32316U bearing: complete specifications & equivalents
The 32316U is a ISO 355 radial bearing sized 80 x 170 x 61.5 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 80 mm |
| Outer diameter D | 170 mm |
| Width B | 61.5 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 440 kN |
| Basic static load rating C0 | 525 kN |
| Fatigue load limit Pu | 60 kN |
| Limiting speed (mechanical) | 2300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 6480 g |
| Manufacturer designation | NTN 32316U |
| 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 | 3.15 in |
|---|---|
| Outer diameter D | 6.693 in |
| Width B | 2.421 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 45 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) | 14 of 30 |
| Bore above smallest 32300-series size | 60 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 32316U | 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 32316U model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, the NTN order number 32316U denotes the extra-heavy 32300 family of metric tapered roller bearings, 80 mm bore, 170 mm outside diameter and 61.5 mm assembled width T (3.15 × 6.693 × 2.421 in) to the ISO 355 boundary plan. Reading the designation: the leading five digits follow the ISO 355 metric plan (dimension family plus two-digit bore code), and 32316U resolves to 80 mm bore; the NTN factory mark 4T is stamped on cone and cup but is a brand mark, not a size code, so the catalogue sku is printed without it. A tapered roller bearing reacts combined radial and one-direction axial load; NTN mounts 32316U cone and cup separately and adjusts end play or preload against a second bearing, so the arrangement locates the shaft in both directions. Speed planning uses both catalogue columns: grease 2,300 r/min is the cage/rib mechanical ceiling for 32316U, oil 3,000 r/min is available with circulating oil — a 700 r/min margin at this size. Mount the 80 mm-bore cone on the shaft first (induction heat, max 120 °C), fit the cup square in its housing, then set preload or end play; never drive the cup home through the rollers of 32316U.
Typical equipment & failure modes
Common applications
- rolling-mill auxiliary and pinion-stand shafts
- large conveyor and bucket-elevator pulleys
- mineral-processing feeder and crusher auxiliaries
- marine winch and deck-machinery shafts
Known failure patterns
- cup creep and housing fretting when the specified outer-ring press fit is not achieved
- preload loss from racewear when one bearing of the paired set is replaced without re-adjusting end play
- rib scoring when axial load is carried beyond the cone rib capacity of the adjusted pair
- cage fatigue when the pair is run continuously near the grease limiting speed without oil cooling
- fretting corrosion on a loose cone seat that creeps under rotating load
Selection pitfalls — read before you substitute
- Mount the 80 mm cone by induction heating (max 120 °C) and the cup with a press sleeve; the 6480 g ring mass makes cocking during fitting a direct raceway-brinelling risk.
- The extra-heavy 32300 family at 80 mm bore (170×61.5 mm assembled) carries more capacity than the lighter 320/329 sections but generates more preload heat; confirm oil availability before running near the 3,000 r/min oil ceiling.
- Open 32316U units have no seals: a wheel-hub or gearbox application needs external sealing or the 2,300 r/min grease figure is meaningless once water reaches the cone rib.
- Do not confuse T (61.5 mm assembled width of cone + cup) with the cone width when drawing spacers; an abutment sized to T instead of the ring width leaves the cup unseated.
- Do not confuse T (61.5 mm assembled width of cone + cup) with the cone width when drawing spacers; an abutment sized to T instead of the ring width leaves the cup unseated.
- The 440/525 kN ratings and 60 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 32316U (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 32316U?
32316U is a metric 4T tapered roller bearing to ISO 355: 80 mm bore, 170 mm outside diameter and 61.5 mm assembled width T (3.15 × 6.693 × 2.421 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 440 kN, C0 525 kN, Pu 60 kN, grease limiting speed 2,300 r/min, oil speed 3,000 r/min, mass about 6480 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 32316U?
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 (32316U); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 32316U designation encode the 80 mm bore and what is 2GD?
last two digits 16 are the ISO bore code, ×5 = 80 mm (codes 00–03 use the 10/12/15/17 exception table). The 170 mm OD and 61.5 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 32316U list two speeds, 2,300 and 3,000 r/min?
The lower figure, 2,300 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 32316U at 3,000 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 32316U mean?
Suffix reading on 32316U: 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.