NF326 bearing: complete specifications & equivalents
The NF326 is a ISO 15 radial bearing sized 130 x 280 x 58 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 | 280 mm |
| Width B | 58 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 620 kN |
| Basic static load rating C0 | 665 kN |
| Fatigue load limit Pu | 65.5 kN |
| Limiting speed (mechanical) | 2500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 17000 g |
| Manufacturer designation | NTN NF326 |
| 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 & NF300-series range
| Bore d | 5.118 in |
|---|---|
| Outer diameter D | 11.024 in |
| Width B | 2.283 in |
| ISO bore code | 26 |
| Radial section height (D−d)/2 | 75 mm |
| Smallest bore in NF300-series | 20 mm |
| Largest outer diameter in NF300-series | 580 mm |
| Width range across NF300-series | 15–108 mm |
| Bore position in NF300-series (smallest first) | 21 of 32 |
| Bore above smallest NF300-series size | 110 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NF326 | 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 NF326 model number is decoded
NF326 is the standard section of the NTN NF300 dimension series for a 130 mm shaft — 620 kN of basic dynamic capacity in a 17000 g, open bearing. Reading the code: NF for the rib-on-each-ring type, then the ISO 15 diameter/width series and the bore code — ×5 = 130 mm (00–03 use the 10/12/15/17 exception table). At 2,900 r/min with oil versus 2,500 r/min with grease (a 400 r/min band), lubrication choice for NF326 is a thermal decision, not just a sealing one. Speed ratio check: limiting 2,500 r/min is .86 of the 2,900 r/min oil value for NF326; grease-churn heating closes that gap as fill quantity rises. 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 NF326.
Typical equipment & failure modes
Common applications
- ship propulsion line shafts and reduction gears
- mining SAG/ball-mill drive shafts
- offshore drawworks and winch drums
- heavy press and large gearbox main 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
- roller-end and raceway scoring from inadequate oil flow under heavy radial load
- brinelling from static overload or impact during handling
- false brinelling on standby machines exposed to external vibration
Selection pitfalls — read before you substitute
- At 130 mm bore, oil-lubricated arrangements toward 2,900 r/min need positive flow and drain design; the 17000 g NF326 ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- The EA high-capacity roller complement changes the load figure versus the basic execution of the same number; the 620/665 kN pair here belongs to NF326 as printed, not to the bare size.
- The NF rib arrangement is not interchangeable with another prefix on the same 130 mm seat: one rib on each ring. Swapping NU for NJ changes axial location behaviour even though the 280×58 mm envelope matches.
- Wide (22/23) and light (10/49) executions at 130 mm bore share bore but not OD/width; check the full NF300 series code before substituting, because housing and shoulder geometry will not interchange.
- Grease limiting speed 2,500 r/min and oil 2,900 r/min are different limits for NF326: the first is the cage/lubricant mechanical ceiling, the second assumes real oil flow rather than an oil bath.
- The 620/665 kN ratings, 65.5 kN Pu and 17000 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NF326 (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 NF326?
NF326 is an NTN NF single-row cylindrical roller bearing to ISO 15: 130 mm bore, 280 mm OD and 58 mm width (5.118 × 11.024 × 2.283 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 620 kN, C0 665 kN, Pu 65.5 kN, grease limiting speed 2,500 r/min, oil 2,900 r/min, mass about 17000 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. NF326 is one integral rib on each ring — separable inner ring with single-direction axial guidance and a defined shaft position.
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. NF326 is supplied in the standard open execution shown in the table.
Can NF326 take axial load and locate a shaft?
the NF design gives one-direction axial guidance via its single outer-ring rib. 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 NF326?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 167 mm, Ew 243 mm. The nominal bore/OD remain 130/280 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 2,500 r/min grease / 2,900 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.