21317-NTN bearing: complete specifications & equivalents
The 21317-NTN is a ISO 15 radial bearing sized 85 x 180 x 41 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 85 mm |
| Outer diameter D | 180 mm |
| Width B | 41 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 320 kN |
| Basic static load rating C0 | 355 kN |
| Fatigue load limit Pu | 45 kN |
| Limiting speed (mechanical) | 2400 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 5350 g |
| Manufacturer designation | NTN 21317 |
| 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 | 3.346 in |
|---|---|
| Outer diameter D | 7.087 in |
| Width B | 1.614 in |
| ISO bore code | 17 |
| Radial section height (D−d)/2 | 47.5 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) | 10 of 14 |
| Bore above smallest 21300-series size | 45 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 21317K | 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 21317K (K/K30 sleeve or tapered-seat mounting). Verify shaft arrangement. |
| 21317 | SKF | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
| 21317-EK | SKF | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
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 21317-NTN model number is decoded
For heavy radial load with misalignment on a 85 mm shaft, NTN supplies 21317: sphered outer raceway, two roller rows, pressed-steel cage of the 213-series C design, oil speed 3,100 r/min. The leading digits are the ISO 15 dimension series (21300 series); the bore code resolves to 85 mm (two-digit code ×5, with the 00–03 exception table), and 180 mm OD / 41 mm width follow the general plan. The plain outer ring (no D1/W33 groove) makes relubrication part of the design: fresh grease reaches the rolling elements through the outer-ring feature rather than relying solely on end-side packing. Pu 45 kN against C0 355 kN anchors the contamination derating; for dirty mining duty the adjusted life of 21317 moves with cleanliness far more than with small C variations. Fit the cylindrical-bore 21317 with the inner ring heated (max 120 °C) for the shaft interference; the outer ring slides into the housing with its spherical seat able to pivot after seating.
Typical equipment & failure modes
Common applications
- paper-machine dryer and press rolls
- cement-mill and kiln auxiliary drives
- large gearbox and marine gear shafts
- wind-turbine gearbox and rotor bearings
Known failure patterns
- lubricant starvation at the centre rib area when the D1/W33 groove is not connected to a relubrication supply
- 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
- hard-particle indentation through the open arrangement in dusty mining duty
- brinelling from static overload or a hammer blow during sleeve mounting
Selection pitfalls — read before you substitute
- Mount the 85 mm ring with induction heat or the sleeve drive-up procedure; at 5350 g cocking damages the spherical raceways, and repositioning after seating is impractical.
- Adapter-sleeve mounting requires the correct sleeve series and locknut for the 85 mm shaft; a sleeve sized to bore alone ignores thread, width and the oil-injection option on large K seats.
- 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 85 mm bearing, and drive-up procedures differ.
- Adapter-sleeve mounting requires the correct sleeve series and locknut for the 85 mm shaft; a sleeve sized to bore alone ignores thread, width and the oil-injection option on large K seats.
- 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 85 mm bearing, and drive-up procedures differ.
- The 320/355 kN ratings, 45 kN Pu and 5350 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 21317 (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 21317?
21317 is an NTN double-row spherical roller bearing to ISO 15: 85 mm bore, 180 mm OD and 41 mm width (3.346 × 7.087 × 1.614 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 320 kN, C0 355 kN, Pu 45 kN, grease limiting speed 2,400 r/min, oil 3,100 r/min, mass about 5350 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?
21317 has a cylindrical bore and mounts directly on a machined shaft seat. Its tapered-bore counterpart is 21317K (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. 21317 is the C design-code execution.
What do D1 and W33 mean on 21317?
21317 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 21317 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 — 320 kN C / 355 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.