32911XU bearing: complete specifications & equivalents
The 32911XU is a ISO 355 radial bearing sized 55 x 80 x 17 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 55 mm |
| Outer diameter D | 80 mm |
| Width B | 17 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 49.5 kN |
| Basic static load rating C0 | 73.5 kN |
| Fatigue load limit Pu | 8.95 kN |
| Limiting speed (mechanical) | 4300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 274 g |
| Manufacturer designation | NTN 32911XU |
| 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 & 32900-series range
| Bore d | 2.165 in |
|---|---|
| Outer diameter D | 3.15 in |
| Width B | 0.669 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 12.5 mm |
| Smallest bore in 32900-series | 35 mm |
| Largest outer diameter in 32900-series | 600 mm |
| Width range across 32900-series | 14–100 mm |
| Bore position in 32900-series (smallest first) | 5 of 37 |
| Bore above smallest 32900-series size | 20 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 32911XU | 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 32911XU model number is decoded
32911XU is the NTN 4T catalogue entry for a 55×80×17 mm metric tapered roller bearing — separable cone and cup, designed for combined radial and axial load as an individually adjusted bearing. NTN also quotes this bearing with its ISO 355 dimension-series abbreviation, 2BC, which is the maker-neutral cross-reference for the 55×80 mm envelope; 4T is NTN's own tapered-roller brand mark on the parts. The printed contact-angle geometry gives the extra-light thin-section 32900 family its characteristic load split — at 49.5/73.5 kN (C/C0) the static rating is about 1.48× C, typical of tapered bearings proportioned for heavy combined duty. The two speed columns differ by a factor of .75 (grease/limiting 4,300 vs oil 5,700 r/min); heat generation at the cone rib decides which lubrication a real 32911XU arrangement can sustain. Re-adjustment after bedding-in is standard practice: re-check end play once the paired 32911XU arrangement has run in, because initial seat seating relaxes the set preload slightly.
Typical equipment & failure modes
Common applications
- truck and bus wheel hubs in paired arrangements
- industrial gearbox and speed-reducer shafts
- bevel and helical pinion drives with high thrust component
- pump and compressor drive shafts carrying combined load
Known failure patterns
- cone-raceway spalling at the large rib when preload is set too high for the lubricant film
- 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
- edge loading when shaft deflection exceeds the few arc-minutes of misalignment the adjusted pair allows
Selection pitfalls — read before you substitute
- Hub and pinion bearings of this 55 mm bore class are commonly adjusted in pairs; verify end play against the axle drawing and re-torque after bedding-in rather than trusting the initial preload on 32911XU.
- The thin 17 mm section of 32911XU is built for low friction and tight envelopes, not the heavy preload of a 322/323 set; over-tightening adjustment on this 55 mm bore smears the roller ends against the rib.
- On slash-size and T-code bearings confirm the full code on both cone and cup before fitting: the 55 mm bore alone does not identify the cup, and a mismatched cone/cup set has no catalogue rating.
- Grease packs must leave free volume in the 17 mm-wide set; over-greasing a paired bearing churning at the 5,700 r/min oil-band speed raises temperature and destroys the preload setting.
- Minimum load matters at high speed: an unloaded 32911XU at a large fraction of 4,300 r/min lets rollers skid and smear the cone rib; spring-preload lightly loaded pair arrangements.
- The 49.5/73.5 kN ratings and 8.95 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 32911XU (ISO 355 2BC); 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 32911XU?
32911XU is a metric 4T tapered roller bearing to ISO 355: 55 mm bore, 80 mm outside diameter and 17 mm assembled width T (2.165 × 3.15 × 0.669 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 49.5 kN, C0 73.5 kN, Pu 8.95 kN, grease limiting speed 4,300 r/min, oil speed 5,700 r/min, mass about 274 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 32911XU?
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 (32911XU); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 32911XU designation encode the 55 mm bore and what is 2BC?
last two digits 11 are the ISO bore code, ×5 = 55 mm (codes 00–03 use the 10/12/15/17 exception table). The 80 mm OD and 17 mm assembled T follow the ISO 355 dimension-series plan. 2BC 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 32911XU list two speeds, 4,300 and 5,700 r/min?
The lower figure, 4,300 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 32911XU at 5,700 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 32911XU mean?
Suffix reading on 32911XU: 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.