32324U bearing: complete specifications & equivalents
The 32324U is a ISO 355 radial bearing sized 120 x 260 x 90.5 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 120 mm |
| Outer diameter D | 260 mm |
| Width B | 90.5 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 905 kN |
| Basic static load rating C0 | 1130 kN |
| Fatigue load limit Pu | 114 kN |
| Limiting speed (mechanical) | 1500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 22100 g |
| Manufacturer designation | NTN 32324U |
| 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 & 32300-series range
| Bore d | 4.724 in |
|---|---|
| Outer diameter D | 10.236 in |
| Width B | 3.563 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 70 mm |
| Smallest bore in 32300-series | 20 mm |
| Largest outer diameter in 32300-series | 460 mm |
| Width range across 32300-series | 22.25–154 mm |
| Bore position in 32300-series (smallest first) | 21 of 30 |
| Bore above smallest 32300-series size | 100 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 32324U | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier. |
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 32324U model number is decoded
The NTN 2203E table prints 32324U in the extra-heavy 32300 family: 120 mm bore, 260 mm cup OD, 90.5 mm T, with a grease limiting speed of 1,500 r/min and an oil-lubricated ceiling of 2,000 r/min. Reading the designation: the leading five digits follow the ISO 355 metric plan (dimension family plus two-digit bore code), and 32324U resolves to 120 mm bore; the NTN factory mark 4T is stamped on cone and cup but is a brand mark, not a size code, so the catalogue sku is printed without it. Suffix reading on 32324U: 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. The fatigue load limit Pu printed for 32324U is 114 kN; in the adjusted-life equation that is the equivalent-load floor below which high reliability is expected even under contamination. When pairing 32324U with a second tapered bearing, keep the matched arrangement clean: a single stray grit particle between cup and housing changes preload faster than the adjustment range can correct.
Typical equipment & failure modes
Common applications
- heavy haul railway traction gearboxes
- large marine propulsion reduction gears
- cement-plant kiln and mill drive trains
- rolling-mill roll-neck and gearbox positions
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
- cage fatigue when the pair is run continuously near the grease limiting speed without oil cooling
- water-induced pitting when the open bearing is exposed to washdown without external seals
Selection pitfalls — read before you substitute
- At 120 mm bore the 32324U set is adjusted with hydraulic nuts on large mill and wind positions; follow the drive-up angle/end-play procedure, because manual torque methods cannot control preload at the 905 kN C level.
- The extra-heavy 32300 family at 120 mm bore (260×90.5 mm assembled) carries more capacity than the lighter 320/329 sections but generates more preload heat; confirm oil availability before running near the 2,000 r/min oil ceiling.
- Minimum load matters at high speed: an unloaded 32324U at a large fraction of 1,500 r/min lets rollers skid and smear the cone rib; spring-preload lightly loaded pair arrangements.
- Grease packs must leave free volume in the 90.5 mm-wide set; over-greasing a paired bearing churning at the 2,000 r/min oil-band speed raises temperature and destroys the preload setting.
- ISO 355 makes the 120×260 mm envelope interchangeable but not the ratings: NTN prints 905/1130 kN for this execution, and a cheaper same-number part can differ in roller complement and steel.
- The 905/1130 kN ratings and 114 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 32324U (ISO 355 2GD); 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 32324U?
32324U is a metric 4T tapered roller bearing to ISO 355: 120 mm bore, 260 mm outside diameter and 90.5 mm assembled width T (4.724 × 10.236 × 3.563 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 905 kN, C0 1130 kN, Pu 114 kN, grease limiting speed 1,500 r/min, oil speed 2,000 r/min, mass about 22100 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 32324U?
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 (32324U); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 32324U designation encode the 120 mm bore and what is 2GD?
last two digits 24 are the ISO bore code, ×5 = 120 mm (codes 00–03 use the 10/12/15/17 exception table). The 260 mm OD and 90.5 mm assembled T follow the ISO 355 dimension-series plan. 2GD 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 32324U list two speeds, 1,500 and 2,000 r/min?
The lower figure, 1,500 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 32324U at 2,000 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 32324U mean?
Suffix reading on 32324U: 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.