HH506349-HH506310 bearing: complete specifications & equivalents
The HH506349-HH506310 is a ANSI ABMA 19.2 radial bearing sized 49.987 x 114.3 x 44.45 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 49.987 mm |
| Outer diameter D | 114.3 mm |
| Width B | 44.45 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 226 kN |
| Basic static load rating C0 | 261 kN |
| Limiting speed (mechanical) | 3500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2310 g |
| Manufacturer designation | NTN 4T-HH506349/HH506310 |
| Standard | ANSI ABMA 19.2 |
| Catalog version | NTN 2203E 2026-09-25 |
| Last verified | 2026-10-01 |
Source: catalog reference (NTN 2203E 2026-09-25) · extracted 2026-10-01
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN 2203E 2026-09-25); 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 & 4t-inch-series range
| Bore d | 1.968 in |
|---|---|
| Outer diameter D | 4.5 in |
| Width B | 1.75 in |
| ISO bore code | 49 |
| Radial section height (D−d)/2 | 32.2 mm |
| Smallest bore in 4t-inch-series | 12.7 mm |
| Largest outer diameter in 4t-inch-series | 260 mm |
| Width range across 4t-inch-series | 10.998–77.788 mm |
| Bore position in 4t-inch-series (smallest first) | 62 of 148 |
| Bore above smallest 4t-inch-series size | 37.287000000000006 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| HH506349 | 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 HH506349-HH506310 model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, the order number 4T-HH506349/HH506310 denotes the extra-heavy HH family of NTN inch tapered roller bearings — cone HH506349 and cup HH506310 delivered as a matched, separable pair of 49.987 mm bore and 114.3 mm outside diameter. Unlike ISO 355 metric numbers, this ABMA code does not encode the bore arithmetically: HH506349 identifies the cone of 49.987 mm (1.968 in) bore by catalogue lookup, and HH506310 fixes the 114.3 mm OD. Contact-angle geometry of the extra-heavy HH family gives 4T-HH506349/HH506310 its radial/axial load split — at 226/261 kN the static rating is about 1.15× C, typical of inch tapered sets proportioned for combined duty. The printed 226/261 kN ratings belong to the assembled HH506349+HH506310 pair; a sibling row using the same cone with a different cup carries its own rating row because the raceway track shifts with the cup. Minimum load matters at speed: an unloaded 4T-HH506349/HH506310 run near 3,500 r/min lets the rollers skid; lightly spring-preload high-speed pair arrangements.
Typical equipment & failure modes
Common applications
- agricultural tractor transmission and PTO shafts
- industrial gearboxes built to inch shafting
- construction-equipment pivot and wheel positions
- mining and quarry conveyor drive pulleys
Known failure patterns
- rib-face scoring when the thrust share of the combined load exceeds what the cone rib of this size carries
- false brinelling on a stationary pair exposed to vibration during transport or standby
- preload loss and noise after one bearing of the adjusted pair is replaced without resetting end play
- cage fatigue when the pair runs continuously near the grease limiting speed without oil cooling
- water-induced pitting when the open bearing sees washdown without external seals
Selection pitfalls — read before you substitute
- Hub and pinion positions of this 49.987 mm class are adjusted in pairs; verify end play against the axle or gearbox drawing and re-torque after bedding-in instead of trusting the first setting on 4T-HH506349/HH506310.
- The extra-heavy HH family is proportioned for a high thrust share; swapping to a lighter LM or pure-numeric series at the same 49.987 mm bore cuts axial capacity even when the envelope fits — re-verify the load split before downgrading.
- Grease packs must leave free volume inside the 44.45 mm-wide set; over-greasing a pair churning near the oil-band speed of 4,700 r/min raises temperature and destroys the setting.
- An unloaded 4T-HH506349/HH506310 near 3,500 r/min lets rollers skid and smear the cone rib; spring-preload lightly loaded high-speed pairs.
- Do not confuse T (44.45 mm, the assembled cone-plus-cup width) with the cone width when drawing spacers; an abutment sized to T leaves the cup unseated.
- The 226/261 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-HH506349/HH506310; internal geometry legitimately differs between inch-series makers, so re-verify ratings, adjustment and the exact cone/cup references before substituting another brand on a rated drive.
Frequently asked questions
What are the dimensions and catalogue ratings of NTN 4T-HH506349/HH506310?
4T-HH506349/HH506310 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 49.987 mm bore (1.968 in), 114.3 mm outside diameter and 44.45 mm assembled width T (4.5 × 1.75 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 226 kN, C0 261 kN, grease limiting speed 3,500 r/min, oil speed 4,700 r/min, mass about 2310 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-HH506349/HH506310 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the HH506349 cone or the HH506310 cup can be replaced by an identical reference from NTN or another ABMA-dimensioned maker. Pairing the cone with a different cup reference is a different catalogue row: OD, assembled T and the 226/261 kN ratings change with the cup.
What is the difference between 4T-HH506349/HH506310 and a metric ISO 355 tapered bearing?
4T-HH506349/HH506310 follows the ABMA inch boundary plan with cone/cup references; ISO 355 bearings use metric dimension-series numbers (302, 322, …). Even where a metric size looks close to 49.987×114.3×44.45 mm, the envelopes and contact angles differ — the two systems are not drop-in interchangeable; check every boundary value before substituting.
What does the 4T prefix on 4T-HH506349/HH506310 mean?
4T is NTN's tapered roller bearing quality mark, stamped on cone and cup in the factory. It identifies NTN's 4T programme and is not a dimension or variant code, so interchange lists quote the bare HH506349/HH506310 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-HH506349/HH506310 list two speeds, 3,500 and 4,700 r/min?
The lower figure, 3,500 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 4T-HH506349/HH506310 at 4,700 r/min because oil removes rib-contact heat better. Real limits still depend on pair adjustment, oil flow and cooling.
Reviewed & verified by the MPN Base engineering desk against source catalog NTN 2203E 2026-09-25 on 2026-10-01. Read our editorial & correction policy.