21316K bearing: complete specifications & equivalents
The 21316K is a ISO 15 radial bearing sized 80 x 170 x 39 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 | 39 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 289 kN |
| Basic static load rating C0 | 315 kN |
| Fatigue load limit Pu | 30.5 kN |
| Limiting speed (mechanical) | 2500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 4470 g |
| Manufacturer designation | NTN 21316K |
| 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 | 3.15 in |
|---|---|
| Outer diameter D | 6.693 in |
| Width B | 1.535 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 45 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) | 9 of 14 |
| Bore above smallest 21300-series size | 40 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 21316-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same NTN 21300-series envelope, cage and ratings; this is the tapered-bore execution (K, 1:12) of the cylindrical-bore 21316-NTN — mounting (adapter/withdrawal sleeve or tapered seat, drive-up) differs. 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 21316K model number is decoded
For heavy radial load with misalignment on a 80 mm shaft, NTN supplies 21316K: sphered outer raceway, two roller rows, pressed-steel cage of the 213-series C design, oil speed 3,300 r/min. Reading the full code: the number gives the 80×170 mm envelope, C/CK names the cage/capacity execution, K marks the 1:12 tapered bore for adapter/withdrawal-sleeve mounting, and plain outer ring (no D1/W33 groove) completes the order number. The bearing accepts predominantly radial load with a moderate axial share, but is not a pure thrust bearing: sustained axial-only load skids the unloaded row and damages the C design-code cage. 80 mm bore is 3.15 in and 170 mm OD is 6.693 in; the ISO 15 envelope swaps between brands, but the 289/315 kN ratings and cage design are NTN 2203E values. Check the self-aligning movement after fitting: the housing should pivot freely around the sphered outer raceway; a pinched outer ring removes the alignment capacity the bearing was selected for.
Typical equipment & failure modes
Common applications
- cement-mill and kiln auxiliary drives
- large gearbox and marine gear shafts
- wind-turbine gearbox and rotor bearings
- large vibrating screens and mining feeders
Known failure patterns
- raceway spalling at the roller ends when misalignment or deflection concentrates the line contact
- cage damage when a mounting force is applied through the roller set instead of the ring face
- roller-end smearing during skidding starts under light load and high viscosity grease
- fretting corrosion between adapter sleeve and tapered bore when the drive-up is insufficient
- brinelling from static overload or a hammer blow during sleeve mounting
Selection pitfalls — read before you substitute
- Mount the 80 mm ring with induction heat or the sleeve drive-up procedure; at 4470 g cocking damages the spherical raceways, and repositioning after seating is impractical.
- Oil relubrication toward 3,300 r/min needs drain and level design; flooding the 39 mm cavity churns heat through the heavy roller set and cage despite the higher oil speed figure.
- The two roller rows must share load equally — a tilted spacer or unequal abutment on the 39 mm-wide ring loads one row only and shows as asymmetric race polish during inspection.
- Never substitute 21316K by envelope alone: the 315 kN C0 and 30.5 kN Pu are specific to the NTN C design-code execution, and vibrating duty depends heavily on cage identity.
- Never substitute 21316K by envelope alone: the 315 kN C0 and 30.5 kN Pu are specific to the NTN C design-code execution, and vibrating duty depends heavily on cage identity.
- The 289/315 kN ratings, 30.5 kN Pu and 4470 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 21316K (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 21316K?
21316K is an NTN double-row spherical roller bearing to ISO 15: 80 mm bore, 170 mm OD and 39 mm width (3.15 × 6.693 × 1.535 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 289 kN, C0 315 kN, Pu 30.5 kN, grease limiting speed 2,500 r/min, oil 3,300 r/min, mass about 4470 g. It is open, with pressed-steel cage of the 213-series C design and a 1:12 tapered bore.
What is the difference between the K/K30 tapered bore and the cylindrical bore versions?
K denotes a 1:12 tapered bore. 21316K mounts on an adapter sleeve (or tapered shaft seat) and is driven up to the specified residual clearance; its cylindrical-bore counterpart in the same envelope and ratings is 21316.
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. 21316K is the C design-code execution.
What do D1 and W33 mean on 21316K?
21316K 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 21316K 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 — 289 kN C / 315 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.