32910XU bearing: complete specifications & equivalents
The 32910XU is a ISO 355 radial bearing sized 50 x 72 x 15 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 50 mm |
| Outer diameter D | 72 mm |
| Width B | 15 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 39.5 kN |
| Basic static load rating C0 | 57 kN |
| Fatigue load limit Pu | 6.95 kN |
| Limiting speed (mechanical) | 4700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 192 g |
| Manufacturer designation | NTN 32910XU |
| 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 | 1.969 in |
|---|---|
| Outer diameter D | 2.835 in |
| Width B | 0.591 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 11 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) | 4 of 37 |
| Bore above smallest 32900-series size | 15 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 32910XU | 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 32910XU model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, the NTN order number 32910XU denotes the extra-light thin-section 32900 family of metric tapered roller bearings, 50 mm bore, 72 mm outside diameter and 15 mm assembled width T (1.969 × 2.835 × 0.591 in) to the ISO 355 boundary plan. Digit by digit, the bare number identifies the extra-light thin-section 32900 family and a bore code resolving to 50 mm; 72 mm OD and 15 mm assembled T are the matching ISO 355 boundary dimensions shared with other makers of the same dimension series. 2203E lists two speed ceilings for 32910XU: 4,700 r/min with grease lubrication (the limiting speed) and 6,300 r/min with oil, the higher oil value reflecting better heat removal from the cone rib. The 11.0 mm section height over the 50 mm bore positions the load centre; axial location of the pair depends on that contact line, so spacer faces must be square within the P0 tolerance of the bearing. Re-adjustment after bedding-in is standard practice: re-check end play once the paired 32910XU arrangement has run in, because initial seat seating relaxes the set preload slightly.
Typical equipment & failure modes
Common applications
- industrial gearbox and speed-reducer shafts
- bevel and helical pinion drives with high thrust component
- pump and compressor drive shafts carrying combined load
- machine-tool gearbox and headstock shafts
Known failure patterns
- cup creep and housing fretting when the specified outer-ring press fit is not achieved
- rib scoring when axial load is carried beyond the cone rib capacity of the adjusted pair
- preload loss from racewear when one bearing of the paired set is replaced without re-adjusting end play
- cage damage from a mounting blow delivered through the roller complement instead of the ring face
- water-induced pitting when the open bearing is exposed to washdown without external seals
Selection pitfalls — read before you substitute
- Hub and pinion bearings of this 50 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 32910XU.
- The thin 15 mm section of 32910XU is built for low friction and tight envelopes, not the heavy preload of a 322/323 set; over-tightening adjustment on this 50 mm bore smears the roller ends against the rib.
- Never fit the 50 mm cone by hammering the 72 mm cup: force for both press fits goes through the ring faces only, or brinell marks release as noise within the first running hours.
- Minimum load matters at high speed: an unloaded 32910XU at a large fraction of 4,700 r/min lets rollers skid and smear the cone rib; spring-preload lightly loaded pair arrangements.
- Grease packs must leave free volume in the 15 mm-wide set; over-greasing a paired bearing churning at the 6,300 r/min oil-band speed raises temperature and destroys the preload setting.
- The 39.5/57 kN ratings and 6.95 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 32910XU (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 32910XU?
32910XU is a metric 4T tapered roller bearing to ISO 355: 50 mm bore, 72 mm outside diameter and 15 mm assembled width T (1.969 × 2.835 × 0.591 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 39.5 kN, C0 57 kN, Pu 6.95 kN, grease limiting speed 4,700 r/min, oil speed 6,300 r/min, mass about 192 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 32910XU?
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 (32910XU); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 32910XU designation encode the 50 mm bore and what is 2BC?
last two digits 10 are the ISO bore code, ×5 = 50 mm (codes 00–03 use the 10/12/15/17 exception table). The 72 mm OD and 15 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 32910XU list two speeds, 4,700 and 6,300 r/min?
The lower figure, 4,700 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 32910XU at 6,300 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 32910XU mean?
Suffix reading on 32910XU: 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.