NU313-NTN bearing: complete specifications & equivalents
The NU313-NTN is a ISO 15 radial bearing sized 65 x 140 x 33 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 65 mm |
| Outer diameter D | 140 mm |
| Width B | 33 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 150 kN |
| Basic static load rating C0 | 139 kN |
| Fatigue load limit Pu | 16.8 kN |
| Limiting speed (mechanical) | 5100 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2180 g |
| Manufacturer designation | NTN NU313 |
| 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 | 2.559 in |
|---|---|
| Outer diameter D | 5.512 in |
| Width B | 1.299 in |
| ISO bore code | 13 |
| Radial section height (D−d)/2 | 37.5 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) | 11 of 34 |
| Bore above smallest NU300-series size | 48 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NU313 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 65×140×33 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 NU313-NTN model number is decoded
NTN lists NU313 on the 65×140 mm envelope, 33 mm wide: a line-contact radial bearing with a pressed sheet-steel cage and a grease limiting speed of 5,100 r/min. Reading the code: NU for the non-locating separable-inner-ring type, then the ISO 15 diameter/width series and the bore code — ×5 = 65 mm (00–03 use the 10/12/15/17 exception table). The 33 mm width and 37.5 mm section put the NU300 series in the standard section; wide 22/23 variants at the same bore change OD, width and heat generation and are not drop-in swaps. With the inner ring rotating, catalogue practice is a k5/m5 shaft seat and an H7/H6 housing; the outer ring must remain free to creep slightly axially in non-locating NU arrangements. Heat the inner ring to max 120 °C for the 65 mm interference fit and support the ring face square during fitting; cocking over a keyway brinells the raceway before first rotation.
Typical equipment & failure modes
Common applications
- large electric-motor and generator rotors
- cement and mining conveyor drive pulleys
- heavy industrial gearbox and reducer shafts
- large pump, turbine and compressor rotors
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
- grease starvation and cage drag when relubrication intervals are extended past the grease life
- electrical pitting on VFD-driven motor shafts without grounding protection
- hard-particle indentation of raceways in unfiltered oil or open arrangements
Selection pitfalls — read before you substitute
- Induction-heat the 65 mm inner ring (max 120 °C) and mount it before fitting the outer ring; the ring mass makes square guidance essential — driving through the rollers brinells the 140 mm raceway.
- The EA high-capacity roller complement changes the load figure versus the basic execution of the same number; the 150/139 kN pair here belongs to NU313 as printed, not to the bare size.
- Open NU313 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 65 mm contact.
- Minimum radial load is frequently missed in oversized motor and fan selections: an underloaded NU313 skids at 5,100 r/min and fails by smearing long before L10 fatigue.
- Open NU313 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 65 mm contact.
- The 150/139 kN ratings, 16.8 kN Pu and 2180 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NU313 (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 NU313?
NU313 is an NTN NU single-row cylindrical roller bearing to ISO 15: 65 mm bore, 140 mm OD and 33 mm width (2.559 × 5.512 × 1.299 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 150 kN, C0 139 kN, Pu 16.8 kN, grease limiting speed 5,100 r/min, oil 6,000 r/min, mass about 2180 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. NU313 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. NU313 is listed among the ＊ ULTAGE-marked executions in 2203E.
Can NU313 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 NU313?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 83.5 mm, Ew 121.5 mm. The nominal bore/OD remain 65/140 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 5,100 r/min grease / 6,000 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.