NU1028 bearing: complete specifications & equivalents
The NU1028 is a ISO 15 radial bearing sized 140 x 210 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 | 140 mm |
| Outer diameter D | 210 mm |
| Width B | 33 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 195 kN |
| Basic static load rating C0 | 250 kN |
| Fatigue load limit Pu | 25.7 kN |
| Limiting speed (mechanical) | 3200 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 3980 g |
| Manufacturer designation | NTN NU1028 |
| 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 | 5.512 in |
|---|---|
| Outer diameter D | 8.268 in |
| Width B | 1.299 in |
| ISO bore code | 28 |
| Radial section height (D−d)/2 | 35 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) | 21 of 47 |
| Bore above smallest NU1000-series size | 115 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NU1028-ML | SKF | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
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 NU1028 model number is decoded
NU1028 is an NTN NU 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 140×210×33 mm ISO 15 envelope. Reading the code: NU for the non-locating separable-inner-ring type, then the ISO 15 diameter/width series and the bore code — ×5 = 140 mm (00–03 use the 10/12/15/17 exception table). NTN ships these bearings open with normal (CN) radial clearance and P0 tolerance as standard; precision classes and C3/C4 clearance are separate order suffixes, not part of NU1028. Speed ratio check: limiting 3,200 r/min is .84 of the 3,800 r/min oil value for NU1028; grease-churn heating closes that gap as fill quantity rises. Mount the separable inner ring + roller assembly on the shaft first and slide the outer ring into the housing; never press the outer ring through the rollers of NU1028.
Typical equipment & failure modes
Common applications
- wind-turbine gearbox planet and rotor shafts
- ship propulsion line shafts and reduction gears
- mining SAG/ball-mill drive shafts
- offshore drawworks and winch drums
Known failure patterns
- roller smearing (microwelding) at start-up before the oil film builds under insufficient radial load
- pressed-steel cage pocket wear when rollers skid at light load or too-thin lubricant
- roller-end and raceway scoring from inadequate oil flow under heavy radial load
- false brinelling on standby machines exposed to external vibration
- electrical pitting on VFD-driven motor shafts without grounding protection
Selection pitfalls — read before you substitute
- At 140 mm bore, oil-lubricated arrangements toward 3,800 r/min need positive flow and drain design; the 3980 g NU1028 ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- The 35.0 mm section at 140 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 33 mm-wide cavity.
- Grease limiting speed 3,200 r/min and oil 3,800 r/min are different limits for NU1028: the first is the cage/lubricant mechanical ceiling, the second assumes real oil flow rather than an oil bath.
- Open NU1028 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 140 mm contact.
- Never press either ring through the roller complement when fitting: mounting force goes through the ring faces, or the 210 mm race brinells and releases as vibration within hours.
- The 195/250 kN ratings, 25.7 kN Pu and 3980 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NU1028 (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 NU1028?
NU1028 is an NTN NU single-row cylindrical roller bearing to ISO 15: 140 mm bore, 210 mm OD and 33 mm width (5.512 × 8.268 × 1.299 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 195 kN, C0 250 kN, Pu 25.7 kN, grease limiting speed 3,200 r/min, oil 3,800 r/min, mass about 3980 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. NU1028 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. NU1028 is supplied in the standard open execution shown in the table.
Can NU1028 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 NU1028?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 158 mm, Ew 192 mm. The nominal bore/OD remain 140/210 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 3,200 r/min grease / 3,800 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.