32256UTG bearing: complete specifications & equivalents
The 32256UTG is a ISO 355 radial bearing sized 280 x 500 x 137 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 280 mm |
| Outer diameter D | 500 mm |
| Width B | 137 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 2530 kN |
| Basic static load rating C0 | 3500 kN |
| Fatigue load limit Pu | 283 kN |
| Limiting speed (mechanical) | 630 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 110000 g |
| Manufacturer designation | NTN 32256UTG |
| 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 & 32200-series range
| Bore d | 11.024 in |
|---|---|
| Outer diameter D | 19.685 in |
| Width B | 5.394 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 110 mm |
| Smallest bore in 32200-series | 17 mm |
| Largest outer diameter in 32200-series | 580 mm |
| Width range across 32200-series | 17.25–159 mm |
| Bore position in 32200-series (smallest first) | 34 of 36 |
| Bore above smallest 32200-series size | 263 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 32256UTG | 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 32256UTG model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, the NTN order number 32256UTG denotes the heavy-section 32200 family of metric tapered roller bearings, 280 mm bore, 500 mm outside diameter and 137 mm assembled width T (11.024 × 19.685 × 5.394 in) to the ISO 355 boundary plan. Reading the designation: the leading five digits follow the ISO 355 metric plan (dimension family plus two-digit bore code), and 32256UTG resolves to 280 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. The rollers run with their large ends against the cone's integral guide rib; the rib/end-flange contact carries the thrust component and is the reason lubricant must reach the rib face of 32256UTG, not only the raceway. The 110.0 mm section height over the 280 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. Open 4T bearings need application seals; without them the grease at the cone rib of 32256UTG washes out and the rib/roller-end contact smears on the first wet or dusty shift.
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
- pressed-steel cage pocket wear from roller skid at light radial load and high speed
- rolling-contact fatigue after the catalogue L10 life at the actual combined load
Selection pitfalls — read before you substitute
- At 280 mm bore the 32256UTG 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 2530 kN C level.
- The heavy-section 32200 family at 280 mm bore (500×137 mm assembled) carries more capacity than the lighter 320/329 sections but generates more preload heat; confirm oil availability before running near the 900 r/min oil ceiling.
- Grease packs must leave free volume in the 137 mm-wide set; over-greasing a paired bearing churning at the 900 r/min oil-band speed raises temperature and destroys the preload setting.
- Minimum load matters at high speed: an unloaded 32256UTG at a large fraction of 630 r/min lets rollers skid and smear the cone rib; spring-preload lightly loaded pair arrangements.
- Back-to-back and face-to-face arrangements react differently to shaft bending: pick the pair orientation for the moment load before locking the 280 mm shoulder geometry, because retrofitting flips the cups.
- The 2530/3500 kN ratings and 283 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 32256UTG; 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 32256UTG?
32256UTG is a metric 4T tapered roller bearing to ISO 355: 280 mm bore, 500 mm outside diameter and 137 mm assembled width T (11.024 × 19.685 × 5.394 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 2530 kN, C0 3500 kN, Pu 283 kN, grease limiting speed 630 r/min, oil speed 900 r/min, mass about 110000 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 32256UTG?
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 (32256UTG); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 32256UTG designation encode the 280 mm bore?
last two digits 56 are the ISO bore code, ×5 = 280 mm (codes 00–03 use the 10/12/15/17 exception table). The 500 mm OD and 137 mm assembled T follow the ISO 355 dimension-series plan.
Why does 32256UTG list two speeds, 630 and 900 r/min?
The lower figure, 630 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 32256UTG at 900 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 32256UTG mean?
Suffix reading on 32256UTG: the UTG suffix marks the ULTAGE specification for large NTN tapered rollers — upgraded material and internal design for longer life inside the unchanged ISO 355 envelope; 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.