NU310-NTN bearing: complete specifications & equivalents
The NU310-NTN is a ISO 15 radial bearing sized 50 x 110 x 27 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 50 mm |
| Outer diameter D | 110 mm |
| Width B | 27 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 96.5 kN |
| Basic static load rating C0 | 86 kN |
| Fatigue load limit Pu | 10.5 kN |
| Limiting speed (mechanical) | 6500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1110 g |
| Manufacturer designation | NTN NU310 |
| 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 & NU300-series range
| Bore d | 1.969 in |
|---|---|
| Outer diameter D | 4.331 in |
| Width B | 1.063 in |
| ISO bore code | 10 |
| Radial section height (D−d)/2 | 30 mm |
| Smallest bore in NU300-series | 17 mm |
| Largest outer diameter in NU300-series | 620 mm |
| Width range across NU300-series | 14–109 mm |
| Bore position in NU300-series (smallest first) | 8 of 34 |
| Bore above smallest NU300-series size | 33 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NU310 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 50×110×27 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
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 NU310-NTN model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, NU310 appears as a 50 mm bore single-row cylindrical roller bearing (96.5 kN C / 86 kN C0) with a pressed sheet-steel cage, listed to the ISO 15 boundary plan. Numbering ties NU310 to its envelope: type code NU, series NU300, 50 mm bore; the 110×27 mm outline therefore swaps dimensionally with other ISO 15 bearings of the same code, though rib arrangements differ by prefix. NTN prints two speed ceilings: 6,500 r/min grease and 7,700 r/min oil — the pressed-steel cage and lubricant film set the real limit at the 50 mm bore. The 50 mm (1.969 in) bore and 110 mm (4.331 in) OD are ISO 15 boundary values; fillet and shoulder dimensions must still come from the NTN mounting table for the 27 mm-wide ring. After mounting verify the outer ring slides axially by hand at ambient temperature; a stuck float ring in a NU310 non-locating position preloads the bearing when the shaft grows.
Typical equipment & failure modes
Common applications
- fan and blower rotor positions
- industrial gearbox input and output shafts
- medium electric-motor and generator shafts
- pump and compressor crankshafts and rotors
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
- grease starvation and cage drag when relubrication intervals are extended past the grease life
- brinelling from static overload or impact during handling
- brinelling from static overload or impact during handling
Selection pitfalls — read before you substitute
- On this 50 mm bore, shaft thermal growth can preload the inner ring if the fit is too tight; verify residual interference at temperature and confirm the float ring still slides after mounting NU310.
- If the shaft must be located both ways, do not use NU310 alone: pair it with a locating bearing or specify the NUP execution with the matching loose rib ring from the 2203E table.
- The 30.0 mm section at 50 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 27 mm-wide cavity.
- The 27 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 50 mm inner ring.
- If the shaft must be located both ways, do not use NU310 alone: pair it with a locating bearing or specify the NUP execution with the matching loose rib ring from the 2203E table.
- The 96.5/86 kN ratings, 10.5 kN Pu and 1110 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NU310 (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 NU310?
NU310 is an NTN NU single-row cylindrical roller bearing to ISO 15: 50 mm bore, 110 mm OD and 27 mm width (1.969 × 4.331 × 1.063 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 96.5 kN, C0 86 kN, Pu 10.5 kN, grease limiting speed 6,500 r/min, oil 7,700 r/min, mass about 1110 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. NU310 is two integral ribs on the outer ring and a ribless, separable inner ring — a non-locating bearing that lets the shaft float axially.
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. NU310 is listed among the ＊ ULTAGE-marked executions in 2203E.
Can NU310 take axial load and locate a shaft?
the NU design carries no axial load and floats axially on both sides. Provide axial location with an adjacent locating bearing (angular-contact, deep-groove or a paired NJ/NUP set).
What do Fw and Ew mean for NU310?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 65 mm, Ew 95 mm. The nominal bore/OD remain 50/110 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 6,500 r/min grease / 7,700 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.