32315U bearing: complete specifications & equivalents
The 32315U is a ISO 355 radial bearing sized 75 x 160 x 58 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 75 mm |
| Outer diameter D | 160 mm |
| Width B | 58 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 395 kN |
| Basic static load rating C0 | 470 kN |
| Fatigue load limit Pu | 54.5 kN |
| Limiting speed (mechanical) | 2400 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 5400 g |
| Manufacturer designation | NTN 32315U |
| Standard | ISO 355 |
| 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 & 32300-series range
| Bore d | 2.953 in |
|---|---|
| Outer diameter D | 6.299 in |
| Width B | 2.283 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 42.5 mm |
| Smallest bore in 32300-series | 20 mm |
| Largest outer diameter in 32300-series | 460 mm |
| Width range across 32300-series | 22.25–154 mm |
| Bore position in 32300-series (smallest first) | 13 of 30 |
| Bore above smallest 32300-series size | 55 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 32315U | 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 32315U model number is decoded
For a 75 mm shaft with a thrust component, NTN lists 32315U, a metric 4T tapered roller bearing of 395 kN C and 470 kN C0 inside the 160 mm OD, 58 mm-wide assembled set. NTN also quotes this bearing with its ISO 355 dimension-series abbreviation, 2GD, which is the maker-neutral cross-reference for the 75×160 mm envelope; 4T is NTN's own tapered-roller brand mark on the parts. The pressed-steel cage and surface-finished roller ends are standard 4T execution; ULTAGE-marked variants use upgraded material and internal geometry aimed at longer rating life with the same ISO 355 envelope. Selection: C 395 kN against C0 470 kN gives a C0/C ratio of 1.19 for the 75 mm bore, and the equivalent combined load must keep below the rating at the target L10 with the pair counted as one unit. Open 4T bearings need application seals; without them the grease at the cone rib of 32315U washes out and the rib/roller-end contact smears on the first wet or dusty shift.
Typical equipment & failure modes
Common applications
- heavy industrial gearboxes and crane travel drives
- rolling-mill auxiliary and pinion-stand shafts
- large conveyor and bucket-elevator pulleys
- mineral-processing feeder and crusher auxiliaries
Known failure patterns
- cone-raceway spalling at the large rib when preload is set too high for the lubricant film
- flaking on one cone only when a back-to-back / face-to-face pair is loaded unevenly by a bent shaft
- smearing on the roller large ends and cone rib after a dry start with preload but no oil film
- pressed-steel cage pocket wear from roller skid at light radial load and high speed
- brinell marks on cone and cup raceways from impact during handling or hammering during fitting
Selection pitfalls — read before you substitute
- Mount the 75 mm cone by induction heating (max 120 °C) and the cup with a press sleeve; the 5400 g ring mass makes cocking during fitting a direct raceway-brinelling risk.
- The extra-heavy 32300 family at 75 mm bore (160×58 mm assembled) carries more capacity than the lighter 320/329 sections but generates more preload heat; confirm oil availability before running near the 3,200 r/min oil ceiling.
- Back-to-back and face-to-face arrangements react differently to shaft bending: pick the pair orientation for the moment load before locking the 75 mm shoulder geometry, because retrofitting flips the cups.
- Back-to-back and face-to-face arrangements react differently to shaft bending: pick the pair orientation for the moment load before locking the 75 mm shoulder geometry, because retrofitting flips the cups.
- Replacing one half of an adjusted pair without resetting end play negates the 58 mm T dimension logic: re-adjust the set and re-verify the contact pattern rather than reusing the old spacer stack.
- The 395/470 kN ratings and 54.5 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 32315U (ISO 355 2GD); internal geometry legitimately differs between manufacturers, so re-verify ratings, adjustment and suffix before substituting another make on a rated drive.
Frequently asked questions
What are the dimensions and catalogue ratings of NTN 32315U?
32315U is a metric 4T tapered roller bearing to ISO 355: 75 mm bore, 160 mm outside diameter and 58 mm assembled width T (2.953 × 6.299 × 2.283 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 395 kN, C0 470 kN, Pu 54.5 kN, grease limiting speed 2,400 r/min, oil speed 3,200 r/min, mass about 5400 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 32315U?
4T is NTN's tapered roller bearing brand mark, stamped on the cone and cup in the factory. It identifies the NTN 4T programme and is not a dimension, so the catalogue and this page list the bare ISO 355 number (32315U); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 32315U designation encode the 75 mm bore and what is 2GD?
last two digits 15 are the ISO bore code, ×5 = 75 mm (codes 00–03 use the 10/12/15/17 exception table). The 160 mm OD and 58 mm assembled T follow the ISO 355 dimension-series plan. 2GD is the maker-neutral ISO 355 abbreviation for this dimension series (the same code other manufacturers print); 4T is NTN's own brand mark.
Why does 32315U list two speeds, 2,400 and 3,200 r/min?
The lower figure, 2,400 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 32315U at 3,200 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 32315U mean?
Suffix reading on 32315U: U marks the reinforced/uprated internal design of the bare number, a separate order number with higher load capacity than the basic execution; the suffix is part of the order number and the variants are not interchangeable articles.
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.