NN4926 bearing: complete specifications & equivalents
The NN4926 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 | 3520 g |
| Manufacturer designation | NTN NN4926 |
| 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 | 26 |
| 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 |
|---|---|---|---|
| NN4926 | 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 NN4926 model number is decoded
NTN lists NN4926 on the 130×180 mm envelope, 50 mm wide: a line-contact radial bearing with a machined or stamped steel cage per the precision execution and a grease limiting speed of 3,300 r/min. The leading NN defines the rib arrangement (double row, ribbed inner ring, separable outer); the dimension-series digits and the two-digit bore code resolve to 130 mm, with 180 mm OD and 50 mm width from the ISO 15 general plan. 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 NN4926. Mass 3520 g for the 130×180×50 mm NN4926 execution covers the pressed-steel cage and full roller complement; substitute on mass plus rating, not envelope alone. Housing and shaft fillets must clear the ring chamfers of NN4926; an oversized radius locks the ring on its face and tilts the 50 mm-wide seat.
Typical equipment & failure modes
Common applications
- machine-tool main spindles requiring high radial stiffness
- precision gearbox and indexing-drive shafts
- high-rpm motorised grinding and milling spindles
- CNC lathe and machining-centre spindle radial sets
Known failure patterns
- inner-ring raceway spalling from overload in the line-contact Hertzian zone
- pressed-steel cage pocket wear when rollers skid at light load or too-thin lubricant
- micro-pitting when the EHL film falls below the composite roughness at high specific load
- hard-particle indentation of raceways in unfiltered oil or open arrangements
- edge loading from shaft deflection beyond the 3–4 arc-minute alignment limit
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 3520 g NN4926 ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- The NN rib arrangement is not interchangeable with another prefix on the same 130 mm seat: double row, ribbed inner ring, separable outer. Swapping NU for NJ changes axial location behaviour even though the 180×50 mm envelope matches.
- Double-row NN precision bearings are typically ordered P5/P4 with specific radial clearance for spindle preloading; a P0/CN NN4926 does not substitute a precision-class execution.
- Wide (22/23) and light (10/49) executions at 130 mm bore share bore but not OD/width; check the full NN4900 series code before substituting, because housing and shoulder geometry will not interchange.
- 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 3520 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NN4926 (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 NN4926?
NN4926 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 3520 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. NN4926 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. NN4926 is supplied in the standard open execution shown in the table.
What does the K tapered bore mean on a precision NN bearing like NN4926?
NN4926 has a cylindrical bore and mounts on a plain machined shaft seat; a K execution (1:12 taper) exists in the NN4900 series when preload must be set by drive-up on a tapered seat.
What do Fw and Ew mean for NN4926?
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.