 g |
| Manufacturer designation | NTN NU226 |
| 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 & NU200-series range
| Bore d | 5.118 in |
|---|---|
| Outer diameter D | 9.055 in |
| Width B | 1.575 in |
| ISO bore code | 26 |
| Radial section height (D−d)/2 | 50 mm |
| Smallest bore in NU200-series | 15 mm |
| Largest outer diameter in NU200-series | 580 mm |
| Width range across NU200-series | 11–92 mm |
| Bore position in NU200-series (smallest first) | 23 of 36 |
| Bore above smallest NU200-series size | 115 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NU226-ECP | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 130×230×40 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 NU226 model number is decoded
NU226 belongs to the NTN cylindrical roller range in NTN Ball and Roller Bearings CAT.No.2203E: line-contact rollers between ground raceways for a 300 kN dynamic rating in the 130 mm bore. The leading NU defines the rib arrangement (outer ring ribbed, inner ring ribless); the dimension-series digits and the two-digit bore code resolve to 130 mm, with 230 mm OD and 40 mm width from the ISO 15 general plan. The 40 mm width and 50.0 mm section put the NU200 series in the standard section; wide 22/23 variants at the same bore change OD, width and heat generation and are not drop-in swaps. Selection arithmetic: Pu 35 kN is the fatigue load limit feeding the adjusted-life equation, and the C0/C ratio of 1.13 (340/300 kN) shows the high-static-capacity proportioning of this 130 mm bore. After mounting verify the outer ring slides axially by hand at ambient temperature; a stuck float ring in a NU226 non-locating position preloads the bearing when the shaft grows.
Typical equipment & failure modes
Common applications
- wind-turbine gearbox planet and rotor shafts
- ship propulsion line shafts and reduction gears
- mining SAG/ball-mill drive shafts
- offshore drawworks and winch drums
Known failure patterns
- inner-ring raceway spalling from overload in the line-contact Hertzian zone
- cage distortion after a mounting blow carried through the roller set
- grease starvation and cage drag when relubrication intervals are extended past the grease life
- electrical pitting on VFD-driven motor shafts without grounding protection
- electrical pitting on VFD-driven motor shafts without grounding protection
Selection pitfalls — read before you substitute
- At 130 mm bore, oil-lubricated arrangements toward 3,400 r/min need positive flow and drain design; the 6170 g NU226 ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- Wide (22/23) and light (10/49) executions at 130 mm bore share bore but not OD/width; check the full NU200 series code before substituting, because housing and shoulder geometry will not interchange.
- Do not replace NU226 with a deep-groove ball bearing on rating alone: line contact gives 300 kN radial capacity but the bearing cannot carry the thrust duty a ball bearing can and misalignment tolerance is only 3–4 arc-minutes.
- Never press either ring through the roller complement when fitting: mounting force goes through the ring faces, or the 230 mm race brinells and releases as vibration within hours.
- Open NU226 units need application-supplied sealing and a defined lubricant schedule; film thickness is the first failure mode for line contact when viscosity drops at the 130 mm contact.
- The 300/340 kN ratings, 35 kN Pu and 6170 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NU226 (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 NU226?
NU226 is an NTN NU single-row cylindrical roller bearing to ISO 15: 130 mm bore, 230 mm OD and 40 mm width (5.118 × 9.055 × 1.575 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 300 kN, C0 340 kN, Pu 35 kN, grease limiting speed 2,900 r/min, oil 3,400 r/min, mass about 6170 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. NU226 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. NU226 is supplied in the standard open execution shown in the table.
Can NU226 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 NU226?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 156 mm, Ew 204 mm. The nominal bore/OD remain 130/230 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 2,900 r/min grease / 3,400 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.