21313K bearing: complete specifications & equivalents
The 21313K is a ISO 15 radial bearing sized 65 x 140 x 33 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 65 mm |
| Outer diameter D | 140 mm |
| Width B | 33 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 216 kN |
| Basic static load rating C0 | 228 kN |
| Fatigue load limit Pu | 31 kN |
| Limiting speed (mechanical) | 3100 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2510 g |
| Manufacturer designation | NTN 21313K |
| 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 | 2.559 in |
|---|---|
| Outer diameter D | 5.512 in |
| Width B | 1.299 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 37.5 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) | 6 of 14 |
| Bore above smallest 21300-series size | 25 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 21313-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 21313-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 21313K model number is decoded
NTN lists 21313K with a 1:12 tapered bore (K) and plain outer ring (no D1/W33 groove): 65 mm bore, 140 mm OD, 33 mm width, rated 3,100 r/min on grease. Numbering ties 21313K to its envelope and execution: same-number EA versus EM or plain variants share the 65 mm bore but differ in cage and sometimes mass, so they are quoted as separate articles. Suffix reading on 21313K: C is the cage/design code for the NTN 213 series, CK adding the tapered bore; K marks the 1:12 tapered bore; quote the full code because each suffix is a distinct article. Pu 31 kN against C0 228 kN anchors the contamination derating; for dirty mining duty the adjusted life of 21313K moves with cleanliness far more than with small C variations. Supply grease through the outer-ring feature during commissioning and at the calculated interval, rotating the 65 mm bore assembly by hand to distribute it across both rows.
Typical equipment & failure modes
Common applications
- heavy conveyor and bucket-excavator pulleys
- jaw/cone crusher eccentric and shaft positions
- paper-machine dryer and press rolls
- cement-mill and kiln auxiliary drives
Known failure patterns
- lubricant starvation at the centre rib area when the D1/W33 groove is not connected to a relubrication supply
- 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
- false brinelling on stopped machines exposed to screen or crusher vibration
- fretting corrosion between adapter sleeve and tapered bore when the drive-up is insufficient
Selection pitfalls — read before you substitute
- Mount the 65 mm ring with induction heat or the sleeve drive-up procedure; at 2510 g cocking damages the spherical raceways, and repositioning after seating is impractical.
- Minimum load must be maintained even at rest under vibration: an unloaded 21313K on a stopped screen false-brinells; parking brakes and shaker isolation both matter.
- K and K30 are different tapers — K is 1:12 and K30 is 1:30 on the wide series; an adapter sleeve for one will not mount the other 65 mm bearing, and drive-up procedures differ.
- Minimum load must be maintained even at rest under vibration: an unloaded 21313K on a stopped screen false-brinells; parking brakes and shaker isolation both matter.
- The two roller rows must share load equally — a tilted spacer or unequal abutment on the 33 mm-wide ring loads one row only and shows as asymmetric race polish during inspection.
- The 216/228 kN ratings, 31 kN Pu and 2510 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 21313K (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 21313K?
21313K is an NTN double-row spherical roller bearing to ISO 15: 65 mm bore, 140 mm OD and 33 mm width (2.559 × 5.512 × 1.299 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 216 kN, C0 228 kN, Pu 31 kN, grease limiting speed 3,100 r/min, oil 4,000 r/min, mass about 2510 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. 21313K 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 21313.
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. 21313K is the C design-code execution.
What do D1 and W33 mean on 21313K?
21313K 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 21313K 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 — 216 kN C / 228 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.