21314 bearing: complete specifications & equivalents
The 21314 is a ISO 15 radial bearing sized 70 x 150 x 35 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Bore diameter d | 70 mm |
| Outer diameter D | 150 mm |
| Width B | 35 mm |
| Seal / shield | open |
| Internal clearance | CN / C3 / C4 available |
| Tolerance class | P0 |
| Cage | steel |
| Operating temperature | -30 to +120 °C |
| Mass (geometry estimate) | 2469 g |
| Standard | ISO 15 |
| Catalog version | iso15-srb-geometry |
| Last verified | 2026-09-24 |
Source: ISO 15 boundary-dimensions standard · extracted 2026-09-24
Standard-interchange bearing: dimensions per ISO 15; CN clearance, P0 tolerance and a stamped-steel cage are catalogue defaults unless the supplier states otherwise, and mass is a geometry-derived estimate. Brand catalogue load ratings and limiting speeds for 21314 are being backfilled — use the inquiry form for certified values.
Dimensions in inches & 21300-series range
| Bore d | 2.756 in |
|---|---|
| Outer diameter D | 5.906 in |
| Width B | 1.378 in |
| ISO bore code | 14 |
| Radial section height (D−d)/2 | 40 mm |
| Smallest bore in 21300-series | 50 mm |
| Largest outer diameter in 21300-series | 240 mm |
| Width range across 21300-series | 27–50 mm |
| Bore position in 21300-series (smallest first) | 5 of 12 |
| Bore above smallest 21300-series size | 20 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 21314 | 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 21314 model number is decoded
In the 21300-series (ISO 15 dimension series) the leading 2 marks a double-row spherical roller and the last two digits of 21314 encode the bore: code 14 = 70 mm (code × 5 from 04 upward). The ISO 15 envelope is 150 mm outside diameter and 35 mm width — 2.756 × 5.906 × 1.378 in, with a 40.0 mm radial section height. Two rows of symmetrical barrel rollers on a common sphered outer raceway self-align to shaft deflection while carrying heavy radial load and bidirectional axial load. Typical catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 internal clearance; K variants use a 1:12 tapered bore on an adapter sleeve — verify against the mounting arrangement.
Typical equipment & failure modes
Common applications
- conveyor head and tail pulleys
- vibrating screens, feeders and shakeout machines
- paper machine felt and press rolls
- industrial gearbox and drive shafts
- elevator winches and hoist drums
Known failure patterns
- lubricant starvation and cage wear where the relubrication interval ignores the slow-speed, dirty operating regime
- water and grit pitting of open bearings in mining and pulping duty after the housing seals degrade
- unloaded-row scuffing when pure thrust exceeds the catalogue axial capacity and one roller row unloads completely
- thermal seizure when an interference shaft fit plus hot running removes all residual radial clearance from a CN bearing
- raceway and roller spalling after the L10 life or from sustained overload and shock in crusher duty
Selection pitfalls — read before you substitute
- On this 70 mm-bore 21314, specify C3 clearance as the default for an interference inner-ring fit and verify residual play after mounting; a medium-section row that ran free on the bench can be fully clamped at operating temperature on the 70 mm shaft.
- The 213 series at 70 mm bore keeps the 35 mm width comparatively narrow for its 150 mm OD; it fits restricted axial space but carries less load than a 22314, so substitution into heavy 223 duty — even at identical bore and OD — will shorten life.
- Check the shoulder geometry for 21314: a generous fillet on the 70 mm shaft looks strong but stops the 35 mm inner ring seating home; use the catalogue corner-relief radius and provide a withdrawal groove so the 40.0 mm-section outer ring presses flush in the 150 mm housing.
- Large 21314 tapers should be mounted with a hydraulic nut or oil injection: controlled drive-up sets the residual radial clearance on the 35 mm-wide double row, whereas bar-and-spanner force either under-drives (fretting) or over-drives (thermal seizure on first hot run).
- Read the damage pattern on a removed 21314: spalling concentrated on one side of the 150 mm outer race points to misalignment or thrust overload, while uniform roller-end smearing means minimum-load skidding — the two failures demand opposite corrections.
- Self-aligning is not a licence to ignore alignment: 21314 accommodates typically around 1° of angular misalignment under normal load (roughly 2° only in favourable, light-load conditions) — the exact figure falls with load, so check the catalogue value rather than designing to the maximum.
- Spherical rollers need a minimum radial load to keep the rollers driven — as a rule of thumb about 2% of the basic dynamic load rating; an unloaded 21314 on an idler or in a cold-start drive will skid and smear, so add preload, reduce the bearing size or use a sealed grease-filled variant.
Frequently asked questions
What are the dimensions of a 21314 spherical roller bearing?
A 21314 double-row spherical roller bearing per ISO 15 has a 70 mm bore, 150 mm outer diameter and 35 mm width (2.756 × 5.906 × 1.378 in), a 40.0 mm radial section and roughly 2469 g geometry-based estimated mass; catalogue masses vary with cage and design.
How does the 21314 bore code work?
The leading 2 in 21314 denotes a double-row spherical roller, the middle digits give the ISO 15 dimension series, and the last two digits are bore code 14: 14 × 5 = 70 mm. The 150 mm OD and 35 mm width come from the dimension series (21300), not from the bore code alone.
How much misalignment can a 21314 accommodate?
Thanks to the sphered outer ring raceway, 21314 normally accommodates angular misalignment of around 1° under load (up to about 2° in favourable, lightly loaded conditions); the permissible value is smaller under full load and depends on clearance and cage design, so check the catalogue figure for the actual duty.
What is the difference between 21314 and 21314K?
The plain 21314 has a cylindrical bore for a straight shaft seat. The K suffix denotes a 1:12 tapered bore, normally mounted on an H3xx adapter sleeve over a commercial shaft (or directly on a tapered journal); the bearing is driven up the sleeve to a specified residual clearance and locked with a KM nut and tab washer.
Should the 21314 be ordered with CN, C3 or C4 clearance?
Use C3 as the usual default when the rotating inner ring has an interference fit, because the fit plus thermal expansion reduces residual play; choose C4 (often with a vibratory cage design) for screens and feeders; order CN mainly for loose fits on stationary shafts or split housings. A W33 outer-ring lubrication groove is a separate, commonly combined option.
Reviewed & verified by the MPN Base engineering desk against source catalog iso15-srb-geometry on 2026-09-24. Read our editorial & correction policy.