32021XU bearing: complete specifications & equivalents
The 32021XU is a ISO 355 radial bearing sized 105 x 160 x 35 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 | 35 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 223 kN |
| Basic static load rating C0 | 335 kN |
| Fatigue load limit Pu | 37.5 kN |
| Limiting speed (mechanical) | 2100 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2440 g |
| Manufacturer designation | NTN 32021XU |
| Standard | ISO 355 |
| 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 & 32000-series range
| Bore d | 4.134 in |
|---|---|
| Outer diameter D | 6.299 in |
| Width B | 1.378 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 27.5 mm |
| Smallest bore in 32000-series | 20 mm |
| Largest outer diameter in 32000-series | 650 mm |
| Width range across 32000-series | 15–130 mm |
| Bore position in 32000-series (smallest first) | 21 of 43 |
| Bore above smallest 32000-series size | 85 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 32021XU | 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 32021XU model number is decoded
32021XU is a metric single-row tapered roller bearing in the NTN 4T programme: a pressed-steel cage guides profiled rollers between a separable cone and cup on the 105×160 mm ISO 355 envelope, with 35 mm overall assembled width T. On the NTN nameplate the parts carry 4T plus the bare code, while 2203E orders 32021XU by the metric ISO 355 number (ISO series abbreviation 4DC): 105 mm bore, 160 mm OD. The pressed-steel cage and surface-finished roller ends are standard 4T execution; ULTAGE-marked variants use upgraded material and internal geometry aimed at longer rating life with the same ISO 355 envelope. Selection: C 223 kN against C0 335 kN gives a C0/C ratio of 1.50 for the 105 mm bore, and the equivalent combined load must keep below the rating at the target L10 with the pair counted as one unit. With a rotating shaft a m6/n6 shaft seat and a press-fit cup are typical catalogue practice for 32021XU; reverse the logic if the cup rotates, and re-verify against load direction and magnitude.
Typical equipment & failure modes
Common applications
- large conveyor and bucket-elevator pulleys
- mineral-processing feeder and crusher auxiliaries
- marine winch and deck-machinery shafts
- paper-machine press-section rolls
Known failure patterns
- cup creep and housing fretting when the specified outer-ring press fit is not achieved
- smearing on the roller large ends and cone rib after a dry start with preload but no oil film
- flaking on one cone only when a back-to-back / face-to-face pair is loaded unevenly by a bent shaft
- pressed-steel cage pocket wear from roller skid at light radial load and high speed
- false brinelling on a stationary paired set exposed to external vibration
Selection pitfalls — read before you substitute
- Mount the 105 mm cone by induction heating (max 120 °C) and the cup with a press sleeve; the 2440 g ring mass makes cocking during fitting a direct raceway-brinelling risk.
- The thin 35 mm section of 32021XU is built for low friction and tight envelopes, not the heavy preload of a 322/323 set; over-tightening adjustment on this 105 mm bore smears the roller ends against the rib.
- Back-to-back and face-to-face arrangements react differently to shaft bending: pick the pair orientation for the moment load before locking the 105 mm shoulder geometry, because retrofitting flips the cups.
- On slash-size and T-code bearings confirm the full code on both cone and cup before fitting: the 105 mm bore alone does not identify the cup, and a mismatched cone/cup set has no catalogue rating.
- Replacing one half of an adjusted pair without resetting end play negates the 35 mm T dimension logic: re-adjust the set and re-verify the contact pattern rather than reusing the old spacer stack.
- The 223/335 kN ratings and 37.5 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 32021XU (ISO 355 4DC); internal geometry legitimately differs between manufacturers, so re-verify ratings, adjustment and suffix before substituting another make on a rated drive.
Frequently asked questions
What are the dimensions and catalogue ratings of NTN 32021XU?
32021XU is a metric 4T tapered roller bearing to ISO 355: 105 mm bore, 160 mm outside diameter and 35 mm assembled width T (4.134 × 6.299 × 1.378 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 223 kN, C0 335 kN, Pu 37.5 kN, grease limiting speed 2,100 r/min, oil speed 2,800 r/min, mass about 2440 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 32021XU?
4T is NTN's tapered roller bearing brand mark, stamped on the cone and cup in the factory. It identifies the NTN 4T programme and is not a dimension, so the catalogue and this page list the bare ISO 355 number (32021XU); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 32021XU designation encode the 105 mm bore and what is 4DC?
last two digits 21 are the ISO bore code, ×5 = 105 mm (codes 00–03 use the 10/12/15/17 exception table). The 160 mm OD and 35 mm assembled T follow the ISO 355 dimension-series plan. 4DC is the maker-neutral ISO 355 abbreviation for this dimension series (the same code other manufacturers print); 4T is NTN's own brand mark.
Why does 32021XU list two speeds, 2,100 and 2,800 r/min?
The lower figure, 2,100 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 32021XU at 2,800 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 32021XU mean?
Suffix reading on 32021XU: XU combines the X ISO boundary section with the U uprated internal design; U marks the reinforced/uprated internal design of the bare number, a separate order number with higher load capacity than the basic execution; the suffix is part of the order number and the variants are not interchangeable articles.
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.