NN4936 bearing: complete specifications & equivalents
The NN4936 is a ISO 15 radial bearing sized 180 x 250 x 69 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 180 mm |
| Outer diameter D | 250 mm |
| Width B | 69 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 510 kN |
| Basic static load rating C0 | 965 kN |
| Fatigue load limit Pu | 93 kN |
| Limiting speed (mechanical) | 2300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 9450 g |
| Manufacturer designation | NTN NN4936 |
| 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 | 7.087 in |
|---|---|
| Outer diameter D | 9.843 in |
| Width B | 2.717 in |
| ISO bore code | 36 |
| Radial section height (D−d)/2 | 35 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) | 10 of 18 |
| Bore above smallest NN4900-series size | 80 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NN4936 | 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 NN4936 model number is decoded
The NTN order number NN4936 denotes a 180×250×69 mm (7.087 × 9.843 × 2.717 in) cylindrical roller bearing in the NN4900 family, a machined or stamped steel cage per the precision execution. On the NTN nameplate NN states which ring carries the ribs, which determines whether NN4936 floats or locates; the numeric remainder is the ISO 15 series and 180 mm bore reference, not a fit or clearance instruction. Double-row NN precision cylindrical roller bearing: ribbed inner ring with a separable outer ring, two roller rows for high radial stiffness on machine-tool spindles; precision classes P5/P4/P2 and clearance are ordered separately. The 2.8 kN-per-mm-bore figure (510 kN over 180 mm) lets a NN4936 interchange candidate be screened quickly against the same-envelope ball or roller alternatives. After mounting verify the outer ring slides axially by hand at ambient temperature; a stuck float ring in a NN4936 non-locating position preloads the bearing when the shaft grows.
Typical equipment & failure modes
Common applications
- precision gearbox and indexing-drive shafts
- high-rpm motorised grinding and milling spindles
- CNC lathe and machining-centre spindle radial sets
- precision rotary-table and dividing-head bearings
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
- false brinelling on standby machines exposed to external vibration
- fretting corrosion on a loose rotating shaft seat
Selection pitfalls — read before you substitute
- At 180 mm bore, oil-lubricated arrangements toward 2,700 r/min need positive flow and drain design; the 9450 g NN4936 ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- Minimum radial load is frequently missed in oversized motor and fan selections: an underloaded NN4936 skids at 2,300 r/min and fails by smearing long before L10 fatigue.
- Wide (22/23) and light (10/49) executions at 180 mm bore share bore but not OD/width; check the full NN4900 series code before substituting, because housing and shoulder geometry will not interchange.
- The 69 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 180 mm inner ring.
- The 69 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 180 mm inner ring.
- The 510/965 kN ratings, 93 kN Pu and 9450 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NN4936 (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 NN4936?
NN4936 is an NTN NN double-row precision cylindrical roller bearing to ISO 15: 180 mm bore, 250 mm OD and 69 mm width (7.087 × 9.843 × 2.717 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 510 kN, C0 965 kN, Pu 93 kN, grease limiting speed 2,300 r/min, oil 2,700 r/min, mass about 9450 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. NN4936 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. NN4936 is supplied in the standard open execution shown in the table.
What does the K tapered bore mean on a precision NN bearing like NN4936?
NN4936 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 NN4936?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 202 mm. The nominal bore/OD remain 180/250 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 2,300 r/min grease / 2,700 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.