32918XU bearing: complete specifications & equivalents
The 32918XU is a ISO 355 radial bearing sized 90 x 125 x 23 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 90 mm |
| Outer diameter D | 125 mm |
| Width B | 23 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 108 kN |
| Basic static load rating C0 | 168 kN |
| Fatigue load limit Pu | 20 kN |
| Limiting speed (mechanical) | 2700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 815 g |
| Manufacturer designation | NTN 32918XU |
| 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 | 3.543 in |
|---|---|
| Outer diameter D | 4.921 in |
| Width B | 0.906 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 17.5 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) | 12 of 37 |
| Bore above smallest 32900-series size | 55 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 32918XU | 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 32918XU model number is decoded
For a 90 mm shaft with a thrust component, NTN lists 32918XU, a metric 4T tapered roller bearing of 108 kN C and 168 kN C0 inside the 125 mm OD, 23 mm-wide assembled set. The last two digits 18 are the ISO bore code, ×5 = 90 mm (codes 00–03 use the 10/12/15/17 exception table) under the ISO 355 numbering; the 23 mm value printed here is T, the width of the fully assembled cone-plus-cup set, not the inner-ring width alone. Individually mounted, 32918XU takes axial force in one direction only; two bearings are arranged face-to-face (X) or back-to-back (O) according to the moment stiffness and misalignment the shaft requires. The fatigue load limit Pu printed for 32918XU is 20 kN; in the adjusted-life equation that is the equivalent-load floor below which high reliability is expected even under contamination. Mount the 90 mm-bore cone on the shaft first (induction heat, max 120 °C), fit the cup square in its housing, then set preload or end play; never drive the cup home through the rollers of 32918XU.
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
- flaking on one cone only when a back-to-back / face-to-face pair is loaded unevenly by a bent shaft
- smearing on the roller large ends and cone rib after a dry start with preload but no oil film
- cage fatigue when the pair is run continuously near the grease limiting speed without oil cooling
- indentation of the raceways by hard particles in unsealed open arrangements
Selection pitfalls — read before you substitute
- Mount the 90 mm cone by induction heating (max 120 °C) and the cup with a press sleeve; the 815 g ring mass makes cocking during fitting a direct raceway-brinelling risk.
- The thin 23 mm section of 32918XU is built for low friction and tight envelopes, not the heavy preload of a 322/323 set; over-tightening adjustment on this 90 mm bore smears the roller ends against the rib.
- Do not confuse T (23 mm assembled width of cone + cup) with the cone width when drawing spacers; an abutment sized to T instead of the ring width leaves the cup unseated.
- Minimum load matters at high speed: an unloaded 32918XU at a large fraction of 2,700 r/min lets rollers skid and smear the cone rib; spring-preload lightly loaded pair arrangements.
- Never fit the 90 mm cone by hammering the 125 mm cup: force for both press fits goes through the ring faces only, or brinell marks release as noise within the first running hours.
- The 108/168 kN ratings and 20 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 32918XU (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 32918XU?
32918XU is a metric 4T tapered roller bearing to ISO 355: 90 mm bore, 125 mm outside diameter and 23 mm assembled width T (3.543 × 4.921 × 0.906 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 108 kN, C0 168 kN, Pu 20 kN, grease limiting speed 2,700 r/min, oil speed 3,600 r/min, mass about 815 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 32918XU?
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 (32918XU); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 32918XU designation encode the 90 mm bore and what is 2BC?
last two digits 18 are the ISO bore code, ×5 = 90 mm (codes 00–03 use the 10/12/15/17 exception table). The 125 mm OD and 23 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 32918XU list two speeds, 2,700 and 3,600 r/min?
The lower figure, 2,700 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 32918XU at 3,600 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 32918XU mean?
Suffix reading on 32918XU: 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.