16021 bearing: complete specifications & equivalents
The 16021 is a ISO 15 radial bearing sized 105 x 160 x 18 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 105 mm |
| Outer diameter D | 160 mm |
| Width B | 18 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 57.5 kN |
| Basic static load rating C0 | 50.5 kN |
| Fatigue load limit Pu | 3 kN |
| Limiting speed (mechanical) | 4000 rpm |
| Mass | 1200 g |
| Manufacturer designation | NTN 16021 |
| Standard | ISO 15 |
| Catalog version | NTN Ball and Roller Bearings CAT.No.2203-3/E (2024) |
| Last verified | 2026-09-25 |
Source: catalog reference (NTN Ball and Roller Bearings CAT.No.2203-3/E (2024)) · extracted 2026-09-25
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN Ball and Roller Bearings CAT.No.2203-3/E (2024)); 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 & 16000-series range
| Bore d | 4.134 in |
|---|---|
| Outer diameter D | 6.299 in |
| Width B | 0.709 in |
| ISO bore code | 21 |
| Radial section height (D−d)/2 | 27.5 mm |
| Smallest bore in 16000-series | 12 mm |
| Largest outer diameter in 16000-series | 540 mm |
| Width range across 16000-series | 7–57 mm |
| Bore position in 16000-series (smallest first) | 21 of 38 |
| Bore above smallest 16000-series size | 93 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 16021 | ISO-INTERCHANGE | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension interchange; ratings above are NTN 2203-3/E values and differ by brand — verify 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 16021 model number is decoded
In the 16000-series (the narrow extra-light section of ISO 15) the last two digits encode the bore: 16021 carries bore code 21 = 105 mm. Outside diameter 160 mm and width 18 mm come from the ISO 15 boundary-dimensions general plan. With no seal suffix the bearing is open: no shields or seals are fitted and lubrication is supplied by the application. For normal-load mounting with a rotating inner ring on a 105 mm shaft, typical catalogue practice is a m6 shaft seat with an H7 housing bore — verify against the actual load direction and magnitude. In the NTN catalogue this open execution carries the bare designation; protected variants are ordered separately with suffixes ZZ (shields), LLB/LLF (non-contact seals), LLH (low-torque contact seal) and LLU (contact seal).
Typical equipment & failure modes
Common applications
- hoists and winches
- heavy conveyors
- pulp and paper machinery
- medium and heavy industrial drives
Known failure patterns
- contamination wear from dust and dirt ingress through the open arrangement
- lubricant starvation when no regreasing interval is maintained
- fretting corrosion on a loose shaft seat
- cage damage from operation beyond the limiting speed
Selection pitfalls — read before you substitute
- Mount this 105 mm bore bearing by heating the inner ring (induction heater, max 120 °C) — never drive it home through the outer ring or balls, that brinells the raceways.
- The 160xx narrow section at 105 mm bore shares the 160 mm outside diameter of the 6021 but is only 18 mm wide; a 6021 in a 18 mm-wide seat is loose axially and the reverse swap will not fit — match width as well as bore and outside diameter.
- The open 16021 has no lubricant retention: grease escapes and contaminants migrate straight into the 105×160×18 mm raceway, so specify a sealed arrangement for dusty or washdown duty.
- Open bearings tolerate the highest speeds in the 16000-series but need a defined regreasing interval; run-to-failure lubrication is the dominant cause of early failure in open 16021 units.
- Do not quieten a noisy bearing by preloading it: the 16000-series is a deep-groove design, not angular-contact; axial preload raises temperature and shortens grease life.
- The open 16021 has no integral sealing; in the NTN 2203 catalogue the protected variants carry suffixes ZZ (non-contact steel shields), LLB/LLF (non-contact rubber seals), LLU (contact rubber seals) and LLH (a low-torque contact seal with higher speed capability than LLU). A JR or JRX suffix (as printed for some thin-section sizes) denotes a pressed-steel cage, not a seal.
- The 57.5/50.5 kN load ratings, 3 kN fatigue load limit Cu and 1200 g mass here are NTN Ball and Roller Bearings CAT.No.2203-3/E figures for 16021; this seal/size combination has no counterpart from another catalogue on this site, so the page rests on a single manufacturer source — internal geometry and ratings legitimately differ between brands, so re-verify before substituting in a rated drive.
Frequently asked questions
What are the dimensions of a 16021 bearing?
A 16021 deep-groove ball bearing has a 105 mm bore, 160 mm outer diameter and 18 mm width (4.134 × 6.299 × 0.709 in), per ISO 15 boundary dimensions. It is an open bearing with no seals or shields.
How does the 16021 bore code work?
The last two digits of 16021 are bore code 21, giving 21 × 5 = 105 mm bore. The 160 mm outside diameter and 18 mm width follow the ISO 15 diameter series, not the bore code alone.
What does no suffix on 16021 mean?
A bare 16021 designation means open: no shields or seals, normal CN radial clearance and P0 normal tolerance unless further suffixes are ordered. The application must supply and retain the lubrication.
How does the 16000 compare with other series at the same 105 mm bore?
160 is the narrow extra-light section: 160×18 mm with a 27.5 mm radial section at 105 mm bore. It has the same bore and outside diameter as the 6021 but a narrower ring, so the two are not width-interchangeable; it appears in the manufacturer catalogues used on this site.
What is the NTN designation and catalogue data for 16021?
In the NTN Ball and Roller Bearings catalogue (CAT.No.2203-3/E, 2024) this size is listed as 16021 — the open (unsealed) execution, 105×160×18 mm per ISO 15. Quoted values: C 57.5 kN, C0 50.5 kN, Cu 3 kN, mass 1200 g. Grease limiting speed 4000 rpm. The industry-neutral page spelling 16021 follows the seal-suffix convention used across this site, not NTN order-number spelling.
Reviewed & verified by the MPN Base engineering desk against source catalog NTN Ball and Roller Bearings CAT.No.2203-3/E (2024) on 2026-09-25. Read our editorial & correction policy.