NF334 bearing: complete specifications & equivalents
The NF334 is a ISO 15 radial bearing sized 170 x 360 x 72 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 170 mm |
| Outer diameter D | 360 mm |
| Width B | 72 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 885 kN |
| Basic static load rating C0 | 1010 kN |
| Fatigue load limit Pu | 92 kN |
| Limiting speed (mechanical) | 1800 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 36100 g |
| Manufacturer designation | NTN NF334 |
| 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 | 6.693 in |
|---|---|
| Outer diameter D | 14.173 in |
| Width B | 2.835 in |
| ISO bore code | 34 |
| Radial section height (D−d)/2 | 95 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) | 25 of 32 |
| Bore above smallest NF300-series size | 150 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NF334 | 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 NF334 model number is decoded
For pure radial duty on a 170 mm shaft NTN supplies NF334: one integral rib on each ring; the open execution is rated 1,800 r/min on grease and 2,200 r/min on oil. Reading the code: NF for the rib-on-each-ring type, then the ISO 15 diameter/width series and the bore code — ×5 = 170 mm (00–03 use the 10/12/15/17 exception table). At 2,200 r/min with oil versus 1,800 r/min with grease (a 400 r/min band), lubrication choice for NF334 is a thermal decision, not just a sealing one. Selection arithmetic: Pu 92 kN is the fatigue load limit feeding the adjusted-life equation, and the C0/C ratio of 1.14 (1010/885 kN) shows the high-static-capacity proportioning of this 170 mm bore. Keep the open bearing wrapped until fitting: the line-contact raceways of the 170 mm bore indent under a single hard particle, and the steel cage provides no sealing of its own.
Typical equipment & failure modes
Common applications
- rolling-mill work-roll and backup-roll positions
- large turbine and generator rotor bearings
- wind-turbine gearbox planet and rotor shafts
- ship propulsion line shafts and reduction gears
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
- grease starvation and cage drag when relubrication intervals are extended past the grease life
- fretting corrosion on a loose rotating shaft seat
- brinelling from static overload or impact during handling
Selection pitfalls — read before you substitute
- At 170 mm bore, oil-lubricated arrangements toward 2,200 r/min need positive flow and drain design; the 36100 g NF334 ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- The 72 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 170 mm inner ring.
- Wide (22/23) and light (10/49) executions at 170 mm bore share bore but not OD/width; check the full NF300 series code before substituting, because housing and shoulder geometry will not interchange.
- Open NF334 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 170 mm contact.
- Grease limiting speed 1,800 r/min and oil 2,200 r/min are different limits for NF334: the first is the cage/lubricant mechanical ceiling, the second assumes real oil flow rather than an oil bath.
- The 885/1010 kN ratings, 92 kN Pu and 36100 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NF334 (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 NF334?
NF334 is an NTN NF single-row cylindrical roller bearing to ISO 15: 170 mm bore, 360 mm OD and 72 mm width (6.693 × 14.173 × 2.835 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 885 kN, C0 1010 kN, Pu 92 kN, grease limiting speed 1,800 r/min, oil 2,200 r/min, mass about 36100 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. NF334 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. NF334 is supplied in the standard open execution shown in the table.
Can NF334 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 NF334?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 220 mm, Ew 310 mm. The nominal bore/OD remain 170/360 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 1,800 r/min grease / 2,200 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.