32317U bearing: complete specifications & equivalents
The 32317U is a ISO 355 radial bearing sized 85 x 180 x 63.5 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 85 mm |
| Outer diameter D | 180 mm |
| Width B | 63.5 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 445 kN |
| Basic static load rating C0 | 525 kN |
| Fatigue load limit Pu | 59 kN |
| Limiting speed (mechanical) | 2100 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 7220 g |
| Manufacturer designation | NTN 32317U |
| 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 | 3.346 in |
|---|---|
| Outer diameter D | 7.087 in |
| Width B | 2.5 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 47.5 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) | 15 of 30 |
| Bore above smallest 32300-series size | 65 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 32317U | 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 32317U model number is decoded
The NTN 2203E table prints 32317U in the extra-heavy 32300 family: 85 mm bore, 180 mm cup OD, 63.5 mm T, with a grease limiting speed of 2,100 r/min and an oil-lubricated ceiling of 2,900 r/min. The last two digits 17 are the ISO bore code, ×5 = 85 mm (codes 00–03 use the 10/12/15/17 exception table) under the ISO 355 numbering; the 63.5 mm value printed here is T, the width of the fully assembled cone-plus-cup set, not the inner-ring width alone. The printed contact-angle geometry gives the extra-heavy 32300 family its characteristic load split — at 445/525 kN (C/C0) the static rating is about 1.18× C, typical of tapered bearings proportioned for heavy combined duty. The fatigue load limit Pu printed for 32317U is 59 kN; in the adjusted-life equation that is the equivalent-load floor below which high reliability is expected even under contamination. When pairing 32317U with a second tapered bearing, keep the matched arrangement clean: a single stray grit particle between cup and housing changes preload faster than the adjustment range can correct.
Typical equipment & failure modes
Common applications
- large conveyor and bucket-elevator pulleys
- mineral-processing feeder and crusher auxiliaries
- marine winch and deck-machinery shafts
- paper-machine press-section rolls
Known failure patterns
- cone-raceway spalling at the large rib when preload is set too high for the lubricant film
- smearing on the roller large ends and cone rib after a dry start with preload but no oil film
- flaking on one cone only when a back-to-back / face-to-face pair is loaded unevenly by a bent shaft
- cage damage from a mounting blow delivered through the roller complement instead of the ring face
- water-induced pitting when the open bearing is exposed to washdown without external seals
Selection pitfalls — read before you substitute
- Mount the 85 mm cone by induction heating (max 120 °C) and the cup with a press sleeve; the 7220 g ring mass makes cocking during fitting a direct raceway-brinelling risk.
- The extra-heavy 32300 family at 85 mm bore (180×63.5 mm assembled) carries more capacity than the lighter 320/329 sections but generates more preload heat; confirm oil availability before running near the 2,900 r/min oil ceiling.
- On slash-size and T-code bearings confirm the full code on both cone and cup before fitting: the 85 mm bore alone does not identify the cup, and a mismatched cone/cup set has no catalogue rating.
- ISO 355 makes the 85×180 mm envelope interchangeable but not the ratings: NTN prints 445/525 kN for this execution, and a cheaper same-number part can differ in roller complement and steel.
- Minimum load matters at high speed: an unloaded 32317U at a large fraction of 2,100 r/min lets rollers skid and smear the cone rib; spring-preload lightly loaded pair arrangements.
- The 445/525 kN ratings and 59 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 32317U (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 32317U?
32317U is a metric 4T tapered roller bearing to ISO 355: 85 mm bore, 180 mm outside diameter and 63.5 mm assembled width T (3.346 × 7.087 × 2.5 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 445 kN, C0 525 kN, Pu 59 kN, grease limiting speed 2,100 r/min, oil speed 2,900 r/min, mass about 7220 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 32317U?
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 (32317U); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 32317U designation encode the 85 mm bore and what is 2GD?
last two digits 17 are the ISO bore code, ×5 = 85 mm (codes 00–03 use the 10/12/15/17 exception table). The 180 mm OD and 63.5 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 32317U list two speeds, 2,100 and 2,900 r/min?
The lower figure, 2,100 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 32317U at 2,900 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 32317U mean?
Suffix reading on 32317U: 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.