HM88542-HM88512 bearing: complete specifications & equivalents
The HM88542-HM88512 is a ANSI ABMA 19.2 radial bearing sized 31.75 x 73.812 x 29.37 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 31.75 mm |
| Outer diameter D | 73.812 mm |
| Width B | 29.37 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 80 kN |
| Basic static load rating C0 | 97 kN |
| Limiting speed (mechanical) | 5400 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 638 g |
| Manufacturer designation | NTN 4T-HM88542/HM88512 |
| 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 | 1.25 in |
|---|---|
| Outer diameter D | 2.906 in |
| Width B | 1.156 in |
| ISO bore code | 42 |
| Radial section height (D−d)/2 | 21 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) | 32 of 148 |
| Bore above smallest 4t-inch-series size | 19.05 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| HM88542-HM88510 | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same NTN cone 4T-HM88542 paired with a different cup (HM88510): cone interchangeable, cup differs — OD, assembled width T and ratings follow the cup. Verify the full cone/cup reference before substituting. |
| HM88542-510 | SKF | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue. |
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 HM88542-HM88512 model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, the order number 4T-HM88542/HM88512 denotes the heavy-medium HM family of NTN inch tapered roller bearings — cone HM88542 and cup HM88512 delivered as a matched, separable pair of 31.75 mm bore and 73.812 mm outside diameter. Reading the designation: 4T-HM88542/HM88512 follows the ABMA inch convention — the number before the slash is the cone (inner ring with roller set and cage), the number after the slash is the cup (outer ring), and the heavy-medium HM family lettering ties the pair to its boundary plan. Catalogue mass of the 4T-HM88542/HM88512 cone-plus-cup set is 638 g; shaft and housing shoulders must carry that mass square to the axis during fitting. The printed 80/97 kN ratings belong to the assembled HM88542+HM88512 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-HM88542/HM88512 run near 5,400 r/min lets the rollers skid; lightly spring-preload high-speed pair arrangements.
Typical equipment & failure modes
Common applications
- construction-equipment pivot and wheel positions
- mining and quarry conveyor drive pulleys
- machine-tool headstocks on inch spindles
- pump and blower drive shafts with combined load
Known failure patterns
- rib-face scoring when the thrust share of the combined load exceeds what the cone rib of this size carries
- flaking on one cone only when a bent shaft loads the O/X pair unevenly
- cup creep and housing fretting when the cup seat is cut too loose for the rotating load
- cage damage from a mounting blow transmitted through the roller complement
- water-induced pitting when the open bearing sees washdown without external seals
Selection pitfalls — read before you substitute
- Hub and pinion positions of this 31.75 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-HM88542/HM88512.
- The heavy-medium HM family is proportioned for a high thrust share; swapping to a lighter LM or pure-numeric series at the same 31.75 mm bore cuts axial capacity even when the envelope fits — re-verify the load split before downgrading.
- Replacing one half of an adjusted pair without resetting end play negates the 29.37 mm T logic: re-adjust the set and re-verify the contact pattern rather than reusing the old spacer stack.
- Do not confuse T (29.37 mm, the assembled cone-plus-cup width) with the cone width when drawing spacers; an abutment sized to T leaves the cup unseated.
- Replacing one half of an adjusted pair without resetting end play negates the 29.37 mm T logic: re-adjust the set and re-verify the contact pattern rather than reusing the old spacer stack.
- The 80/97 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-HM88542/HM88512; 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-HM88542/HM88512?
4T-HM88542/HM88512 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 31.75 mm bore (1.25 in), 73.812 mm outside diameter and 29.37 mm assembled width T (2.906 × 1.156 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 80 kN, C0 97 kN, grease limiting speed 5,400 r/min, oil speed 7,100 r/min, mass about 638 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-HM88542/HM88512 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the HM88542 cone or the HM88512 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 80/97 kN ratings change with the cup.
What is the difference between 4T-HM88542/HM88512 and a metric ISO 355 tapered bearing?
4T-HM88542/HM88512 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 31.75×73.812×29.37 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-HM88542/HM88512 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 HM88542/HM88512 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-HM88542/HM88512 list two speeds, 5,400 and 7,100 r/min?
The lower figure, 5,400 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-HM88542/HM88512 at 7,100 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.