NN4926K bearing: complete specifications & equivalents
The NN4926K is a ISO 15 radial bearing sized 130 x 180 x 50 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 | 180 mm |
| Width B | 50 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 244 kN |
| Basic static load rating C0 | 440 kN |
| Fatigue load limit Pu | 47 kN |
| Limiting speed (mechanical) | 3300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 3350 g |
| Manufacturer designation | NTN NN4926K |
| 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 & NN4900-series range
| Bore d | 5.118 in |
|---|---|
| Outer diameter D | 7.087 in |
| Width B | 1.969 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 25 mm |
| Smallest bore in NN4900-series | 100 mm |
| Largest outer diameter in NN4900-series | 440 mm |
| Width range across NN4900-series | 40–118 mm |
| Bore position in NN4900-series (smallest first) | 5 of 18 |
| Bore above smallest NN4900-series size | 30 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NN4926K | 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 NN4926K model number is decoded
The NTN order number NN4926K denotes a 130×180×50 mm (5.118 × 7.087 × 1.969 in) cylindrical roller bearing in the NN4900 family, a machined or stamped steel cage per the precision execution. Digit by digit, NN4926K reads as NN (double row, ribbed inner ring, separable outer), ISO 15 series, and bore 130 mm; trailing letters such as EA or E mark the cage/capacity execution and are part of the order number. NTN ships these bearings open with normal (CN) radial clearance and P0 tolerance as standard; precision classes and C3/C4 clearance are separate order suffixes, not part of NN4926K. The 130 mm (5.118 in) bore and 180 mm (7.087 in) OD are ISO 15 boundary values; fillet and shoulder dimensions must still come from the NTN mounting table for the 50 mm-wide ring. 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 NN4926K.
Typical equipment & failure modes
Common applications
- CNC lathe and machining-centre spindle radial sets
- precision rotary-table and dividing-head bearings
- high-speed turbine and turbo-blower rotor supports
- coordinate-measuring and semiconductor-equipment drives
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
- fretting corrosion on a loose rotating shaft seat
- brinelling from static overload or impact during handling
Selection pitfalls — read before you substitute
- At 130 mm bore, oil-lubricated arrangements toward 3,900 r/min need positive flow and drain design; the 3350 g NN4926K ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- Open NN4926K 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.
- Open NN4926K 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 50 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 130 mm inner ring.
- Never press either ring through the roller complement when fitting: mounting force goes through the ring faces, or the 180 mm race brinells and releases as vibration within hours.
- The 244/440 kN ratings, 47 kN Pu and 3350 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NN4926K (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 NN4926K?
NN4926K is an NTN NN double-row precision cylindrical roller bearing to ISO 15: 130 mm bore, 180 mm OD and 50 mm width (5.118 × 7.087 × 1.969 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 244 kN, C0 440 kN, Pu 47 kN, grease limiting speed 3,300 r/min, oil 3,900 r/min, mass about 3350 g. It is open, with a machined or stamped steel cage per the precision execution.
What is the difference between NU, NJ, NUP, N and NF cylindrical roller bearings?
NN and NNU are double-row precision designs rather than single-row rib variants: NN has a ribbed inner ring and separable outer ring, NNU the reverse; both give high radial stiffness for spindles and are commonly ordered with P5/P4 precision and a K 1:12 tapered bore for preload setting. NN4926K is the NN execution.
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. NN4926K is supplied in the standard open execution shown in the table.
What does the K tapered bore mean on a precision NN bearing like NN4926K?
The K suffix denotes a 1:12 tapered bore. NN4926K mounts on a tapered shaft seat or adapter sleeve and is driven up to a measured residual clearance or preload — this is how precision spindle bearings achieve stiffness without locknut guesswork; the cylindrical-bore NN4926 execution of the same envelope mounts on a plain seat.
What do Fw and Ew mean for NN4926K?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 146 mm. The nominal bore/OD remain 130/180 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 3,300 r/min grease / 3,900 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.