NN4952 bearing: complete specifications & equivalents
The NN4952 is a ISO 15 radial bearing sized 260 x 360 x 100 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 260 mm |
| Outer diameter D | 360 mm |
| Width B | 100 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 1000 kN |
| Basic static load rating C0 | 2070 kN |
| Fatigue load limit Pu | 179 kN |
| Limiting speed (mechanical) | 1600 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 28300 g |
| Manufacturer designation | NTN NN4952 |
| 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 | 10.236 in |
|---|---|
| Outer diameter D | 14.173 in |
| Width B | 3.937 in |
| ISO bore code | 52 |
| Radial section height (D−d)/2 | 50 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) | 15 of 18 |
| Bore above smallest NN4900-series size | 160 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NN4952 | 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 NN4952 model number is decoded
NN4952 is an NTN NN cylindrical roller bearing: two integral ribs on the outer ring and a ribless, separable inner ring — a non-locating bearing that lets the shaft float axially, inside the 260×360×100 mm ISO 15 envelope. On the NTN nameplate NN states which ring carries the ribs, which determines whether NN4952 floats or locates; the numeric remainder is the ISO 15 series and 260 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. With the inner ring rotating, catalogue practice is a m6/n6 shaft seat and an H7/H6 housing; the outer ring must remain free to creep slightly axially in non-locating NN arrangements. Housing and shaft fillets must clear the ring chamfers of NN4952; an oversized radius locks the ring on its face and tilts the 100 mm-wide seat.
Typical equipment & failure modes
Common applications
- high-rpm motorised grinding and milling spindles
- CNC lathe and machining-centre spindle radial sets
- precision rotary-table and dividing-head bearings
- high-speed turbine and turbo-blower rotor supports
Known failure patterns
- roller smearing (microwelding) at start-up before the oil film builds under insufficient radial load
- 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
- edge loading from shaft deflection beyond the 3–4 arc-minute alignment limit
- edge loading from shaft deflection beyond the 3–4 arc-minute alignment limit
Selection pitfalls — read before you substitute
- At 260 mm bore, oil-lubricated arrangements toward 1,800 r/min need positive flow and drain design; the 28300 g NN4952 ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- Grease limiting speed 1,600 r/min and oil 1,800 r/min are different limits for NN4952: the first is the cage/lubricant mechanical ceiling, the second assumes real oil flow rather than an oil bath.
- The 50.0 mm section at 260 mm bore leaves a narrow oil path; with the standard cage the relubrication groove and oil-level design must keep grease from churning in the 100 mm-wide cavity.
- The NN rib arrangement is not interchangeable with another prefix on the same 260 mm seat: double row, ribbed inner ring, separable outer. Swapping NU for NJ changes axial location behaviour even though the 360×100 mm envelope matches.
- The 100 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 260 mm inner ring.
- The 1000/2070 kN ratings, 179 kN Pu and 28300 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NN4952 (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 NN4952?
NN4952 is an NTN NN double-row precision cylindrical roller bearing to ISO 15: 260 mm bore, 360 mm OD and 100 mm width (10.236 × 14.173 × 3.937 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 1000 kN, C0 2070 kN, Pu 179 kN, grease limiting speed 1,600 r/min, oil 1,800 r/min, mass about 28300 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. NN4952 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. NN4952 is supplied in the standard open execution shown in the table.
What does the K tapered bore mean on a precision NN bearing like NN4952?
NN4952 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 NN4952?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 292 mm. The nominal bore/OD remain 260/360 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 1,600 r/min grease / 1,800 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.