21310C bearing: complete specifications & equivalents
The 21310C is a ISO 15 radial bearing sized 50 x 110 x 27 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 | 27 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 131 kN |
| Basic static load rating C0 | 127 kN |
| Fatigue load limit Pu | 13.7 kN |
| Limiting speed (mechanical) | 4000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1210 g |
| Manufacturer designation | NTN 21310C |
| 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 & 21300-series range
| Bore d | 1.969 in |
|---|---|
| Outer diameter D | 4.331 in |
| Width B | 1.063 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 30 mm |
| Smallest bore in 21300-series | 40 mm |
| Largest outer diameter in 21300-series | 240 mm |
| Width range across 21300-series | 23–50 mm |
| Bore position in 21300-series (smallest first) | 3 of 14 |
| Bore above smallest 21300-series size | 10 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 21310CK | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same NTN 21300-series envelope, cage and ratings; this is the cylindrical-bore execution of the tapered-bore 21310CK (K/K30 sleeve or tapered-seat mounting). Verify shaft arrangement. |
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 21310C model number is decoded
21310C belongs to the 21300 series of NTN spherical rollers: self-aligning, high radial capacity, moderate axial load in either direction. Reading the full code: the number gives the 50×110 mm envelope, C/CK names the cage/capacity execution, no bore suffix means cylindrical bore for a direct shaft seat, and plain outer ring (no D1/W33 groove) completes the order number. The sphered outer raceway lets the inner-ring assembly pivot, accommodating shaft deflection and housing misalignment (around 1–2° for this class; use the 2203E value for the exact series) without edge loading the rollers. Grease/oil ratio: the 4,000 r/min limiting value is .77 of the 5,200 r/min oil value; heavy 27 mm-wide cages run hot in churning grease, so quantity and groove supply both matter. After mounting on a tapered seat, lock the nut and re-check clearance after a short running-in period, because sleeve seating and ring lift-off can change the residual clearance of the 50 mm set.
Typical equipment & failure modes
Common applications
- stone crusher and screen eccentric shafts
- papermaking and printing press rolls
- pump and fan shafts under heavy belt load
- marine propulsion auxiliary shafts
Known failure patterns
- raceway spalling at the roller ends when misalignment or deflection concentrates the line contact
- pressed EA cage fatigue under sustained vibration when minimum load is not maintained
- micro-pitting when the EHL film is thinner than the raceway composite roughness
- asymmetric wear on the two roller rows from sustained angular misalignment beyond the self-aligning range
- asymmetric wear on the two roller rows from sustained angular misalignment beyond the self-aligning range
Selection pitfalls — read before you substitute
- Vibrating-duty 50 mm bearings need the right clearance class and secure fits; verify the k5/m5 seat and relubrication routing rather than assuming the open 21310C is greased for life.
- Do not confuse EA and EM at the same number: 21310C carries C design-code; swapping to the other cage execution changes mass, speed behaviour and sometimes suitability for vibration, even though the 50×110 mm envelope is identical.
- 213-series C/CK executions use the C cage/design code — CK adds the 1:12 tapered bore; quote 21310C in full because a C cannot be mounted on an adapter-sleeve tapered seat.
- The D1/W33 groove only helps if the housing has a matching grease passage; mounting a grooved 21310C in a solid block with no port wastes the feature and leaves the centre rows under-lubricated.
- Minimum load must be maintained even at rest under vibration: an unloaded 21310C on a stopped screen false-brinells; parking brakes and shaker isolation both matter.
- The 131/127 kN ratings, 13.7 kN Pu and 1210 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 21310C (C design-code); another maker's same-envelope part revises internal geometry, so re-verify ratings and cage before substitution on vibrating or rated drives.
Frequently asked questions
What are the dimensions and catalogue data of 21310C?
21310C is an NTN double-row spherical roller bearing to ISO 15: 50 mm bore, 110 mm OD and 27 mm width (1.969 × 4.331 × 1.063 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 131 kN, C0 127 kN, Pu 13.7 kN, grease limiting speed 4,000 r/min, oil 5,200 r/min, mass about 1210 g. It is open, with pressed-steel cage of the 213-series C design.
What is the difference between the K/K30 tapered bore and the cylindrical bore versions?
21310C has a cylindrical bore and mounts directly on a machined shaft seat. Its tapered-bore counterpart is 21310CK (K = 1:12, or K30 = 1:30 on the wide series), intended for adapter/withdrawal-sleeve mounting.
What do EA and EM mean on NTN spherical roller bearings?
EA is the NTN standard-capacity/high-capacity execution with a pressed sheet-steel window cage; EM is the high-capacity execution with a one-piece machined brass cage. Both use the optimised symmetric-roller design, but cage identity changes mass, speed behaviour and suitability for duties like vibrating screens, so they are separate order numbers. 21310C is the C design-code execution.
What do D1 and W33 mean on 21310C?
21310C is listed without a D1/W33 outer-ring groove in 2203E; lubrication is supplied from the ring sides. D1 (NTN spelling) and W33 add the annular groove plus holes and are ordered as distinct suffixed executions of the same envelope.
How much misalignment and axial load can 21310C take?
The sphered outer raceway compensates static and dynamic misalignment in the order of 1–2° (verify the exact 2203E figure for the 21300 series); beyond that, load concentrates on one roller row. Load is predominantly radial with a moderate axial share in either direction — 131 kN C / 127 kN C0 — but sustained pure axial load is not recommended because it unloads one row.
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.