32910 bearing: complete specifications & equivalents
The 32910 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 | 35 kN |
| Basic static load rating C0 | 50.5 kN |
| Fatigue load limit Pu | 6.15 kN |
| Limiting speed (mechanical) | 4700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 193 g |
| Manufacturer designation | NTN 32910 |
| 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 | 10 |
| 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 |
|---|---|---|---|
| 32910 | 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 32910 model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, the NTN order number 32910 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. NTN also quotes this bearing with its ISO 355 dimension-series abbreviation which is the maker-neutral cross-reference for the 50×72 mm envelope; 4T is NTN's own tapered-roller brand mark on the parts. At 35 kN C the bearing offers about 0.7 kN of dynamic capacity per millimetre of the 50 mm bore — compare any substitution on this ratio and the 15 mm assembled T, not on bore alone. Selection: C 35 kN against C0 50.5 kN gives a C0/C ratio of 1.44 for the 50 mm bore, and the equivalent combined load must keep below the rating at the target L10 with the pair counted as one unit. Re-adjustment after bedding-in is standard practice: re-check end play once the paired 32910 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
- preload loss from racewear when one bearing of the paired set is replaced without re-adjusting end play
- rib scoring when axial load is carried beyond the cone rib capacity of the adjusted pair
- 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 32910.
- The thin 15 mm section of 32910 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.
- On slash-size and T-code bearings confirm the full code on both cone and cup before fitting: the 50 mm bore alone does not identify the cup, and a mismatched cone/cup set has no catalogue rating.
- The 11.0 mm section leaves little room for an oversized shaft fillet; check the mounting-chamfer table for 32910 or the ring will bottom out on the radius instead of the shoulder face.
- Open 32910 units have no seals: a wheel-hub or gearbox application needs external sealing or the 4,700 r/min grease figure is meaningless once water reaches the cone rib.
- The 35/50.5 kN ratings and 6.15 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 32910; 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 32910?
32910 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 35 kN, C0 50.5 kN, Pu 6.15 kN, grease limiting speed 4,700 r/min, oil speed 6,300 r/min, mass about 193 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 32910?
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 (32910); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 32910 designation encode the 50 mm bore?
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.
Why does 32910 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 32910 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 32910 mean?
It is the basic open 4T execution — steel cage, adjusted mounting, no seal or feature suffix. NTN uses U for the uprated design, UTG for ULTAGE large-bearing specs, X for the ISO boundary section, and C/CA/D/A for contact-angle or internal-design variants; all are separate order numbers.
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.