32310C bearing: complete specifications & equivalents
The 32310C is a ISO 355 radial bearing sized 50 x 110 x 42.25 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 50 mm |
| Outer diameter D | 110 mm |
| Width B | 42.25 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 178 kN |
| Basic static load rating C0 | 220 kN |
| Limiting speed (mechanical) | 3500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1970 g |
| Manufacturer designation | NTN 32310C |
| 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 | 1.969 in |
|---|---|
| Outer diameter D | 4.331 in |
| Width B | 1.663 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 30 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) | 8 of 30 |
| Bore above smallest 32300-series size | 30 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 32310C | 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 32310C model number is decoded
32310C is a metric single-row tapered roller bearing in the NTN 4T programme: a pressed-steel cage guides profiled rollers between a separable cone and cup on the 50×110 mm ISO 355 envelope, with 42.25 mm overall assembled width T. Reading the designation: the leading five digits follow the ISO 355 metric plan (dimension family plus two-digit bore code), and 32310C resolves to 50 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. Suffix reading on 32310C: the trailing A/C/D (or E1) letter marks an NTN contact-angle or internal-design revision of the base number, not a seal or clearance code; the suffix is part of the order number and the variants are not interchangeable articles. The 30.0 mm section height over the 50 mm bore positions the load centre; axial location of the pair depends on that contact line, so spacer faces must be square within the P0 tolerance of the bearing. After mounting check the contact pattern with marking blue: a pattern biased to the large or small roller end means the 50 mm pair is misadjusted and the 42.25 mm T set will edge-load in service.
Typical equipment & failure modes
Common applications
- industrial gearbox and speed-reducer shafts
- bevel and helical pinion drives with high thrust component
- pump and compressor drive shafts carrying combined load
- machine-tool gearbox and headstock 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
- edge loading when shaft deflection exceeds the few arc-minutes of misalignment the adjusted pair allows
Selection pitfalls — read before you substitute
- Hub and pinion bearings of this 50 mm bore class are commonly adjusted in pairs; verify end play against the axle drawing and re-torque after bedding-in rather than trusting the initial preload on 32310C.
- The extra-heavy 32300 family at 50 mm bore (110×42.25 mm assembled) carries more capacity than the lighter 320/329 sections but generates more preload heat; confirm oil availability before running near the 4,600 r/min oil ceiling.
- The 30.0 mm section leaves little room for an oversized shaft fillet; check the mounting-chamfer table for 32310C or the ring will bottom out on the radius instead of the shoulder face.
- ISO 355 makes the 50×110 mm envelope interchangeable but not the ratings: NTN prints 178/220 kN for this execution, and a cheaper same-number part can differ in roller complement and steel.
- ISO 355 makes the 50×110 mm envelope interchangeable but not the ratings: NTN prints 178/220 kN for this execution, and a cheaper same-number part can differ in roller complement and steel.
- The 178/220 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 32310C (ISO 355 5FD); 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 32310C?
32310C is a metric 4T tapered roller bearing to ISO 355: 50 mm bore, 110 mm outside diameter and 42.25 mm assembled width T (1.969 × 4.331 × 1.663 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 178 kN, C0 220 kN (2203E prints no Pu for this size), grease limiting speed 3,500 r/min, oil speed 4,600 r/min, mass about 1970 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 32310C?
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 (32310C); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 32310C designation encode the 50 mm bore and what is 5FD?
last two digits 10 are the ISO bore code, ×5 = 50 mm (codes 00–03 use the 10/12/15/17 exception table). The 110 mm OD and 42.25 mm assembled T follow the ISO 355 dimension-series plan. 5FD 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 32310C list two speeds, 3,500 and 4,600 r/min?
The lower figure, 3,500 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 32310C at 4,600 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 32310C mean?
Suffix reading on 32310C: the trailing A/C/D (or E1) letter marks an NTN contact-angle or internal-design revision of the base number, not a seal or clearance code; 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.