NU1068 bearing: complete specifications & equivalents
The NU1068 is a ISO 15 radial bearing sized 340 x 520 x 82 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 340 mm |
| Outer diameter D | 520 mm |
| Width B | 82 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 1160 kN |
| Basic static load rating C0 | 1670 kN |
| Fatigue load limit Pu | 132 kN |
| Limiting speed (mechanical) | 1200 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 60800 g |
| Manufacturer designation | NTN NU1068 |
| 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 & NU1000-series range
| Bore d | 13.386 in |
|---|---|
| Outer diameter D | 20.472 in |
| Width B | 3.228 in |
| ISO bore code | 68 |
| Radial section height (D−d)/2 | 90 mm |
| Smallest bore in NU1000-series | 25 mm |
| Largest outer diameter in NU1000-series | 1090 mm |
| Width range across NU1000-series | 12–150 mm |
| Bore position in NU1000-series (smallest first) | 34 of 47 |
| Bore above smallest NU1000-series size | 315 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NU1068 | 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 NU1068 model number is decoded
The NTN order number NU1068 denotes a 340×520×82 mm (13.386 × 20.472 × 3.228 in) cylindrical roller bearing in the NU1000 family, a pressed sheet-steel cage. On the NTN nameplate NU states which ring carries the ribs, which determines whether NU1068 floats or locates; the numeric remainder is the ISO 15 series and 340 mm bore reference, not a fit or clearance instruction. The 82 mm width and 90.0 mm section put the NU1000 series in the extra-light (10/49) section; wide 22/23 variants at the same bore change OD, width and heat generation and are not drop-in swaps. Thermal planning around the 1,200 r/min grease ceiling should include the cage type (a pressed sheet-steel cage) and oil-flow option to 1,400 r/min for continuously high-duty 340 mm positions. Heat the inner ring to max 120 °C for the 340 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
- heavy press and large gearbox main shafts
- rolling-mill work-roll and backup-roll positions
- large turbine and generator rotor bearings
- wind-turbine gearbox planet and rotor shafts
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
- micro-pitting when the EHL film falls below the composite roughness at high specific load
- edge loading from shaft deflection beyond the 3–4 arc-minute alignment limit
- fretting corrosion on a loose rotating shaft seat
Selection pitfalls — read before you substitute
- At 340 mm bore, oil-lubricated arrangements toward 1,400 r/min need positive flow and drain design; the 60800 g NU1068 ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- If the shaft must be located both ways, do not use NU1068 alone: pair it with a locating bearing or specify the NUP execution with the matching loose rib ring from the 2203E table.
- Minimum radial load is frequently missed in oversized motor and fan selections: an underloaded NU1068 skids at 1,200 r/min and fails by smearing long before L10 fatigue.
- The NU rib arrangement is not interchangeable with another prefix on the same 340 mm seat: outer ring ribbed, inner ring ribless. Swapping NU for NJ changes axial location behaviour even though the 520×82 mm envelope matches.
- Open NU1068 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 340 mm contact.
- The 1160/1670 kN ratings, 132 kN Pu and 60800 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NU1068 (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 NU1068?
NU1068 is an NTN NU single-row cylindrical roller bearing to ISO 15: 340 mm bore, 520 mm OD and 82 mm width (13.386 × 20.472 × 3.228 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 1160 kN, C0 1670 kN, Pu 132 kN, grease limiting speed 1,200 r/min, oil 1,400 r/min, mass about 60800 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. NU1068 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. NU1068 is supplied in the standard open execution shown in the table.
Can NU1068 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 NU1068?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 385 mm, Ew 475 mm. The nominal bore/OD remain 340/520 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 1,200 r/min grease / 1,400 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.