NUP338 bearing: complete specifications & equivalents
The NUP338 is a ISO 15 radial bearing sized 190 x 400 x 78 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 190 mm |
| Outer diameter D | 400 mm |
| Width B | 78 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 1080 kN |
| Basic static load rating C0 | 1260 kN |
| Fatigue load limit Pu | 111 kN |
| Limiting speed (mechanical) | 1600 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 48300 g |
| Manufacturer designation | NTN NUP338 |
| 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 & NUP300-series range
| Bore d | 7.48 in |
|---|---|
| Outer diameter D | 15.748 in |
| Width B | 3.071 in |
| ISO bore code | 38 |
| Radial section height (D−d)/2 | 105 mm |
| Smallest bore in NUP300-series | 20 mm |
| Largest outer diameter in NUP300-series | 580 mm |
| Width range across NUP300-series | 15–108 mm |
| Bore position in NUP300-series (smallest first) | 27 of 32 |
| Bore above smallest NUP300-series size | 170 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NUP338 | 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 NUP338 model number is decoded
NUP338 is the standard section of the NTN NUP300 dimension series for a 190 mm shaft — 1080 kN of basic dynamic capacity in a 48300 g, open bearing. On the NTN nameplate NUP states which ring carries the ribs, which determines whether NUP338 floats or locates; the numeric remainder is the ISO 15 series and 190 mm bore reference, not a fit or clearance instruction. 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 NUP338. Speed ratio check: limiting 1,600 r/min is .84 of the 1,900 r/min oil value for NUP338; grease-churn heating closes that gap as fill quantity rises. Confirm the loose L-shaped rib ring is fitted and seated, since it is what turns the NJ-type arrangement into the two-direction-locating NUP set on the 190 mm shaft.
Typical equipment & failure modes
Common applications
- offshore drawworks and winch drums
- heavy press and large gearbox main shafts
- rolling-mill work-roll and backup-roll positions
- large turbine and generator rotor bearings
Known failure patterns
- inner-ring raceway spalling from overload in the line-contact Hertzian zone
- cage wear accelerated when the EA high-capacity roller complement runs continuously above its thermal balance
- micro-pitting when the EHL film falls below the composite roughness at high specific load
- electrical pitting on VFD-driven motor shafts without grounding protection
- fretting corrosion on a loose rotating shaft seat
Selection pitfalls — read before you substitute
- At 190 mm bore, oil-lubricated arrangements toward 1,900 r/min need positive flow and drain design; the 48300 g NUP338 ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- Never press either ring through the roller complement when fitting: mounting force goes through the ring faces, or the 400 mm race brinells and releases as vibration within hours.
- Wide (22/23) and light (10/49) executions at 190 mm bore share bore but not OD/width; check the full NUP300 series code before substituting, because housing and shoulder geometry will not interchange.
- The NUP rib arrangement is not interchangeable with another prefix on the same 190 mm seat: inner ring two ribs + loose L-ring. Swapping NU for NJ changes axial location behaviour even though the 400×78 mm envelope matches.
- Never press either ring through the roller complement when fitting: mounting force goes through the ring faces, or the 400 mm race brinells and releases as vibration within hours.
- The 1080/1260 kN ratings, 111 kN Pu and 48300 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NUP338 (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 NUP338?
NUP338 is an NTN NUP single-row cylindrical roller bearing to ISO 15: 190 mm bore, 400 mm OD and 78 mm width (7.48 × 15.748 × 3.071 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 1080 kN, C0 1260 kN, Pu 111 kN, grease limiting speed 1,600 r/min, oil 1,900 r/min, mass about 48300 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. NUP338 is the NJ rib arrangement plus a loose L-shaped rib ring on the inner ring — it locates the shaft in both axial directions.
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. NUP338 is supplied in the standard open execution shown in the table.
Can NUP338 take axial load and locate a shaft?
the NUP design provides two-direction axial location via its loose rib ring, for light/moderate thrust guidance. The loose rib ring still only suits light/short-duration axial guidance; heavy thrust belongs to a dedicated thrust bearing.
What do Fw and Ew mean for NUP338?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 245 mm, Ew 345 mm. The nominal bore/OD remain 190/400 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 1,600 r/min grease / 1,900 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.